Needle-nose pliers for zip tie trimming.
  • Needle-nose pliers for zip tie trimming.

  • 2.5mm Allen key for M3 screws

  • 2mm Allen key for nut alignment

  • 1.5mm Allen key for tightening the pulley

Can’t figure out how to let author know it took me 4 hours 45 minutes to complete. I’m probably a bit on the slow side and made a few slight errors along the way, so consider this a upper bound? Jakub Dolezal feel free to delete this once it gets read

timcdoc - Reply

I'm pretty quick and it took me 1 hour 15 minutes. Definately clean all holes on the printed parts before assembling using the smallest Allen key to speed things up. There were quite a lot of strings on the overhangs that break off easily with a tool but not with a nut. Also I found the hole for the bottom of the heatsink was not quite round enough, a touch of sandpaper brought that in nicely.

Chris Vahi - Reply

For the following steps, please prepare:
  • For the following steps, please prepare:

  • Extruder-idler (1x)

  • Bondtech pulley WITHOUT the lock screw (1x)

  • Pulley bearing (2x)

  • M3nS nut (2x)

  • Pulley shaft (1x)

  • Note there are two types of the Bondtech pulley in the package (one with and without lock screw). Make sure you are using the correct one.

For those who have a shocking moment here as it looks like one pulley bearing is missing… have a look inside the bondtech pulleys ;)

Stefan Lutz - Reply

^ What he said :) ^

Danzanzio@yahoo.com -

Yuup!!! Same thing in my bag.

Douglas Shelfoon - Reply

When sorting through the pieces it appears I have an extra grub screw … the bondtech has one in place, and another is loose. Is it just an extra?

Rich - Reply

Same with the grub screw, extra?

Mark Moore - Reply

My packet label only references 1 Bondtech and doesn’t show the pulley bearings at all. It’s v1.9. All the parts are there though, including the extra grub screw.

Shaun Collins - Reply

Ditto. Mine too.

Jeremy Mayes -

English hint: it is called a ‘hobbed gear’. Pulleys are for belts and gears have teeth to mesh with other gears. The ‘hobbed’ portion is where the small teeth have been added to engage the filament.

Timothy W. Skloss, Ph.D. - Reply

Hi Timothy, thanks for the explanation. I intended to rename them to the drivegears in the next update to comply with the manufacturer’s description.

Jakub Dolezal -

Press the nuts to the slots on both sides of the idler. Insert both bearings in the pulley. Be aware that bearings can slip out during assembly.
  • Press the nuts to the slots on both sides of the idler.

  • Insert both bearings in the pulley. Be aware that bearings can slip out during assembly.

  • Layers might be visible in this printed part due to the geometry. The functionality and strength remain unaffected.

There is no printed part here. Perhaps the comment should be on the next picture

Steve Worcester - Reply

Hi Steve, the black idler (first picture) is 3D printed.

Jakub Dolezal -

I am unable to get the right nut in far enough to put a screw through. Probing with an Allen key it feels like there is a blockage in one corner. Is there a good process to clean this out?

Frank Riddle - Reply

Hi Frank, to clean the slot I use the smallest Allen Key, it works pretty well.

Jakub Dolezal -

The slots for these two captive nuts isn’t especially tight. They fall out whenever you move/touch the part. I suggest that either the slots should be tighter, or the step with the nuts should be moved to step 15.

Duane Pinkerton - Reply

Completely agre with ++Duane Pinkerton++ same happened to me should be step 15

PaulHarris - Reply

My M3nS nuts kept falling out.

Suggest you use x2 M3 x 10 screws and engage into the nuts, with no pressure. This will hold the M3nS nuts from falling out. These 2 screws can be removed later, at step 15.

Mike Norman - Reply

Ensure both bearings are inside the pulley! Insert the pulley in idler as shown in the picture.
  • Ensure both bearings are inside the pulley!

  • Insert the pulley in idler as shown in the picture.

  • Slide the shaft through the idler and pulley. Use reasonable force or you will BREAK the printed part.

  • Place your finger on the bearing and ensure it can rotate freely.

Any suggestions on how to get the shaft in? It’s impossible with my parts. Might have to try and ream out the hole.

Alex Tramiel - Reply

Since the shaft is 3mm - I´d suggest using a 3mm drill bit and widen up the first hole - by hand preferably.

Richard Rohan -

put the champfer-side into the hole (direction of the orange arrow is good) then take a wood or plastic on your workbench.

hold the printed part vertically and slightly push downwards.

Heiko Schultz -

Hi Alex, did you manage to press the shaft in?

Jakub Dolezal -

For me, the holes in the printed part were too small. I enlarged it with a small round file.

Michal - Reply

The hole can not be too big so that the shaft does not fall out.

Michal - Reply

No way to get this in by hand, but a pair of channel locks worked as sort of arbor press, and popped right in.

Scott - Reply

Channel locks worked like a charm and were smooth so I didn’t feel like I was going to break anything.

Cliff Miller -

This worked for me also. It doesn’t require much compression with the channel locks so you really don’t feel like you are going to break anything. As soon as I started to use them, the shaft started going in very easily.

John Haro -

I drilled mine out and epoxied in the shaft. It was so tight I felt sure I would break the part before getting it in. I would rather have pressed it in, but it was just too tight!

Steven Underwood - Reply

Guys, feedback noted and production team alerted. Thank you :)

Jakub Dolezal - Reply

also, the shaft is about 3.6mm too short. I inserted it (sadly I read about the necessary drilling too late ;(( ) an now it’s flush on one side and still 3.6mm to go on the other side.

Guntor H - Reply

Hi Guntor, can you please share a picture? (http://manual.prusa3d.com/Answers) Thanks

Jakub Dolezal -

I hand-drilled the entry hole to widen it slightly but left the other hole as-is. It seems to have worked well for now.

Brandon Oprendek - Reply

I did the same as Brandon - it worked ok but the system needs improving here

Chris Tipney - Reply

Hi Chris, it is already fixed, but due to the amount of already shipped printers it will take some time. Sorry about that.

Jakub Dolezal -

Shaft is indeed a bit short but I used one of the allen wrenches to just push it in a little further so it has a bit of ‘flesh’ on both sides. Guess shaft could do with an additional 2mm in length (at least).

Jeroen - Reply

Same problems over here: Holes to tight and shaft to short

Another thing:

On the bag is only one part mentioned (1x Bontech). So at first I did not realised that there are two different parts

Gerhard Kunz - Reply

Hi Gerhard, it is written in the first step to use Bondtech pulley without tightening screw.

Jakub Dolezal -

Same as @kunzgbr - I had two similar looking parts in E-Axis bag which was labeled 1xBondtech. I notice now one of them has an allen lock screw, so I used the one without the lock screw for this step. Not sure if the other is needed or not yet.

Graham McIntyre - Reply

Hi Graham, yes for this step use the without the lock screw. It is written in the first step of this chapter.

Jakub Dolezal -

Too short by about the thickness of one of the hangers

Steve Worcester - Reply

Rubber mallet here, went just fine without drilling, but shaft could be 2 or 3 mm longer. I managed to make it equally spaced

Giacomo - Reply

Note: before leaving this step I would recommend you tap on the extruder and verify that the pin does not shift out of place. if the pin walks out, then you will not be able to generate good prints. It may be possible to add just a touch of super glue to the end cap to prevent the pin from walking out. Another option is to use a hot glue gun to secure the part in place. A longer pin would make this part more reliable.

Bradley Moreavek - Reply

Slight touch up with a small, round file…tight friction fit…equally spaced and then a drop of super-glue seems to have worked for me.

Matt Plummer - Reply

I used a big clamp very carefully to get it in, then I took the included screwdriver and drove the pin farther in by smacking the screwdriver with a metal wrench. Worked ok.

Mr Cookie - Reply

I just used the included pliers to press it in. Make sure the shaft is as straight/perpendicular as possible and use the pliers to press it in. One tip of the pliers is on the end of the shaft and the other is on the back side of the near tab (ie. the first one the shaft goes through) Once the shaft is flush with the inside wall or sticking out just a half mm or so you can put the gear in and press the rest of the way. This way the pliers support the printed part while pushing the shaft in. This minimizes the chance you will break the printed part. If you drill it out or file it, it will be easier to push in by hand but also easier for the shaft to work loose.

Also the shaft seems too short. Should be a mm or two longer as others have stated.

Bryan Jackson - Reply

It’s way easier to insert once you realize the shaft has one chamfered side you need to insert first. Then press the entire part down on the shaft, with the shaft resting on a wood surface. I pushed it in a little further using the philips head, that solved the length issue as well. Wouldn’t have known this without @predatorjr mentioning the chamfered edge on the shaft.

Bas - Reply

Good information Bas, Thank you. No need to drill. Just press the entire part on a wood surface.

Jacques Bourdouxhe -

Great Information Bas. Inserting the chamfered side first and a little tap-tap with pliers, and it when right in.

Paul Bowers -

As others have said, the shaft is not long enough

Richard - Reply

Yes, knowing that one side of the shaft has slightly rounded edges (chamfered) compared to the other more square-cut end definitely made a difference. No issue pressing it in by hand. That said, as others have noted, 1-2mm of extra length would help the situation. Took a little careful back and forth to get the shaft centered between the two mounts.

Kalani - Reply

I could not get the shaft in. Slightly pressed it like others have set and broke one side. I’ll try and get it in and super glue it. Then try and print that part again for a replacement once the printer is working. This has been the hard part of the build for me.

Michael Aldrich - Reply

The shaft on my pre-assembled mk3 is indeed too short. After around 200 hours of use , I noticed my filament slipping no matter how much I tightened the idler. The shaft had slipped to the side allowing the idler to lose contact with the filament.

Robert Klein - Reply

This is still way too hard to get it and its from 3/14/18

Alex Paradis - Reply

Just press it against a table before putting the idler in. Keep your thumb over the hole. Once you feel the shaft start to come through, then put the idler in and press the rest of the way.

phr0ze -

Before you put the idler in, use your thumb to press the shaft into the first part. Just press the shaft against the table and you will feel it press in pretty easy. Now add the idler with the bearings and press the shaft the rest of the way on the table. However the shaft will still not be in enough. For the next step take a M3x10, add a nut to it and screw it in to expose 1-2mm of screw. This nut is a stopper. Balance the pin on the top of the screw and press it in so the pin goes far enough but not too far. If you have problems balancing the M3x10 you can use the hole in the center of the X Axis cover to hold the screw upright.

phr0ze - Reply

the shaft really should be a couple mm longer. It’s hard to center in the shaft and make sure it’s not going to wobble. I didn’t have any issues inserting, a little force got it done.

Jesse Brockmann - Reply

Agree with everyone else on this one. Shaft is too short by a couple mm and the hole is too tight to get the shaft into without a bit of modification. Highly recommend corrections to the design.

Dave S - Reply

The holes for the shaft were extremely tight, so I did not dare apply a strong force that would tend to break off one of the holders. I live in the US, and I don’t have a 3mm drill. So I drilled out one side only to 1/8”, which is 3.175mm, but I left the other side unchanged. This allowed me to easily insert the shaft through the modified holder, and through the idler pulley bearings. Then I could rest the other side on the edge of my work table and push the shaft into that side without risk of breaking the side off. As others have noted, the shaft is too short, so I used an M3 bolt as a “drift pin” to push the shaft further into the far side support, ending up with the shaft equally “indented” from each end.

Jay Sinnett - Reply

This was very difficult and time-consuming.

Taylor Mills - Reply

+1 for channel locks. Slid right in. Followed up with some light tapping with a screw driver to drive the shaft a little deeper.

Vince - Reply

Please don’t drill the hole out any bigger! I just pushed it in a little bit, just so it wouldn’t move, by pressing it against the metal part of the pliers. Then I used a small hammer to push it in as far as I could and then used the flat head screw driver provided, placed it on the pin, and hammered it in so that it was centered. Hope this helps :)

Danzanzio@yahoo.com - Reply

I had the same issue with the length of the shaft. I replaced it with a new 3mm shaft 2.35mm long. All the alternatives seem less than satisfactory since one relies on the short shaft not moving over time. There is at least one YouTuber showing how this happened to him and it took him forever to find the problem.

john.geaney@bluewin.ch - Reply

Those of us that have done the Prusa upgrades in the past have a 3mm drill bit with a hand knob to clean the hole out. This works great. Take your time. Never drill the holes oversized or the shaft will move and one side or the other will get cocked and you will have a tough time troubleshooting the problem some time in the future! Someone posted a youtube video with that exact problem.

Keep in mind that you want a nice friction fit. You can use a vice to press the shaft assembly together.

The shaft does not have to be full length…Press the shaft in from the narrower (furthest out from center) support side and press it in just a bit past flush.

Kelly Anderson - Reply

This was a very tight fit. I used my work space top to press against which got the shaft flush with the top face. It did take a bit of force pushing down on the assembly. Like everyone else, I also noted that the shaft when flush with the top face does not seat into the lower support frame. I used a pin punch and hammer to tap it more, so that both supports had some of the shaft. I can upload the couple of photos I took if that would be helpful.

David Jerrell - Reply

The pulley shaft does appear to be a few millimeters too short. when the trailing end of it was fully inserted, flush with the plastic surface of the idler, I was concerned that the leading end might not be extending far enough into the hole at the opposite end of the pulley.

My solution was to brace the idler vertically against my work table and use a light hammer and nail set. A few light taps drove the pulley shaft a few more millimeters, so now the shaft faces are recessed a millimeter or two from the ends of the holes on both sides. Nothing cracked, and the pulley spins freely.

Charles - Reply

I agree, the shaft is a really tight fit and was hard to get it in place, and as has been said, a little short to know that it is in place correctly, I used the pliers to grab the end and gently wiggled it into the hole, then finished off with a gentle tap to ensure the pin was located in the opposite hole, but was hard to determine if it was far enough in to be mechanically sound for printing, with a longer shaft the ends could line up at both ends of the printed part.

Martin Wright - Reply

The hole for the shaft is way to small. I broke this part. I have to print it. So many people with this issue, and the design still not changed.

Claude Serquet - Reply

Hi Claude, the hole must be narrow in order to keep the shaft in place. We've made some adjustments and we will do more.

Jakub Dolezal -

I used an included screw to “file” the hole slighly bigger. Then I placed the Bondtech between the two plastic petrusions and pushed the pin in by placing the part against the table.

When the axle did not stick out from the printed part any more, I pushed in the rest with an Allan key (it will slip back and forth a few times, try gentle hits to center the axle.)

Tor Andre - Reply

Applied PTFE grease to bearings and shaft before installing, and gear area afterwards (I would have used white Lithium grease, but discovered most brands don’t contain any Lithium despite the label, and use Zinc Oxide instead).

Instructions should state to insert the shaft chamfer-end first! Then, press it against flat face of pliers (to ensure a hard surface, and avoid tabletop damage). Stop applying force when shaft moves, and repeat until shaft is fully seated.

Shaft went in after about 5 pressings. With an extra final pressing to make sure the shaft end was perfectly flush with the surface.

The shaft is slightly too short. It doesn’t fully penetrate the thicker support. This could be by design(?) to ensure that the shaft never protrudes from either side.

Andrew E. Mileski - Reply

Hi Andrew, we are working on a new design for this part, as soon as it is ready the instructions will follow. Thanks for the feedback and the tips ;)

Jakub Dolezal -

Channel lock pliers seem to work the best! No hole drilling, filing, etc.

Christian Horner - Reply

Maybe improvements were made since the previous reviews, but I’m astonished how this step is causing difficulty for so many people. I used a fully-fledged hammer like a neanderthal, as in the same kind that houses are built with. Just place the part sideways on the edge of a hard worktable; with everything hanging over the edge except the “shaft holders” which makes them flush against the surface. Gorilla-grip the entire part to secure it if you want to be extra safe. But a few taps was all it took, and it wasn’t going in “by hand” prior to trying this either. Plus breaking it was never even the slightest worry. The shaft is still short, but once again just use an Allen wrench as like a hole punch and tap it in until centered if it bothers you that much.

David - Reply

Widened the hole a tiny, tiny bit with a round file to enable using a reasonable amount of force and lessen the chance of breaking the printed part. Also used the very nice tip from @phr0ze to use a screw and nut to help center the pin!

Christian Kullander - Reply

I used a small C-clamp to push the shaft in easily.

Doug Smith - Reply

I assembled this without drilling or anything. Just make sure you can press down the assembly - with the shaft straight - on a flat surface. To get it all the way in my little plastic bag included a small screw I cannot identify. A bit like the fastening screw on the bondotech pully. I laid that on a flat surface to push the assembly on it and push the shaft further in. Wiggle it out carefully afterwards with sa small screw driver.

Alain Geenrits - Reply

BE CAREFUL with the filament sensor, do not touch the black PCB nor the chips on it.
  • BE CAREFUL with the filament sensor, do not touch the black PCB nor the chips on it.

  • For the following steps, please prepare:

  • Extruder-body (1x)

  • Filament sensor (1x)

  • The filament sensor is in the box labeled "2.3.4.5 SUP".

  • M3x10 screw (1x)

  • M3n nut (2x)

The step 5 / PACKaging is not correctly labled — I have 2 large and a small package. One contains screws, the other the plastic parts, the small package contains the parts from step 2. I’m missing the filament sensor from this step.

PEB - Reply

corection - found it ….it is in the carton package. That should be mentioned in the description

PEB - Reply

Thanks for the suggestion, I'm working on something already ;)

Jakub Dolezal -

Definitely agree that you should mention that the filament sensor is found in the “2.3.4.5 SUP” box, and also mention that it’s in a static-protection envelope.

Bill Magley - Reply

Hi Bill, description was updated. Thanks for the feedback ;)

Jakub Dolezal -

It says not to touch the black PCB or the chips on it. What should we touch? Is it safe to hold by the edges or should we grasp the metal prongs?

Jason Coleman - Reply

Hi Jason, please hold the sensor on the edges.

Jakub Dolezal -

Its static sensitive ,only a problem on really dry days. you could ground your self ?

Phillip Kearney - Reply

Hi Philip, I suggest ground yourself first (touch some metal) and then hold the sensor only on the edges not on the sides with the chips.

Jakub Dolezal -

Current body version is B6 if you want to mention it’s different than the pictures.

Evan - Reply

Hi Evan,

No matter the version of the printed part the assembly process should be the same. In case our new version of the printed part changes significantly, the manual gets updated accordingly. Thanks for the suggestion ;)

Jakub Dolezal -

The warning about not touching the sensor should appear BEFORE you are asked to prepare it. Not everybody read the whole instruction before doing the step-by-step operations.

Anders Roer Jensen - Reply

Hi Anders, order changed, however I strongly advise to read all the instructions for any step before doing it.

Jakub Dolezal -

I don’t know if anything can be done but from this point on, once the PCB is in place then you have the 4 connector prongs sticking out of the head. Whilst constructing the rest of the head you need to be careful not to put the piece down with these on the bottom and you also need to be aware of these whilst handing the head whilst building the other components. Maybe some sort of protective cover could be introduced which will reduce the fragility of these prongs. I did end up slightly bending one of them but it was only slight and didn’t cause any problem.

It might be better to move the step so that the board is fitted after the hot end is in place in order to minimise the potential problem.

Stephen Boyd - Reply

Before we continue with the assembly, we need to insert nuts in the Extruder-body. Take the extra time and effort to place them in properly. You won't be able to reach them later. Rotate the front part towards you and insert the M3 nut in the slot, all the way in.
  • Before we continue with the assembly, we need to insert nuts in the Extruder-body. Take the extra time and effort to place them in properly. You won't be able to reach them later.

  • Rotate the front part towards you and insert the M3 nut in the slot, all the way in.

  • Rotate the rear part towards you and insert the M3 nut in the slot, all the way in.

  • If you can't push the nuts in, use a longer screw from the other side and tighten it until you "pull" the nut in.

hint how to easily place nuts , just use one of M3 nuts you have from E package, screw nut with 1 turn on M3, place nut in the hole, check it is perpendicular, turn screw 1 turn back so nut is released, piece of cake, in the nut has to be deeper use longer M3 screw, you can use your thumb to press it in space

ufon - Reply

On my Part B3, the hole for the 2nd nut (the blue one) was oversized and the nut spun freely inside the part. I was able to use the flathead screwdriver to hold the nut in place while screwing it doen from the other side. When it was tight to the bottom of the hole the nut gripped the part.

Chris Pardy - Reply

I think this step can be moved to the end. I disagree with the note that you can’t add the nuts until the end because you can’t reach them later. The nuts kept falling out of the printed parts, so I left it until after step 18 IIRC with no problems.

Jon Le - Reply

Hi Jon, thanks for the suggestion. The reason for this order of steps is because of the filament sensor, which can be damaged while inserting the front (yellow) nut and forgetting there are pins on the other side. I’ve tested the assembly several times and these nuts were OK, I will recheck it.

Jakub Dolezal -

Step 6 M3 nut in front can’t be pulled down by M10 bolt, it isn’t obvious that this is ok? We don’t want anyone crushing the plastic trying to make this happen.

timcdoc - Reply

I noticed that if you push the nuts down all the way it is a snug fit and they don’t fall out. I tapped mine down with the phillips screwriver.

Larry Kmiecik - Reply

Carefully insert the filament sensor in the slot, do not use force or you might damage the PCB! Carefully insert the filament sensor in the slot, do not use force or you might damage the PCB!
  • Carefully insert the filament sensor in the slot, do not use force or you might damage the PCB!

Is the sensor PCB supposed to be loose in the slot?

Aubry Thonon - Reply

For now yes, you will tighten it in the next step.

Jakub Dolezal -

Turn the extruder-body like in the picture. The pins of the filament sensor must be facing up. Locate the opening for the M3 screw.
  • Turn the extruder-body like in the picture. The pins of the filament sensor must be facing up.

  • Locate the opening for the M3 screw.

  • Take the M3x10 screw and tighten the sensor in place. No nut is needed, the screw will self-tap into the plastic.

  • The sensor must be tightened completely to prevent its movement BUT BE CAREFUL during tightening to avoid damage to the sensor.

  • Layers might be visible in this printed part due to the geometry. The functionality and strength remain unaffected.

Does the head of the screw touch the sensor? I seem to be screwing into plastic and I’m not sure how far to go with it.

Mark Abrams - Reply

Hi Mark, the head of the screw must touch the PCB of the sensor. Be careful during tightening ;)

Jakub Dolezal -

There is an issue. No filet in the pcb and not enough space between the pcb and the plastic part to put a nut. So you must carefully make a hole with a drill (in screw direction) to have enough space to put a nut. But Prusa has to modify the manual and the parts.

Xavier - Reply

There is no nut involved when fixing the sensor, the M3x10 bolt is self-tapping into the plastic.

Robert Hunt -

Hi Xavier, as Robert said, there is no need for a nut, the screw will self-tap into the printed part.

Jakub Dolezal -

I was able to secure it fully by continuing to screw into the plastic until the screw head presses snuggly against the sensor. I think it would be useful to other makers to show the result from the left side (based on the current photos as “front facing”) to show what to look for.

Mark Abrams - Reply

Hi Mark, thanks for the feedback. I will consider extra picture to show properly tightened sensor.

Jakub Dolezal -

Agreed, a left side picture would make it much clearer. I was not comfortable tightening it down that far until I read the comments.

moacg -

Hi. I noticed the senzor itself (sensory part) is looking dirty. Probably I should no attemp to clean… Or?

Juraj Mr. - Reply

Hi Juraj, the sensor shouldn't be dirty otherwise it won't recognise the filament correctly. Best is to use compressed air, in other words avoid direct contact with the sensor.

Jakub Dolezal -

I was also a bit confused that there was no nut trap/nut for this assembly. It might be wise to include a comment in the instructions when you have screws going directly into plastic. There are a few other screws that are used this way. It would be good to have a heads up. Also since M3 screws in plastic can easily strip, a warning not to over-tighten would be good.

Bryan Jackson - Reply

I agree. I was trying to figure out where I missed a step about installing a nut, but then I saw the comments. A note that it screws into the plastic would be nice.

Guido Kimble -

Wich type of nut we have to add and were please

Sébastien ROUSSELLE - Reply

Hi Sébastien, no nut need for this step.

Jakub Dolezal -

I also agree - it would be good to mention that the screw is going into plastic. After the screw failed to bite a few times, I removed the filament sensor and got the screw started with a few threads, then I removed the screw and reinstalled the filament sensor. The screw was much easier to start after that (still being careful since it’s going into plastic). I’m not extremely confident that I have the screw tightened enough, yet not too much - the sensor seems to be fixed in place, so I’m stopping there.

Bill Magley - Reply

It’s probably a better idea to tighten the screw into the printed part “before” fitting the sensor to cut the thread first, then remove screw, fit sensor and then tighten as described..

Martin Wright - Reply

My sensor looks dirty as well. Almost like some grease on it or something. Do I need to be concerned?

Steven Maguire - Reply

Hi Steven, finish the assembly and you will see during the prints, if the sensors triggers false alarms, then please contact our support. You will change it in the matter of minutes.

Jakub Dolezal -

I’d add a “wiggle” test to the instructions, and note there will be no other opportunity to tighten the screw again.

You don’t want to discover the filament sensor is still loose in step 28.

Don’t ask me how I know.

:cries:

Andrew E. Mileski - Reply

Hi Andrew, I hope the instructions are pretty clear on this matter, you have to completely prevent the movement of the sensor.

Jakub Dolezal -

I also had an issue with this, and I was brought back to this from Step 28. It seems like the screw is going in a very long way, but the head of the screw is what holds the sensor so it won’t move. I had to pull the idler off (and those small plastic washers), which was easy to do, but it gives some concern when putting it back together since the washers are small, thin, and seemingly difficult to put back in place. Turned out easier than it appeared. I’d recommend some added info describing how the head of the bolt is what holds the sensor in place. After the head of the bolt contacts the sensor, it only takes a little extra turning to lock it solidly in place. A picture showing the head contacting the sensor would be self-explanatory.

George Miller - Reply

For the following steps, please prepare:
  • For the following steps, please prepare:

  • M3x30 screw (1x)

  • M3 translucent washer (2x)

  • Translucent washers are placed on the idler for better visibility. No need to place them as in the picture ;)

Picture in Step 9 is a bit confusing, this part is not in the MK3 kit in this form ;-)

Jeroen - Reply

Hi Jeroen, since the washers are transparent, some darker background was needed ;) and you will use the idler in the next step anyway.

Jakub Dolezal -

Being a bit pedantic here, but the washers are translucent, not transparent :P

H4irBear - Reply

Hi, yes you are right, thanks for the correction ;)

Jakub Dolezal -

I find the text for this illustration is written in poor English and therefor hard to understand at first.

I suspect “due to better visibility for the viewer “ should be something like “so the viewer can see them better“

Bernard Higonnet - Reply

Thank you, description updated.

Jakub Dolezal -

Turn the Extruder-body like in the picture. The pins must be facing to the right. Insert M3x30 screw in the hole.
  • Turn the Extruder-body like in the picture. The pins must be facing to the right.

  • Insert M3x30 screw in the hole.

  • Place a washer from the other side.

  • Assemble the idler on the M3x30 screw.

  • Finish the assembly with the second washer.

only one washer in picture use. please arrow secound washer on picture

theerachai - Reply

Look at both photos for Step 10. It’s between the extruder body and the idler.

J Allen -

Hi, first washer is marked with green arrow, second washer with orange circle. Please, check the pictures again ;)

Jakub Dolezal -

How tight should I tighten the screw?

Raynald Bijosono - Reply

Hi Raynald, you can’t tighten the screw right now as there is no counterpart. However, this screw is holding the idler, so later on, don’t tighten it too much. The idler must be able to move/rotate.

Jakub Dolezal -

I used a nut temporally do hold the second washer on place. This after I dropped it two or three times to the floor and had to search it ;-)

Wolfgang Peters - Reply

second this ^. I did the same thing as a safeguard.

tim -

Clever, thanks :D

Tor Andre -

+1 - I did the same thing.

moacg - Reply

Thanks guys - So did I

Michael Tillbrook - Reply

+1 works like a charm.

pariah_l@yahoo.com - Reply

M3x30 doesn’t seem long enough to go through the extruder body the other piece. Additionally the hole that the M3x30 goes into is angled down and doesn’t look like the picture. Yes this just on my piece or are others seeing that was well?

Arezendes - Reply

As in the photo they use a m3x40 but saying it is a m3x30. The 30 is too short and the 40 is exact the same as the picture

Robin -

EDIT: keep in mind there is a m3x25 and m3x30. I took the 25 instead of the 30.30 fits right

Robin -

For the following step, please prepare:
  • For the following step, please prepare:

  • Extruder motor (1x)

  • Bondtech pulley WITH the lock screw (1x)

  • Ensure you are using the correct motor, there is a label on the bottom of the casing. The reason is, each motor has different cable length.

  • There is a second spare lock screw in the package.

Ah, this is the other Bondtech not noted on the 5.E-Axis bag. This should be noted and also a special note above for the first Bondtech to use the one with no set screw.

Graham McIntyre - Reply

If you are upgrading from MK2S, remove the old extruder-gear/pulley

Michael Hermes - Reply

I got two equal Bondtech pulleys. There is no lock screw hole in any of them

Tor Andre - Reply

Hi Tor, please contact our support at info@prusa3d.com to get the correct one.

Jakub Dolezal -

I did. Got the correct pulley now. Awesome service :)

Tor Andre -

My BondTech pulley with the grub-screw (set-screw) had the grub-screw locked in place and the internal hex was stripped so I couldn’t remove the screw. Turns out the threaded hole wasn’t tapped quite far enough and it left a burr that locked the screw in place. It looked like they tried to remove it, only to damage the screw, but it was shipped to Prusa, anyway. I got Support in on this and they were great, telling me they would send me a replacement. I found an SAE (non-metric) Allen wrench (key) that was just barely large enough to get the screw out, so I contacted Support again to cancel that shipment of a new gear. I ran a tap through the threads, cleaning them up, and installed a new screw so everything is good now.

George Miller - Reply

I had the exact same problem as George Miller, but I manage to press a torx 6 in it and was able to tight it that way.

Martin Olesen - Reply

There is a flat part on the motor shaft, rotate it towards you. Slide the pulley on, note the CORRECT orientation. The screw must be facing directly against the pad (flat part) on the shaft. Slightly tighten the screw, the final adjustment will be done later.
  • There is a flat part on the motor shaft, rotate it towards you.

  • Slide the pulley on, note the CORRECT orientation.

  • The screw must be facing directly against the pad (flat part) on the shaft. Slightly tighten the screw, the final adjustment will be done later.

  • Don't press the pulley against the motor. Leave it on the very top of the shaft, see the picture.

  • Before moving to the next step, rotate the pulley 90-degrees clockwise ( the lockscrew will be facing to the left).

This step and picture should be revised to show the motor shaft flat and pulley rotated 90-degrees clockwise (set screw facing to the left, in the current picture). In the orientation this step requires currently, you end up being unable to access the set screw in the next step without turning it.

Guido Kimble - Reply

Hi Guido, good point. For now, you can rotate the shaft even if assembled in the extruder body. Use pliers.

Jakub Dolezal -

Came here to say the same thing. This step seems to imply the orientation of the shaft matters, but then has us align it 90 degrees off from being useful.

Zachary Loafman -

+1 yes, an additional image of the rotated gear would be helpful.

Gene Dahilig - Reply

I find that you can rotate the shaft-with-pulley when mounted inside the extruder body with just a finger, no need for pliers. (I’m twitchy about scratching things, I guess.)

steve hix - Reply

Find in the package two M3x30 screws and insert them into the holes. Before mounting the motor, ensure the second translucent washer is still on the   top M3x30 screw.
  • Find in the package two M3x30 screws and insert them into the holes.

  • Before mounting the motor, ensure the second translucent washer is still on the top M3x30 screw.

  • Mount the motor on the extruder body as shown in the picture, double check the proper orientation of the motor cables.

  • Tighten both screws firmly.

  • Tighten the screw, but only slightly, keep in mind the idler must rotate freely.

It's easy for the outer nylon washer to fall off when doing the steps between step 10 and here. Maybe put in the other 2 30mm screws first? Or at least note here to make sure the nylon washer is still in place.

Graham McIntyre - Reply

Thanks Graham, note added.

Jakub Dolezal -

I agree with Graham, the outer washer from stem 10 might be moved to step 13 to avoid losing the washer each time the piece is rotated.

Carlos Rusconi - Reply

It doesn’t seem like there are too many threads that catch the stepper motor for the screw for the idler.

Ira Schonfeld - Reply

It says the idler must rotate freely. I assume that means you can “close it" so it fits inside the extruder body?

Even with the screw loose it feels like it's bumping over two or three ridges as the idler moves over the extruder body.

Jeff Spencer - Reply

Hi Jeff, the idler must be able to move a bit, because when you insert the filament it will push the idler a bit out. However, without the filament inside, the idler should be “closed fully” (aligned with the extruder body).

Jakub Dolezal -

Doesn’t make a huge difference, but this section deviates from the “Please prepare” step that the rest of the guide does.

Evan - Reply

Hi Evan, thanks. I'm aware of these steps and will “correct” them soon.

Jakub Dolezal -

I think the pictures would be clearer if they included the idler assembly we mounted in step 10 (unless I’m missing something). It made me scratch my head at the orientation or wonder if I was missing a part.

Zachary Loafman - Reply

Oh, I just caught that the idler was “tucked in” in the pictures. My parts didn’t initially rotate freely that way so I didn’t try it.

Zachary Loafman -

Don’t forget to take out your nut holding the plastic piece before you screw in if you read the comments earlier!

Erin Baker - Reply

The idler door doesn’t fully close. The two Bondtech pulleys, even with the teeth engaging, don’t allow it. With some force, I can push the door to align with the extruder body, but that doesn’t sound right and is probably hurting the bearings in the idler pulley, which spring the door back open again. There are about four layers of idler door print material “sticking out” of the body. The M3x30s and their springs will probably exert a similar force as I can apply myself, but with Jakub’s above reply that “without the filament inside, the idler should be closed fully”, I’m not sure if I should just proceed.

Christophe Lermytte - Reply

In the forums, people stated that the door does not need to be fully closed and pointed me to the picture in step 24, which indeed seems to agree with that.

Christophe Lermytte -

Hi Christophe, you should be able to fully close the “door” (idler), however, slightly opened is still ok. Most important is to have the filament correctly flowing through the Bondtech gears.

Jakub Dolezal -

Open idler fully to have direct access to the pulley. Use a piece of 1.75 mm filament (from the spool) to align the pulley with the openings for the filament (see the picture). Arrows only indicate the direction.
  • Open idler fully to have direct access to the pulley.

  • Use a piece of 1.75 mm filament (from the spool) to align the pulley with the openings for the filament (see the picture). Arrows only indicate the direction.

  • Adjust the pulley and tighten it with 1.5mm Allen key. Use reasonable force as you might damage the thread.

  • When ready with the alignment, please remove the filament.

Adjusting the pulley and tighten it with 1.5mm Allen key failed as both Allen keys stripped at very low force. I used my own.

Valentin Bulbuc - Reply

Same here, the included allen wrench is not working. Had to use my own.

Alexander Buschek -

Have to agree with ++Valentin Bulbuc++ 1.5mm Allen key supplied is not adequate quality. Allen key stripped at very low force ++Jakub Dolezal++ , A change of supplier is easy an fix for future customers considering Prusa kit QUALITY is key to sales.

PaulHarris -

Do we remove the filament peice after? I’m just finding out I need to remove it to insert the e3D hot end later on

Alex Wilkie - Reply

Hi Alex, yes please. Remove the filament when done with the alignment.

Jakub Dolezal -

It would be nice if there were more pictures showing the feed path of the filament from other angles.

Gabe Yoder - Reply

Hi Gabe, from these pictures you can see most of the “filament path”, other angles always cover something. What issues do you have with the aligning?

Jakub Dolezal -

Agreed, like a back angle where the filament sensor is.

Erin Baker -

The black pieces of extruded plastic included in the box are NOT filament. I fiddled with how to get these to route through for a little while before opening my box of actual filament. Adding a note here wouldn’t hurt to have someone else avoid my mistake.

Joe

Joe Pighetti - Reply

This threw me off as well. I was about to get a drill before I read your comment.

Travis Howard -

Hi Joe, that is why it is said to use a filament from the spool.

Jakub Dolezal -

For clarity, you might mention that a piece of orange filament is used in the picture to show the routing, and the green arrows are parallel to the correct path.

Bill Magley - Reply

Please just include a 100mm piece of filament in the bag for the step. Save so much time.

phr0ze - Reply

This. I was surprised I had to pop the filament in this step.

Zachary Loafman -

Exactly. Reluctant to break the humidity seal of a new filament that will not be used right away and I haven’t got my dry storage boxes fixed yet… 100 mm of orange filament would be nice in bag 5. E-AXIS. I have the black version and black filament is harder to see inside the black parts.

Anders Permats -

Agree it’s hard to see where to insert the filament from the back … a top view with an arrow of where to insert would help. I see now it inserts right next to the sensor.

Rich - Reply

In my case the filament (yes, from the spool) didn't fit through the small hole, it got stuck. So I widened it with a 2mm drill bit. I hope that's no problem?

Tako Schotanus - Reply

Hi Tako, small diameter increase should be fine.

Jakub Dolezal -

At the end, remove the filament, close the idler and look through the “exit” hole to check alignment.

Etienne van Ballegooijen - Reply

The grub screw socket is EXTREMELY shallow!

Allen key failed to turn the grub screw, and I noticed the Allen key was slightly worn / rounded / deformed.

I used the second Allen key, which was in better condition, and it worked slightly better.

I didn’t think to blame the Allen keys, but rather thought I had stripped the grub screw.

I’ll go back with an Allen key from my toolbox and try it again.

Andrew E. Mileski - Reply

Hi Andrew, there is a spare lock screw in the package (bundled with the Bondtech pulleys) ;)

Jakub Dolezal -

My grub is stripped and I can’t even get it out

Craig Bennett - Reply

I got it out after a few hours of trying. I about damaged my hands doing it

Craig Bennett -

I had the same problem as Craig. I didn’t think that I tightened it too much, but clearly I was wrong. Given how shallow the inset is on the screw, it doesn’t take much to round out the inside. It took 30 min of effort with multiple different allen keys (both mm and SAE) to finally get a grip on the inside to get it out. I thought that I was going to need a new extruder motor and hobbed gear.

TrinityEllis - Reply

For the following step, please prepare: M3x40 screw (2x) Extruder spring (2x)
  • For the following step, please prepare:

  • M3x40 screw (2x)

  • Extruder spring (2x)

  • Assemble springs on both screws, see the second picture.

  • Close the idler, so the screws can reach it.

  • Place both screws into the Extruder body and tighten them. The screw's head should be almost aligned with the printed surface.

Are we supposed to close the idler first here?

Neal Tibrewala - Reply

Hi Neal, yes you must close the idler first as the screws must reach nuts inside the idler. Step instructions updated.

Jakub Dolezal -

So what distance should the screws be tightened for optimal grip/release? Almost flush? Is there a more scientific method to this, or does it not matter that much.

Douglas Shelfoon - Reply

Hi Douglas, on MK3 align the screws with the surface of the printed part. We've improved the design this way, so no special measurement is needed.

Jakub Dolezal -

Impossible to tighten even slightly on the part i received, the idler had no thread and the screw/bolts just slip though….

It would be better to use a metal nut here since the printed part was useless

Tom - Reply

Hi Tom, You might have missed step 3 first picture? There should be nuts in the idler.

Orne Brocaar -

Thanks Orne,

Just now saw the 2 holes for the square nuts as you said, so it was my fault being stupid :(

Great news though, I can continue building now :))

Tom -

Is this supposed to mean align the top or bottom of the screws head? I'm now assuming you mean bottom. If so, can you revise it to say “The bottom of the screw's head should be almost aligned with the printed surface.” ? I originally assumed it to mean the top of the screws head and it's been causing me issues with my filament breaking for days because my gears were way too tight. It's actually hard to tell from the pictures how is lined up.

Andre Fowler - Reply

So top or bottom of the head? If I set it to the bottom of the head, the spring has almost no tension.

Ira Schonfeld - Reply

I was not sure either. So I put the filament back in again. While tightening the screws I push and pulled on the filament until it feels right. OK, not really a scientific method, but it turns out I had a good grip with the screw head TOPS just above the printed part. Hope I’m not wrong, let’s see later :0

Quentin -

Thanks Quentin, that helped me as well putting the filament back in to see what this area was doing. Had some good tension on the filament, but could move it back and forth - so now I understand a little better what’s going on in there, and so far it seems good. Sounds like it’s adjustable for various filament widths, so good to go on for now.

Gregory Thomson -

The screws “extrude” from the back as two small 2-3mm bumps post the idler - is that what expected?

Peter Larsen - Reply

Any closure on whether it’s the top or bottom of the screws’ heads?

I did closer to the bottom and seem to be getting good tension on the filament.

Evan - Reply

Hi Evan, the screw heads should be almost aligned with the surface, but this is something you will adjust during the prints and also in case you buy filament with larger diameter (larger tolerance), you might need to adjust it again.

Jakub Dolezal -

It might be good to remind people that the back side of this part looks similar to the correct side (a hex opening over two holes) so if you aren’t paying attention and accidentally put the screws in the wrong side you can get the screws compeletely past the threads such that they can’t be removed without destroying the 3D printed part.

Don’t ask me why I know this……

(I had a friend re-print me the part, after a 30 minute freak-out)

Brian Bishop - Reply

Same happened to me. Is it possible to remove the screws without damaging the print?

Lakshman -

My build has ground to a halt. The shoulder of the smooth shaft is stuck on the square inside the idler part. Not sure of function of this square but. Is the m3/40 supposed to be secured against extruder body?

Steven Comisso - Reply

D'oh. Just saw my mistake.

Steven Comisso - Reply

As I have it assembled now, the idler turns in opposite direction of the motor. I cannot figure out how this should work?

Georg Zueblin - Reply

Hi Georg, can you record a video? Post it in section “Answers” (see top of this page). At this step, there is no movement needed, so I need more information.

Jakub Dolezal -

Instead of telling us at the start to put the nuts in then. Why not here? If the nuts are screwed in, then they fall out super easily

Craig Bennett - Reply

This is the first step I did backwards - definitely needs a callout to ensure users are entering the screws from the correct side of the idler. Also the slots that hold the square nuts are too loose/sloppy - one of my square nuts is rotating in place. I have to stick a small allen key in from the side to hold the nut from rotating as I tighten the screw.

Connor H - Reply

I did this too, and unfortunately, tightened one screw so the nut was past the threaded part of the screw. I thought I was never going to get it backed out because the square nut was slipping, but your post gave me the idea to trap the nut with something thin. The smallest allen key proved too big, but I ended up trapping a paper clip in one side as it turned, and then I was able to get enough purchase to re-thread the screw and back it out.

Definitely think this step should call attention to the fact that the part needs to be turned over.

JDR -

Take two M3nS nuts from the package and insert them in the slots, all the way in. Check proper alignment with the 1.5mm Allen key.
  • Take two M3nS nuts from the package and insert them in the slots, all the way in.

  • Check proper alignment with the 1.5mm Allen key.

Minor nit, I missed this step and inserted the nuts after the hot end was attached. Maybe put a picture of two M3nS nuts with green arrows, like is done in the rest of the manual? There is enough information to figure this out, but having the extra cues would help.

timcdoc - Reply

Hi Tim, this step will be updated. Thanks for the suggestion.

Jakub Dolezal -

Yeah, when 95% of the rest of the manual has a “prepare X, Y, Z” step it throws you off for the 5% of the time it doesn’t.

Evan - Reply

Hi Evan, I will update these steps soon.

Jakub Dolezal -

For the following steps, please prepare: Extruder-cover (1x)
  • For the following steps, please prepare:

  • Extruder-cover (1x)

  • M3nS nut (1x)

  • M3n nut (1x)

  • M3x25 screw (2x)

  • Insert both nuts in the printed part.

  • In case you can't press the M3n nut in, don't use excessive force. Take M3 screw thread it from the opposite side of the printed part, as you tighten the screw, it will pull the nut in. Be careful not to break the printed part during tightening.

In case you can't press the M3n nut in, don't USE excessive force.

Keith Manley - Reply

Thank you Keith, corrected.

Jakub Dolezal -

I cannot manage to fit this in whatsoever. The screw trick does not seem to be working whatsoever in getting the m3n nut in. Is there any better advice for this?

Kyle Campbell - Reply

EDIT: It eventually worked after brute force involving a rubber mallet.

Probably not the best idea though…

Kyle Campbell -

Hi Kyle, the “screw trick” should work always, but you need to ensure three things:

1) the thread is on the entire screw

2) there is nothing blocking the nut from going down

3) nut is aligned with the shape of the slot

Jakub Dolezal -

I had a bit of a problem getting the M3nS (square) nut in the hole. It was really tight and I had to poke in the hole with a small Allen key and also a bit with the Phillips screw driver to clear it just enough to be able to push the nut all the way in using some force pushing it in with the screw driver.

Kari Söderholm - Reply

Hi Kari, we are checking the printed parts before shipping them to you. However, sometimes it might happen there are some residues, which are blocking the nut. Use the smallest Allen key, to check it out and if needed clean them.

Jakub Dolezal -

The instructions say to pull the M3 nut in with an M3 screw, but the shank of the M3x25, used in this step, is too long to get force on the nut against the printed part. I recommend using any of the full-thread M3s from the package, such as the M3x10, in order to get the right pull-in.

Trey Hilyard - Reply

I think there is something wrong with this design of this step. I’ve dealt with “the thread trick” already, and I’ve had to use “excessive force” because the product does not meet the specifications otherwise. I just spent an hour on this step and I am not done..

The nut is supposed to bottom out on the arm, and that surface is rough extruded surface. Of course that interface is going to cause problems! Then you have the corners to deal with and other little bits of extrusion will get in the way.

Prusa should avoid this fastening method at all costs.

Even when I take the nut out, I can see only a few threads of my specified M3x18 screw making it through to the nut area. I’m seriously tempted to take a drill to the whole thing. If they’d just given it a little tolerance by making the screw a 20 instead of an 18 it would have probably eliminated all problems.

Really the arm should just be solid with a slot in it like so many other pieces are.

Ben Ruppel - Reply

Take the E3D hotend and place it inclined into the Extruder body. Make sure the white PTFE tube fits in properly. Insert the hotend into the Extruder body, see the picture.
  • Take the E3D hotend and place it inclined into the Extruder body. Make sure the white PTFE tube fits in properly.

  • Insert the hotend into the Extruder body, see the picture.

  • Make sure the hotend is fully seated and the upper part aligned (almost in contact) with the surface of the printed part.

  • Note the CORRECT orientation of the hotend.

  • Be VERY CAREFUL with the hotend wires from now on, you can damage them.

The PTFE tube insertion should be its own step prior to this one, please.

RWReese - Reply

Nevermind, please.

RWReese - Reply

What should be another VERY CAREFUL point here is to pay attention to the hot end being inserted ALL the way. Pay close attention to the final picture and how far in the hot end is. Mine was not in all the way. It went together and all was good until the XYZ Calibration. Yikes! Took 2 weeks to finally figure out what the heck was wrong. Finally got it thanks to the build forums.

Mike Kwiatkowski - Reply

You should perhaps mention that the white tube will need to bend a bit for you to be able to get the hot end all the way in.

Andreas Sjolund - Reply

The manual says, “Push the hotend into the Extruder body, see the picture”. What it should say is “Insert the hotend into the Extruder body so it fits around the collar in the Extruder body. This will make the bottom of the hotend even with the Extruder body.”

This little misstep on my part caused 10 days of total frustration because when I ran the XYZ calibration it always failed with the message “XYZ Calibration failed, check the axes”. So that what I did but it had no relationship to the axes. It was a hotend location problem.

E Duane Rose - Reply

Hi Duane, I'm aware of this and we are already working on a new design, but you are right. The instructions will be updated ;)

Jakub Dolezal -

I had to take mine appart after it failed at calibration. So making it easier to fit the extruder body and cover to make it easier to fit in the correct position would be a massive improvement.

Martin Wolfe - Reply

Ditto. Thankfully, it only took hours to fix and not days. I realized there was a problem after I attached the the wire routing when the nozzle was loose and rotating freely. Still, it should be more difficult to snap on the extruder cover if the extruder is not in the right position. It’s never fun disassembling a part immediately after spending an hour assembling it.

Mahir Abrahim - Reply

It was ten days for me as well. After failing XYZ calibration, I noticed I was repositioning of the P.I.N.D.A. probe a lot. Then when I found that 6-8” of filament disappearing inside the extruder. I decided to run the extruder motor until the nozzle started to extrude filament or something physically come out. The nozzle was what came out. I then knew, I needed to open up the extruder block. Went back to the online page for the extruder nozzle assembly and found the same error codes I had by your comments. I then remember being unsure of putting this part together. I ended up taking out the PTFE tube from the nozzle assembly and reinserted that first into the plastic body case and pushed it into the hole and up to the Bondex gears. I then inserted the extruder nozzle over PTFE tube and then was able to place the aluminum nozzle easily into place. I put the unit back together and the printer calibrated then properly.

Thanks for your comments it make the difference!!!

Frank De Abreu - Reply

Is the Hotend from the MK2S (which has my Olsson ruby) the same as the one in the MK3 upgrade? I’m trying to avoid changing the nozzle

Thanks, Stuart

Stuart Kurtz - Reply

Contacted Support. It is different a Voltage. ?24V vs 12V. Installed ruby prior to assembly> I’ve realized what is ultimately needed is a quick change nozzle system to accommodate different sizes for different print types. The current nozzle change system is too difficult to make swapping a print nozzle a regular experience .

Stuart Kurtz - Reply

Hi Kurtz, there are some significant differences, you have to use the MK3 hotend.

Jakub Dolezal -

I made the same mistake of not having the hotend flush with the extruder body. I didn’t realize I made that mistake until I went to calibrate the PINDA probe and realized the hotend was sticking out way too far. Took me about 30 minutes to take apart the extruder and install the hotend correctly. Getting the hotend to fit right wasn’t easy, I had to bend the ptfe tube just the right way to get it to fit. I may be oversimplifying the problem but it would be nice if the hotend could only fit in the extruder body only one way. Other than this one problem the assembly of my printer went smoothly and the printing is perfect.

M Goddard - Reply

Is our E3D V6 supposed to arrive without the blue collet clip? If you look at Step 18 on their assembly instructions, this part is included. I am only seeing the black collet and PTFE tube on my V6 here. https://e3d-online.dozuki.com/Guide/V6+A...

Todd Scott Anderson - Reply

I found a decent clip on thingiverse. Also I removed the tube and made sure everything inside was clean. the loose collet’s teeth had made a couple little ptfe strips and the bottom of the tube wasn’t exactly square. Removed the fluff and fixed the bottom.

The initial collet ring’s dimensions were a bit flimsy so I scaled it X, Y, Z : 0.95, 0.96, 1.2

https://www.thingiverse.com/thing:127662...

Todd Scott Anderson -

Hi Todd as far as I remember the collet on E3D V6 was always black. Was your missing completely?

Jakub Dolezal -

It will be extremely helpful if you guys add the specific measurement for the PTFE tubes both for the hotend and the one for the sensor cover they can get easily damaged and you will need to replace them but is hard without the proper measurements.

Cesar Lopez - Reply

Had to come back to this step after seeing the same “Calibration failed, check axes" error message. Double check the hotend/PTFE tube is way up there, y’all.

Taylor Mills - Reply

The problem is that the hotend can be fitted perfectly in two positions, but only the upper one (as mounted on the axis) is the right one. The instructions fail to show the good and the bad position. Like all the guys above I got stuck at the calibration procedure and had to go back to this step.

Georg Zueblin - Reply

Inserting the PTFE tube took more force than I was comfortable with applying.

After only the first attempt, I noticed the chamfered top of the PTFE tube had been deformed.

It took several attempts before I finally went YOLO and pushed it in.

There has got to be a better way to do this!

Andrew E. Mileski - Reply

Well the tube has to sit in tight, that is why the insertion takes slightly more effort than the other parts of this printer.

Jakub Dolezal -

To make sure my tube was fully in, I opened the idler door and could see the tube inside within just a few millimeters from the idler itself, which seemed proper to me. Is there any reason having this picture/step shouldn't be included in this assembly

343 Guilty Spark - Reply

The hot-end PTFE tubing appears to be 45mm long. My hot-end overheated, causing the filament to become stuck in the tube, and I had to disassemble the extruder enough to remove it, then clean-up quite a mess. The PTFE tube was replaced but the hot-end needed to be disassembled, the heater block cleaned and the nozzle replaced. Not what I expected from a 5-day old printer. The original PTFE tube I removed had been stretched due to the heat, and it measured 50mm in length. I started with a replacement tube of the same length, then cut it down after trial and error assembling, ending up with 45mm. I seem to remember during my printer assembly that the length of that tube was mentioned but I couldn’t locate that information again. Hope this helps future assemblers.

George Miller - Reply

Hi George,

I recently placed all the PTFE tubes in one place https://help.prusa3d.com/l/en/article/nt... and correct length for the MK3 PTFE tube is 50 mm.

Jakub Dolezal -

Would it be possible to add pictures from the top?

Brian Dobson-Lewis - Reply

Hi Brian, by the “top” do you mean to see the nozzle, or the other side?

Jakub Dolezal -

it’s ok to the cables of the thermistor to be touching the heat block? mine are touching but i’m afraid to break them if i try to move the cables away

Gustavo de León - Reply

Rotate the extruder as shown in the picture. Take the extruder-cover and place it on the extruder body. Both printed parts must be in direct contact. Using M3x25 screws tighten both parts together.
  • Rotate the extruder as shown in the picture.

  • Take the extruder-cover and place it on the extruder body. Both printed parts must be in direct contact.

  • Using M3x25 screws tighten both parts together.

  • Ensure again the hotend is properly assembled. The surface of the heatsink (part of the hotend with cooling ribs) must be aligned with the surface of the printed parts. See the last picture.

On the last step of this part, using the 2 screws to tighten both parts together, I accidentally got the screw and nut cross thread. Now, the nut just turns in the 3D printed part and they’re stuck. I think you should use a longer nut or better quality nut so they don’t get cross thread. Like a coupling nut.

Bob - Reply

With the hot end in and the two parts together, the outside part rocks, as of there is some interference. I had to clean up a bit of the inside of the extruded cover and had to use a 30mm on the right side. A 25 mm wouldn’t even contact it

Steve Worcester - Reply

I agree. M3x25 was too short on that right side. Had to go with a 30

Christopher Tilley - Reply

M3x30 here, too.

RWReese - Reply

M3x25 worked for me.

David Beach - Reply

I also had to use 30mm, the 25mm would not grab the nut

Dennis Sladek - Reply

25mm were ok for me.

Andreas Sjolund - Reply

I got the same problem as Bob. The 25mm screw started to go cross thread and the nut started rotating in the printed part (as the nut wasn’t completely straight) without tightening. I was luckily able to get it out by pushing on the nut with the Phillips screw driver to keep it from rotating while unscrewing the screw. Then I used a 30mm screw to get it more easily on the correct thread.

25mm screw might work ok if you get it perfect, but I think it’s just easier to use a 30mm screw here and even putting in the screw first and then the nut it was easy at this point. Still the screw is totally inside the printed part. I would suggest switching to 30mm screw here for more foolproof assembly.

Kari Söderholm - Reply

Guys, thank you for the feedback. 25mm screw should be enough, but we will adjust the design for easier assembly.

Jakub Dolezal - Reply

The last statement in RED is a important point. Be sure to make this check as you assemble the extruder housing. if your installation is incorrect it will show up as an axes error when you do the XYZ Calibration.

E Duane Rose - Reply

Thanks Duane for your comment. I read it and quickly realized I needed to back up and reassemble the Extruder Cover. Removing the E3D Hot End took quite a while because the white PTFE tube was stuck. My solution was to enlarge the hole for the PTFE tube and then use a Dremel tool to widen the interior of the Extruder Cover so the two halves would fit around the E3D Hot End without rocking or stripping screws.

Bill Waring - Reply

The M3x25 screws worked for me. I actually had hard time positioning the Extruder Cover around the Heat Sink, it all looked misaligned. Eventually I inserted the two M3x25 screws all the way in into the Extruder Cover, and using them as guides towards their nuts managed to align everything properly and to tighten the two screws (hope the later Calibration step will pass OK!). It is a rather delicate step…

I read in the messages above that two of you had problems with “misaligned” nut. Maybe it helps to someone reading this, but I discovered one “M3” nut that would not fit., no way I had problems with it, tried several M3 bolts, it would not work. Then I took it out and tried it with several M3 bolts just to test it, nut and bolt only. None worked. I believe that nut is not Metric! It got somehow mixed in, and I was fortunate not to force it and create a bigger problem with some part…

Alan Rusyak - Reply

M3x25 worked for me, eventually. Biggest issues were:

1) Realizing just far down the hole those nuts need to be placed. It helps to pre-thread the two screws into the cover as far as possible, and checking the depth the head CAN reach. Hold the cover to the side, and you’ll see the screws DO stick out approx 1/4”, which is easily enough to catch the captured nuts IF they are also sunk as far in as they are supposed to go. Not easy, but it works.

2) Also, for me, I needed to realize that we’re not trying to catch BOTH of the square nuts on the left side (looking at the photo above), only the closer one. I assume the farther one has yet to be used, but will be soon.

Kalani - Reply

I’m worried about the hot end wires bouncing around while they are still bundled. Is this a good time to cut the zip tie holding all the wires in a bundle, or is it safer to leave it tied up? for now? (I realize the zip tie holding the two hot wires should probably stay)

timcdoc - Reply

Just an idea… once I had finished this assembly, I noticed that I had bent the delicate pins of the the filament sensor. Would it not be a good idea to include a little plastic cover that can be slid on to protect the pins at this fiddly stage?

David - Reply

Here is how I captured the nut: use a longer screw on the nut side, but only grab 2 threads. Use that screw to push the nut against the M3x25 coming from opposite dir3ction until the 25mm grabs the nut, then back out the screw that is barely attached, then finish tightening the 25mm screw.

Rich - Reply

Great tip, worked perfectly thanks.

Shaun Collins -

To get the M3x25 to work on the right side, I first used an M3x30 and by tightening that it pulled the receiving nut in all the way inward … I then removed the M3x30 and was able to screw in the M3x25.

Gerry P - Reply

The left side fits perfectly with the M3x25 but the right side does not go all the way. Seems like its block after 3/4 of it… what do I do??

Pablo Traversat - Reply

M3x25 fits fine. When you put the nut in (Step 6) it says to put a longer nut in from the other side and tighten it up to pull the nut further in.

I used an M3x18 and that was enough to get the nut all the way in. If your M3x25 is not reaching, give that a try.

SteveP - Reply

Nut traps for M3 nuts are the bane of my existence. Had the same issue on the Mk2. Some nuts just don’t stay put…

Cristian Sandu - Reply

I also needed to use M3x30s to get the nuts to catch.

Gene Dahilig - Reply

2 x 25mm worked fine…

Martin Wright - Reply

This is another step where I had a nut that was not perfectly straight in the hole, the screw got cross-threaded, and the nut started spinning in the hole. I will use more care in the future, but some of the suggestions in the comments such as using a M3 standoff rather than a nut and/or using a longer screw do seem to be useful.

Harold Toler - Reply

The cool-end fan side, top edge, doesn’t meet perfectly. There is a gap.

The pictures here seem to show the exact same defect.

It is hidden behind the fan, so it doesn’t really matter, but it shows that a part redesign may be required to increase clearances.

Andrew E. Mileski - Reply

I have this as well. Not sure if it's gonna be an issue yet or not, but at there's a sliver of comfort knowing someone else made similar note

343 Guilty Spark -

I also had a challenge inserting the M30x25mm screw on the right side because it wouldn’t grab the nut. I found that the nut wasn’t seated correctly so what I did is I took a M30x40mm screw instead, screwed it in all the way and this allowed me to fasten the nut to the end of the longer screw which when tightened, pulled the nut in place. Then I removed the 40mm screw and put the M30x25mm back in and it worked perfectly.

Ben - Reply

I have a similar small gap at the top edge near the cool-end fan. It is about 0.75 mm. Did it work out OK for you all?

TrinityEllis - Reply

For the following steps, please prepare: M3x18 screw (6x)
  • For the following steps, please prepare:

  • M3x18 screw (6x)

  • Left hotend fan (1x)

  • Front print fan (1x)

  • The left hotend fan has two sides, but the side with sticker must be always facing the hotend (not visible when the fan is mounted). Otherwise, the cooling won't work properly.

  • The left hotend fan (Noctua) can be also in a black colour without the rubber corners, other hardware parameters are the same.

Bolting on the Front print fan took me a lot of time because I could not get the nut inserted far enough (so the 18mm screw was too short to ‘reach’. 10 minutes of careful scraping/cutting and pulling later the connection was established ;-)

Jeroen - Reply

I suggest using a m3 washer on each m3 screw holding in the front print fan to avoid cracking the casing of the fan at mount points.

Natalie Crandall - Reply

Hi Natalie, thanks for the suggestion. For each fan assembly there is a warning regarding cracking the plastic cover while tightening. If you follow the instructions, you will be fine :)

Jakub Dolezal -

I’m guessing this is a good time to unroll the fan wire, but maybe a note saying it is, or it isn’t.

timcdoc - Reply

I would recommend taking a second to check the condition of the terminals on both of these fans. My print fan had a burnt and broken connection to the yellow terminal and I didn't find out until I put everything together and did cable management.

Ryan Latimer - Reply

Hi Ryan, fans are tested in our factory before shipping, but I forwarded your findings to my colleagues. Please contact our support for a replacement (info@prusa3d.com).

Jakub Dolezal -

My fan is missing one of the brown rubber grommets. It’s on the outside, so I don’t think it should make a difference with noise or vibration.

Mark Tellier - Reply

Don’t overtighten the screws securing the front fan, it is easy to, I think I did and it failed the first self test when complete… or there was another problem I didn’t know about, anyways, that was the only issue I had after completion and printed my first part shortly afterwards :-) , well happy…

Martin Wright - Reply

Same here with the missing outside rubber grommet on the hotend fan.

TrinityEllis - Reply

Place the Extruder on the side and guide the wires from the motor in the slot. Place the Left hotend fan on the Extruder. The cable must be placed in the top left corner, see the picture. Note the correct orientation of the fan. The sticker has to face towards the hotend!
  • Place the Extruder on the side and guide the wires from the motor in the slot.

  • Place the Left hotend fan on the Extruder. The cable must be placed in the top left corner, see the picture.

  • Note the correct orientation of the fan. The sticker has to face towards the hotend!

  • Insert M3x18 screws and tighten them slightly.

  • Now, tighten ALL screws, but on a diagonal. After tightening check, the fan can rotate freely.

  • DON'T tighten the screws too hard, all parts are made of plastic and you can break them.

turn the fan so the cable go out to the rear of the carriage

Heiko Schultz - Reply

Hi Heiko, thanks instructions were updated.

Jakub Dolezal -

Not sure where to route the extruder motor wires after they’ve been routed through the slot, as indicated in picture 1.  I currently have them running down the back of the noctua fan and in the slot so it can be routed behind the extruder and wrapped.  In other photos the motor wires are not visible from the back of fan so I’m not sure if there was a step that I missed?

The wires are as snug as I can get them routed around the noctua fan but I'm afraid that they may come loose in time and make contact with the belt.  I think better pictures of the cable routing for the motor could help.  I’ll remove the noctua fan and see if there’s anything I missed.

Corey Dryja - Reply

I think I found the answer to my question and I may have asked my original question out of order.  It looks like there is a slot on the x-carriage that the extruder motor wires are supposed to run through that sits on the side of the fan.  This is not the slot that’s detailed in the steps below.

Corey Dryja -

In this step it calls for M3x18 screws for the Nactua fan. I didn’t like how in the second picture the screw that is inserted near the edge by the heater cartridge protruded. It was really close the thermostat wires. I replaced it with a M3x12mm. Later I will switch it to a M3x14mm for better anchoring. Prusa Team may want to look at that.

Donnell - Reply

Hi Donnell, thank you for the feedback. The design is safe and working if the printer is built according to the instructions. Longer/shorter screws might be working as well, but I can't guarantee it and also it will be extra screw size in the package. We tried to lower the amount of sizes across the entire build.

Jakub Dolezal -

Agreed. I understand the need to keep the part list minimal, and I agree with this. Perhaps this could be another place to have a square nut or hex nut there, as this seems to tap into the PETG part. However, I fear I may have overtightened here because I wasn’t sure how much to torque this screw. It seems it would be better with a metal to metal connection here instead of the longer screw nearing the hot end, as Donnell was saying. With a nut, perhaps a 10mm screw would be adequate and not come near the hot end.

Ben V -

The protruding screws were also unexpected for me, as every screw so far in the build has been of perfect length. Maybe a clarification in the instructions would be welcome.

Andreas Sjolund - Reply

You might mention these are plastic self taps….

Rich - Reply

Why is the cable location for the fan described as top left? As you face the fan it is more like bottom right. It would be nice to show a picture if it is intended to be close to the extruder motor wire bundle coming out of the groove.

Charles L Miksch - Reply

Hi Charles, if the extruder is mounted, then the cable is in the top left as described in the instructions.

Jakub Dolezal -

“Top Left” corner doesn’t really make sense when the extruder is laying on its side. Perhaps “The fan wire should be next to where the motor wire was just placed in a channel.” Especially since no image was shown from the side where the wire could actually be seen on the fan.

Dave S - Reply

Yes. This is much more clear than “Top Left.”

Brien C -

the raceway for the extruder wires over the fan is very small can you enlarge the raceway so we have more room for the wires. please.

vincent bartlett - Reply

1. The Left Hotend Fan I was provided with was black, not brown. Jakub, you might want to add to the instructions of this step that this is the same fan to avoid confusion if the Left Hotend Fans you’re providing with the MK3 kit are all now black and no longer brown.

,

2. Be extremely careful when tightening the M3x18 screws into the Left Hotend Fan. Unlike many of the other parts that you/we/I have tightened so far, you won’t get any sort of torque feedback when tightening these screws, other than the visual cue of them sinking right below the top surface of the fan. The screws will just keep spinning without any indication that they’re fully screwed in, and you’ll strip the plastic threads on the printed pieces below. Again, just screw them in until they’re down right below the top surface of the fan and call it good.

blueyes13@gmail.com - Reply

Rotate the Extruder as in the first picture. Mount the Front print fan using two M3x18 screws.
  • Rotate the Extruder as in the first picture.

  • Mount the Front print fan using two M3x18 screws.

  • DON'T tighten the screws too hard, all parts are made of plastic and you can break them.

Myself and at least a few other users have run into the self test X axis failure due to the fan or extruder wires slightly sticking out behind the fan where the extruder carriage will pinch these wires when it runs into the left Z axis bracket. It would be helpful to new users to show a closeup of how the fan & extruder motor wires need to be tucked into the slot that runs over & behind the fan.

Jason Livingston - Reply

not into the slot, the slot is fine for the extruder cable, but the fan wire is too thick.

the MK2(s) fan cable is without '''cable sheath''' and would fit into. To push both wires into the slot on the MK3 would result in high pressure to the wires.

I’ve guided them directly out at the back of the carriage.

At step 21 you can see the wire and the cutout at the fan

https://picload.org/view/drprorai/2017-1...

Heiko Schultz -

Hi Jason, cable management for extruder cables starts at step 24. It is shown you need to place the cable inside cable clip and then inside the slot on the X-carriage, but I will recheck this part again.

Jakub Dolezal - Reply

Yeah, but the problem is with how the extruder cable has to be positioned for step 28. It was not clear enough nor obvious enough how to put the extruder cable, and I ended up having trouble on the X Axis calibration too, I almost had to unmount the whole head to fix this.

Thelvaen Mandel -

the top M3x18 screw is too short. And no, there is nothing blocking the nut ;((

Guntor H - Reply

Hi Guntor, are both nuts properly installed? You can use longer screw to pull them closer and then replace with M3x18.

Jakub Dolezal -

I’m running into the same problem. Nothing blocking the nut. I did notice that it kept falling out between the step where you insert it and this step. I’ve used a longer screw to try pulling it in. I’ve used this screw without the fan to try pulling the nut in. Still won’t fit. The screw keeps turning, because it doesn’t quite reach the nut to lock into place. :-(

Jennifer Krull -

I Had the same problem. The M3x18 is just a millimeter or two too short. I went for a longer screw from the spares. Doesn’t look perfect, but should work perfectly.

Pål Driveklepp - Reply

I had to do the same

Craig Bennett -

Ditto. Spent half hour on the problem, resorted to a longer screw. If it impedes something down the road, out comes the Dremel with a cutting wheel. First unsolvable problem not following the instructions. Find these comments invaluable. Onward.

Gary Shumway -

Same problem with the top m3x18 bolt (or screw if you prefer), it is too short - I used a 20mm one I had for another project

Chris Tipney - Reply

I had today the same problem - i fixed it with a lighter - just screw the nut (in the sparepart) on a screw and heat them a little bit (not to hot!!!) and pull them into the hole (just a little bit) - thats works perfect ;)

Greetings,

Max

Max007 - Reply

thanks for that (frightening) tip! works! better would be a 20mm screw!!!

Christoph Stahl -

Max, I was going to do the same thing but resorted to just using a longer screw. Figured less likely to screw something up…or more likely in this case.

Gary Shumway -

I had the same problem with the one screw seeming too short. After I tightened a 20 mm screw in, I noticed there was about 2 mm sticking out and I was able to take it out and put the 18 mm one in. So, I t is just barely long enough and the nut has to be completely seated which I wasn’t able to do without the slightly longer screw to tighten it in.

Ross Stenersen - Reply

Use long screw, tighten it, remove and replace with correct one works for me.

Jan Tomek - Reply

I did the same as Jan above, worked great

Alistair - Reply

The seam on the fan popped open on me when I tightened the screw down. No big deal but now the fan has a little crack on the mounting hole. A bigger screw that overhangs the fan mounting hole a little more would help with that, or a washer. I think the M3 head is almost small enough to fit in the mounting hole so it exerts a side force on the fan housing when tightened. I was not over-tightening, it popped pretty early. Fortunately the fan requires very little force to hold it on so even with the crack I was able to loosen the screw a bit and still keep it in place just fine.

A warning to tighten very gently would be good.

Bryan Jackson - Reply

Be careful out there. I over-tightened the screw on the “crows nest” which cracked the very delicate fan housing. Just a small crack, though and it’s still quiet as a mouse FWIW.

Andreas Sjolund - Reply

The M3x18 screw is long enough. Use the top of a longer screw to press the nut in while screwing in the M3x18.

Edwin Martin - Reply

it was exasperating getting this 10mm screw in the top part fan shroud. I tried the heating method, that didn’t do anything, but then I used a longer one and wrenched it down really hard, then was able to use the 10mm screw.

Brian M - Reply

Also cracked one of the fan mounting points, but a bit of super glue (and an even lighter touch) worked fine. I agree with earlier comments that a washer might be a wise choice on both of those screws.

Bill Magley - Reply

I had to use a M3x25 screw to help set the nuts in the printed part (with the fan in place), then the M3x18 screws were able to reach the nuts properly.

Paul Bowers - Reply

I had to use a separate small screw to get the nut on the arm in tight so the screw would reach it to the fan mount hole (top one). It’s a very tight fit and the screw will not reach unless you ensure the bolt is all the way in and very tight,

Peter Larsen - Reply

18mm is too short. A 20mm from old MK2 fan worked for one and used a spare 25mm for the other deeper one.

Ray Ackley - Reply

Thanks for the tip Ray! I checked my spare bag from my MK2 and found a 20mm screw. It’s much better :)

Gael Lafond -

I 2nd Ray’s comment. Was unable to get an 18mm into the “arm” nut. Using a 25mm for the meantime…

Woger Dog - Reply

Agree with all who commented that 18mm screw is too short on upper left corner of fan, especially with warning about not tightening too much or risking cracking the fan housing. I’m using extra 25mm screw for now. May use cutoff wheel on my Dremel later if it’s an issue sticking out.

Dave Templeton - Reply

I over tightened the screw and it split the fan mounting tab a little. It seems the fan mounting hole is over-sided for the screws provide leading to this issue.

Luke Davis - Reply

Same problem as others : but different solution : with the (black) front print fan, the M18 bolt furthest from the extruder motor, wouldn’t catch on the nut. The nut we’d noticed was quite loose previously, (it dropped out when turning the assembly back and forth), although was not proud of the surface, so we’d presumed it was in far enough. We’d tried pushing it in with a flat head screw driver : We tried pulling with a longer screw, [having first removed the fan] : but that didn’t work.

What worked in a nicely controlled fashion was :

We put another hexagonal nut on top of the one that was apparently flush with the component surface, then used Maun flat parallel jawed pliers to drift it into place. by squishing the (proud) extra nut against the opposing face of the plastic arm the nut we wanted sunk into beautifully. Throughout the build we have used our Maun (200mm) parallel pliers time and time again, whilst reading comments from people about it being difficult to drift things into place.

Jonathan Histed - Reply

It took me nearly 1 hour just to get the 18mm screw to catch the nut. Nut kept popping out, even after I would tighten it using a longer screw. I finally just pushed my thumb against it, after tightening it with a longer screw, and it caught.

Jeff Gannon - Reply

I also had a problem with the front print fan 18mm screw. I used a small set of files (or even sandpaper) and ground off approx 1mm from the plastic screw hole ledge, effectively making it the depth less shallow for the screw to extend. I kept the original screw and it was able to catch the nut on the opposite side and easily pull it into place.

ben686@hotmail.com - Reply

For the following steps, please prepare:
  • For the following steps, please prepare:

  • P.I.N.D.A. probe (1x)

  • M3x10 screw (1x)

  • M3nS nut (1x)

  • The probe is a sensitive device, please handle it with care during the assembly!

  • The P.I.N.D.A. cable can be either black or grey, both probes are the same.

My sensor looks very different… it says “JIMOU Sensor, P/N: IB2T-B0802N-C4B.7/35/PUR”. Hope it works…

Mr Cookie - Reply

Hi Mr Cookie, it will be fine. This is our PINDA probe.

Jakub Dolezal -

My sensor doesn’t look anything like this one, it doesn’t have a label at all. I’m not entirely sure how far down to place the sensor.

Brian M - Reply

Start with the front print fan wire and place it under the cable clip. Gently push the P.I.N.D.A. probe through the mount. Create a loop on the probe wire, then place the wire under the cable clip.
  • Start with the front print fan wire and place it under the cable clip.

  • Gently push the P.I.N.D.A. probe through the mount.

  • Create a loop on the probe wire, then place the wire under the cable clip.

  • Slide the M3nS nut in the slot and tighten the probe SLIGHTLY with the M3x10 screw.

  • The exact position of the P.I.N.D.A. probe will be adjusted later (in Chapter 9, Preflight check), so there is no need to adjust the probe or tighten the screw fully at this point.

Ok here I almost screwed up and inserted the nut in the upper slot. Fortunately I realized in time and managed to take the nut out again. Maybe it’s worth mentioning this in the text? (Be careful to use the correct (lower) slot!). I know that there’s the picture but maybe a small reminder wouldn’t hurt.

Francesco Santini - Reply

I’m finding the PINDA probe exceedingly difficult to mount into the described hole… I’ve attempted several time and it appears the hole is either exactly the same size, or slightly smaller than the probe.

Thomas Hansen - Reply

I found wiggling it side to side helped, but also pushing from other side to help clean out hole, then moving back to correct side.

Rich -

Figured it out. The very thin bridging directly above the washer hole was preventing the “arm” which clamps down on the PINDA probe from moving upward. For me, removing that slight bridging solved my problem.

Thomas Hansen - Reply

THIS! I read this earlier and didn’t understand … now that I inserted the nut and retention screw, I understand - the probe is held in with “jaws” and the two thin bridges at the end of the jaw keeps the jaw from expanding. Without the bridges you could even pry the jaws open a little to help the probe go in.

Why are those bridges there….?

Rich -

I’m assuming we’re not supposed to remove that bridge, right? They clearly designed it to be there, as it would have printed just as well without it.

Evan -

I couldn’t insert my PINDA without removing these bridges!

Taylor Mills -

The ‘bridge’ is only a layer or two thick . I too didn’t understand it’s purpose (which is apparently none). I ended up screwing the sensor in and then breaking the ‘bridge’ so the M3x10 screw and nut could eventually do their job of securing the sensor (but it’s being screwed in seems to make the screw and nut somewhat redundant. I hope by screwing in the sensor I didn’t mess up the wire connections to same. The more one screws around trying to get things to work the greater the chance of bending the sensor prongs or creating other problems.

Gary Shumway -

I used the flat screwdriver as a wedge to open it up just enough to be able to slide the probe in quite easily.

Kevin Chua - Reply

This technique worked well for me, too.

Zachary Loafman -

This worked well for me also. I just pryed with the flat screwdriver ever so slightly in the top slot and wiggled the pinda and was able to get it.

Joe Banach -

Me too. The bottom “bridge” got stretched a bit by doing this, but I didn’t want nor have to remove them completely as suggested in another comment. Still, pretty sure removing the bridges is OK too, the probe feels tightly secured anyway.

Christophe Lermytte -

This worked for me too but both bridges broke. But there is no way this was going to fit with the bridges in place.

Jason Cumiskey -

so i use pliers to keep screwing it in. rotatiing in 45 degeeres at a time. is this how its supposed to be done? i mean there is a thread.

Brian - Reply

Hi Brian, inside the P.I.N.D.A. probe holder should be no thread, you can slightly widen (open) the holder and push the probe through, but be careful as you can break the printed part.

Jakub Dolezal -

I found it very difficult to more the probe to its position. It is hard to grab the probe because your fingers hit the cable clip. I ended up cleaning up the hole for the probe with a 8mm spiral drill (by hand).

Etienne van Ballegooijen - Reply

I found that I could rotate the probe and the threads on the probe would pull the probe through the hole. Be careful not to damage the cable when doing this. I found it easier to do this before routing the fan wire under the clip.

Jeff Heck - Reply

I to used my pliars to gently screw the PINDA into place.

Ray Benjamin - Reply

Also had problems setting the Linda probe. I pushed it I. From the other side in order to loosen it up and that seemed to do it. I like the idea of using the screw driver to widen it a tad when inserting. That would do it too I think.

Gene Dahilig - Reply

Well, certainly this is a pain in the….neck. My probe required some work to get it in. This method doesn’t seem too good for making fine adjustments once you get to the point of setting sensor height. I used a small screwdriver to slightly open the clamp. It maybe better to test and smooth as necessary, the inside of the clamp prior to getting to this point so it will be a known factor prior to PINDA installation. It seems to me that using nuts above and below the clamp would be better in the long run. Since the sensor is already threaded, this should be an easy modification for future updates.

George Miller - Reply

Stuck half way through, removed probe from holder. Found a small tag of plastic sticking out from joint between plastic cap and metal body. Cut it off and slide probe back in. Went in better, and along with gently prying with the screwdriver probe went fully in.

Brian hughes - Reply

Could use a recommendation from Prusa about whether to remove the plastic bridges. The instructions photos above show them attached and present, but after trying a few times it seems there's no way I can just gently push the probe through like the instructions say to. It seems to me like the bridges must be removed so I can pay the clamp open a bit.

343 Guilty Spark - Reply

First printer and first build so sorry if this is a simple question but would appreciate an answer to the bridge question also. I was able, with much trepidation, to get the probe through with the bridges intact but am concerned that adjusting the pinda on any fine scale later will be impractical. Should/can the bridges be removed? I saw on the Sanladerer build video (3:14:42) that the bridge wasn’t present at all but its an older build and many of the parts/steps are different. Thanks.

George Carson - Reply

Hi George, the “bridge” is there to prevent you from opening the PINDA holder over certain limit, which will result in breaking the holder. Proceed carefully while inserting or moving with PINDA probe and you can remove the “bridge”. However, you should be able to move the probe even with the “bridge” in place.

Jakub Dolezal -

Place the Extruder on the Y-carriage as in the first picture. Ensure the correct orientation of the printer, shorter extrusions must be facing towards you. If needed, lower the X-axis so you can see the entire X-carriage. It is needed for the next step. Take the cables from P.I.N.D.A. probe and front print fan, slide it between the lower smooth rod and belt.
  • Place the Extruder on the Y-carriage as in the first picture. Ensure the correct orientation of the printer, shorter extrusions must be facing towards you.

  • If needed, lower the X-axis so you can see the entire X-carriage. It is needed for the next step.

  • Take the cables from P.I.N.D.A. probe and front print fan, slide it between the lower smooth rod and belt.

  • Take the cables from Extruder motor and left hotend fan, slide it between the lower smooth rod and belt.

  • IT IS VERY IMPORTANT to place the cables as shown in the pictures. Please double check your steps.

  • Cables from hotend will be placed under the lowest smooth rod. We will arrange them later.

First I had the printer the wrong way around (front facing me instead of back) and put the cables in from wrong side and had the extruder the wrong way. Would be helpful to add a note in the beginning to check that you have the printer oriented he same way as in he picture (back facing yourself).

Kari Söderholm - Reply

Thanks Kari. Almost did the same thing..

Øyvind Taknæs -

Thank you both for the feedback, description updated ;)

Jakub Dolezal -

Unless I missed a step, need to add how to lower the Y axis to match the picture, assuming rotate both axis until down ‘far enough’ being careful not to go out of level? (I used a ruler to make sure the sides were more or less level)

timcdoc - Reply

Hi, I updated the description of this step ;)

Jakub Dolezal -

Yeah, please add that you need to lower the Z axis down to get the the screws in the next step in, I don’t believe I missed a step about this…

blueyes13@gmail.com - Reply

Step description updated ;)

Jakub Dolezal -

Could do with a larger image on the printed manual. Too small to see cable routing.

Brian Knight - Reply

For the following step, please prepare: M3x40 screw (1x) M3x30 screw (1x)
  • For the following step, please prepare:

  • M3x40 screw (1x)

  • M3x30 screw (1x)

  • M3x18 screw (1x)

  • Place the Extruder near the X-carriage and check no wire is pinched. There is a slot in the X-carriage for the motor wires, see the picture. Bend the motor cable in it and leave the fan wires straight.

  • Mount the Extruder on the X-carriage using the screws above. Tighten all screws, but not fully. We need to arrange the cables again, this time in the back.

  • Guide the cables through slots (channels) on both sides of the Extruder. On the left side, it is Front Print fan and P.I.N.D.A. probe, on the right side Extruder motor and Left Hotend fan.

  • Ensure again the cables are in the channels and not pinched between printed parts. Now, tighten all screws, equally to prevent issues.

First guide the cables (especially from the extruder), then tighten the screws.

Michal - Reply

Make sure the stepper and hot end fan wires are in the side channel otherwise they will get pinched and damaged when tightening the three screws.

William Dutcher - Reply

+1 William, I had to take mine off and reroute the cable because I missed that.

Austin Hampton - Reply

Guys, thank you for the feedback. Description of the step adjusted.

Jakub Dolezal - Reply

The M3x18 head sunk in far deeper in the part without any added resistance where it should have stopped. A print quality issue?

Bo Gustafsson - Reply

Hi Bo, the M3x18 screw will be fixed by M3nS nut inserted earlier. No resistance along the path (hole) is needed.

Jakub Dolezal -

Jakob, please emphasize placing the extruder stepper motor wires in the channel above the beige fan. I still missed that.

RWReese - Reply

Hi, there is an extra picture for this in step 21. At this step it is too late as the fan is already mounted, if we are talking about the channel above the fan.

Jakub Dolezal -

Agreeing with all the above comments!

My suggestion:

Mount the Extruder on the X-carriage using the screws above. Take especially care that the cables from Extruder and hotend fan are guided in the slot/channel.

Tighten all screws, but not fully. We need to arrange the cables first.

Tom Ludensen Christensen - Reply

Hi Tom,

thanks I will stress out, which cables must be arranged.

Jakub Dolezal -

Additional information needs to be provided for routing the extruder stepper motor cables.  I tucked the cables into the channel above the fan but didn't realize that there was another channel on the x-carriage assembly that the cables needed to be routed through.  I ran the motor cables through the top channel, then around the side of the fan, and into the slot pictured above with the orange arrows.

Corey Dryja - Reply

Corey, had the same cable routing problem as you and I agree there needs to be better instructions.

Thanks

Ezra hawkins -

I definitely agree, the second channel in the x-carriage assembly is on the back side because of the orientation of the printer so many people like you and me have and will miss it. A picture that shows that part of the x-carriage assembly must be addded.

Levent Alpsal -

Hi guys, this step will be expanded to cover the process step-by-step. However, there are some limits, I need to reorganize the steps.

Jakub Dolezal -

thanks Corey, I completely missed that second channel.

There definitely needs to be a picture and some instructions clarifying the guiding of the motor cables!

Adam White - Reply

Really happy that you learned from my folly and didn’t make the same mistake that I did.  This suggestion really needs to be added to the guide because others have been posting pictures of their build with the same cable routing mistake I made.  People are going to start cutting their cables in half.

Corey Dryja -

Yeah, a second picture is absolutely necessary to do it correctly.

Mr Cookie - Reply

Yup and I’ve been seeing people post pictures of their builds with their extruder motor stepper cables routed properly.  This really needs to be added to the guide.

Corey Dryja -

Guys, thanks for the feedback. It is on my to-do list.

Jakub Dolezal -

Don’t forget to place the cables in the channels before you start to screw. This is very important, you can even destroy your cables, if it is not placed properly before placing the screws.

Miroslav Piencak - Reply

Might want to emphasize earlier the location of the extruder fan wire out the back. I guessed (wrong) from the pictures. Maybe a picture of the fan wire in the step where the fan is mounted would be nice.

Joe Pighetti - Reply

I saw the side channel for theextruder motor and fan wires on the mount, but didn’t realise that channel leads to a larger opening on the back of the mount. The wires need to go in there, then through the side channel. That way they don’t get pinched between fan and mount.

Bas - Reply

I did it wrong the first time, too. Perhaps something like, “Note that there is a vertical channel on the X-carriage - ensure that the extruder and fan wires are positioned in this channel and then routed back along the horizontal channel before tightening screws.” (And a front or side view picture would help to clarify that.)

Bill Magley - Reply

This is probably the most confusing step if you don’t realize that there is a cutout and path for the stepper motor cable. This is something I spent a while with on my MK2S build and luckily remembered here. Maybe add a picture of the pocket in the X-carriage so builders get the idea. I suggest adding more detail. What worked for me was to hang the assembly from the 40mm screw, attached loosely. Then route the cables into the slots. Maybe add a warning that if the extruder won’t easily seat against the X-carriage, stop and readjust the cables. When you have it right, it comes together perfectly. When you don’t the temptation is to start to force things and that always ends badly. As with everything else PR does, it’s well engineered but not easy to explain sometimes.

Ira Schonfeld - Reply

Almost broken my cables, since I did not realized how to route the extruder cable from the first channel to this one…

Lyubomir - Reply

If you can‘t reach the top m3x40 hole you need to lower the X gantry.

Per Hansen - Reply

Lowering should have been a much earlier step, as if it’s too high you’re already balancing the assembly in one hand.

Evan -

Thanks, I was totally confused here. Simple, once you point it out.

Shelley Dorbin -

Cable placement should go first on the list. I almost messed things up too. The M3x18 screw can go way too deep, it should be mentioned not to do that.

Zsolt van den Mar - Reply

Guys,

thank you for the feedback, step will be updated.

(@mirecxp, @pighetti, @bas, @bmags, @irasch, @lpetrov, @vandenmar)

Jakub Dolezal - Reply

ARGH - could you use something other than two colors that look like eachother? Symbols or something would be helpful for those of us who are color challenged …

Peter Larsen - Reply

Is the one circled in Green really supposed to be M3x30? Mine sticks out too far. The M3x18 seems to fit here. It could be that the nut on the other side got turned a bit and is the reason I can’t fit the M3x30 in there, but I want to verify before I have to pull the whole thing apart…

Brien King - Reply

Hi Brien, yes it should be M3x30, make sure there is no obstacle in the hole. Use for example and Allen key.

Jakub Dolezal -

I would suggest making sure all the screws thread nicely before mounting on the X-Axis. I had to take mine off and remount it after the M18 wouldn’t catch.

Shaun Collins - Reply

Unfortunately I had to glue back one of the tabs on the left side of X carriage, where the motor wires go. It came off earlier in the X carriage/belt assembly. Maybe if you Strengthen the walls of the printed pieces a bit it might help.

Erin Baker - Reply

The lower wing on the right hand side (for the nozzle fan) said “crack”. Let’s pray this wing is not crucial …

Mario Witdoek - Reply

My M3x30 screw (the green one) isn’t catching on anything. Did I miss a nut somewhere?

Brenda Bell - Reply

Hi Brenda, have a look at step 6 5. E-axis assembly

Jakub Dolezal -

Just thought I would share. I had a struggle getting the m3x30 to thread in properly. It is still not fully threaded in (1/4) of head exposed on surface. Tried removing the bolt and it is stuck in the extruder assembly. After the 1st attempt I tried using an Allen key to make sure holes were properly aligned and there were no obstacles. It is possible I pushed material in the hole on the 1st attempt. I also saved the m3x30 to tighten last to ensure all 3 holes were as close to aligned as possible. Everything seems to be secured tightly as is :). Maybe add a step where you hand thread the bolts through the holes on the extruder side before mounting to the carriage? It’s been a great build so far!This has been my only real issue thus far. May have ruined the filament sensor in my haste trying to remove the bolt. But all pins are bent back straight, sensor is secure again and solder remains intact. Take care :-)

Cameron Freitas - Reply

Update: I believe the nut is slipping inside the hex hole where you press the nut in. I'm going to try a small pair of needle nose pliers to pin the nut down as I try to screw the m3×30 bolt in from the carriage side and see if I can get the bolt to thread on the nut the rest of the way

Cameron Freitas - Reply

Also had problem with the 30mm nut sticking out from the surface. In step 16 you install two M3nS nuts; in this step the 30mm screw goes into both of them. Turns out that the further back M3nS nut had gotten push too far in so its threads no longer lined up with the screw hole. It is fully wedged - I can’t get it out. As Brien noted the 18mm nut works. It’s only engaged with the first nut. I’m hoping this will be strong enough.

Brian hughes - Reply

Like a couple of others, I had one of the thin tabs on the x carriage crack almost completely off as well. It was the one on the right side, where the extruder motor wires route through. I’m not sure exactly when this happened, but I just noticed it, and I am attempting to repair it with super glue. I suspect that this was a result of the tab being fragile and colliding with lower x carriage bearing, which is not secured to the x carriage. I think if the carriage had been attached to the bearing with a zip tie like the top section, this would not have happened.

Jeff Webb - Reply

I discovered that I pinched the motor cables a couple of steps later. I read the warning but I didn’t realize there are cable channels on both parts until later. Hopefully, I didn’t break them. Since pinching the cables can destroy them, one of those big red phases would be good here: “IT IS VERY IMPORTANT to route the cables in their channels on BOTH parts to make sure the cables will not pinched and damaged.”

Lee Clark - Reply

Locate the cable for filament sensor in the package. There are two types of the connectors on the cable:
  • Locate the cable for filament sensor in the package.

  • There are two types of the connectors on the cable:

  • The 4-pin connector for the sensor (used now)

  • The 5-pin connector for the EINSY board (used later)

Are these backwards? Einsy board can’t accept a 5 pin plug?

Cameron Lamont - Reply

Hi Cameron, 4 pin connector (marked green) goes to the sensor and the 5 pin connector (marked orange) goes to EINSY. In case you can't fit it, you must be using different port on the EINSY board.

Jakub Dolezal -

I had the same problem. Since the picture doesn’t label the lines (that comes in step 32) you think the PINDA probe is where the filament sensor goes. I just took it all apart - and realize that the picture isn’t a good guide on section 8. Suggest starting with a complete map of all plugs and some help identifying the cables.

Peter Larsen - Reply

Use the cable from the previous step and connect it carefully to the filament sensor. Note the connector has two different sides. The side with safety pin must be on the left (white wire is facing up and red down). Gently rotate the cable (clockwise) to create a small loop, see the second picture.
  • Use the cable from the previous step and connect it carefully to the filament sensor.

  • Note the connector has two different sides. The side with safety pin must be on the left (white wire is facing up and red down).

  • Gently rotate the cable (clockwise) to create a small loop, see the second picture.

  • Push the cable through the opening on the X-carriage.

rotate the cable to the loop because a straight wire directly ouf of the plug will collide with the frame or spool holder on top when reaching 180mm or more.

maybe, if you’r using a custom spool holder, the spool holder itself won’t work any longer on a MK3

Heiko Schultz - Reply

Good point, this should be added to the step to explain why you need to loop the cable as people might not bother.

Robert Hunt -

As silly as this sounds, now is the perfect time to notate that the bottom bearing needs to be properly seated, mine was loose to the right of the extruder mount at this point as it was not attached in any way (so still on the rod, not seated in the printed mount) and I didn’t catch it until self=test calibration on the X-Axis failed as the bearing was impeding travel…. it was a major pain to go back and fix it.

Benjamin Curto - Reply

Is it normal that my filament sensor wiggles a bit in place?

Andreas Sjolund - Reply

Hi Andreas, it is not ok. The sensor must be secured in place. Please see Step 8.

Jakub Dolezal -

I think that you should reiterate in the instructions that it shouldn’t be wiggling at this point, or maybe reiterate much further back to recheck so we don’t have to disassemble so much.

Erin Baker -

I think I found an easy solution if someone else comes across this problem. Unmount the extruder. You don’t have to disassemble anything else! Take the long side of your allen wrench get it sideways into that screw hole that is mounting the sensor and you should be able to screw it in more securely.

Erin Baker -

Be careful that your “small loop” is not too big vertically! Despite the fact that I attempted to check to make sure the wire did not interfere with the horizontal travel on the X axis, the loop I made was a little taller than the connector, and a little wider than the bearing. This made it collide with the spool holder, which of course one doesn’t install and thus find out until the VERY LAST STEP OF THE ENTIRE BUILD! Be sure to look at the third picture of this step and make sure your final loop is “tight enough”. It should not extend beyond the back of the rod bearing, nor should it go higher than top of the connector.

Joel Kozikowski - Reply

Hi Joel, thanks for sharing your experience with the build. The loop should be really small as in the picture. Just few mm.

Jakub Dolezal -

Does the “safety pin” actually click into place to lock it in? I was expecting it to do that, but even with a good amount of pressure it doesn’t click for me. It seems stable and doesn’t look like it will come loose, but it worries me.

Bill Magley - Reply

Nope……………… .

John Hawkins -

… and it was at this point when I discovered the filament sensor was loose :-(

It seemed secure waaaay back in step 8 ¯\_(ツ)_/¯

Remove the extruder (3 screws). Remove idler door (3 screws and 2 translucent washers), tighten sensor screw, replace idler door (don’t forget the 2x translucent washers), and back to step 25.

Andrew E. Mileski - Reply

Erin Baker you are a life saver!!! Mine was just a little lose but I was able to angle the long end of the allen wrench in there and tighten it! Phew!

Jeffrey Gillespie - Reply

Also had a problem with the sensor being loose, Erin Baker’s solution worked perfectly!

Ben - Reply

Starting mid of February 2018, there will be only one 50cm NYLON filament included. There are two NYLON filaments included in the kit with lengths 50 and 30 cm. Both have Ø 3 mm. For this step please use the longer one and DON'T TRIM any of them! Using the pliers cut one end of the filament to create a tip.
  • Starting mid of February 2018, there will be only one 50cm NYLON filament included.

  • There are two NYLON filaments included in the kit with lengths 50 and 30 cm. Both have Ø 3 mm. For this step please use the longer one and DON'T TRIM any of them!

  • Using the pliers cut one end of the filament to create a tip.

  • Check the tip is similar to the third picture.

its is better to cut out with a cutter

printminion - Reply

We are using the tools, which are included in the kit, but if you have some more appropriate tool at your disposal, use it ;)

Jakub Dolezal -

The included pliers/cutter just squished the filament without breaking it. I had to use a different tool.

Neal Tibrewala - Reply

Hi Neal, it is possible to do it with included pliers (picture above is the proof), in case you have a better tool, please use it :)

Jakub Dolezal -

use nail clippers

PaulHarris -

You should write the line with “Starting mid of February 2018, there will be only one 50cm NYLON filament included.” on the top. I searched all my boxes twice because i searched for the second nylon filament mentioned in the first sentence :(

Sebastian Moder - Reply

Agreed. Just added 15 minutes to the build time and 100 swear words to my tab.

Jeremy -

I spent a good 15 minutes looking around for the “second” nylon filament. Absolutely agree

Woger Dog -

Mine did not ship with ANY nylon fillament

Eric Harten - Reply

Same with me - no nylon filament in the package. Is it OK to just go ahead without it?

Mark Chu-Carroll -

Guys (@hartene, @markcc), please check the package once more, the nylon filament could be stuck at the bottom of the box. If you can’t find it, please contact our support at info@prusa3d.com

Jakub Dolezal -

It would be easier to understand this step if the purpose of the filament is explained, that its purpose is to support the cables and not to be used for printing. I used the printed guide, hard to understand this step, why insert filament between the cables? Very hard to se the hole, with the X-carriage back mounted according to the printed guide.

Hans Palm - Reply

Very agreed!

Huebners -

DO NOT TRIM! It's critical that you preserve the length of the Nylon strip.

Make sure you make a nice, clean tip.

For lack of a better analogy, it’s more of a circumcision, than anything else. Please consult a Mohel.

Bleak Disclosure - Reply

Better still than write the line with “Starting mid of February 2018, there will be only one 50cm NYLON filament included.” on the top

rather amend to say There is a single NYLON filament included in the kit with Ø 3 mm and length of 50 cm. DON'T TRIM it!

PaulHarris - Reply

I must be lucky - I have a single piece about 50cm long of black filament - but mine measures 3.25mm diameter !!!

No amount of pushing or twisting is going to get that through a hole which is 3mm diameter AFTER clearing out all the stringy bits!! Grrrrrrrr!

Mark Baker - Reply

So, the reason I consider myself lucky is because I have an old 1/8” tapered reamer Ha Ha, now it is a PERFECT FIT!

Mark Baker - Reply

Locate the hole for the NYLON filament. Using the smallest Allen key ensure there are no obstacles inside. Using the pliers insert the NYLON filament in the slot. Hold the extruder with your second hand. BE EXTREMELY CAREFUL as the pliers tends to slide and you can easily damage the wires!!!
  • Locate the hole for the NYLON filament. Using the smallest Allen key ensure there are no obstacles inside.

  • Using the pliers insert the NYLON filament in the slot. Hold the extruder with your second hand.

  • BE EXTREMELY CAREFUL as the pliers tends to slide and you can easily damage the wires!!!

  • To check if the filament is seated properly, gently pull it with your hand. The X-axis should bend a little, but the filament must remain in the slot.

  • If you have issues, try to adjust the tip on the filament.

It would be helpful if we knew what kind of connection is happening inside … so we know how to adjust the tip.

Rich - Reply

Hi Rich, the connection type is mostly friction. The tip on the filament is used to enter the hole easily.

Jakub Dolezal -

Please explain why this nylon filament is only visible on step 30 ?

I can’t see it anymore on steps 36 &37 pictures.

Even on video build found on YouTube, this step seems missing.

What the utility of this piece ?

Stephan - Reply

Hi Stephan, the nylon is not visible just because it is hidden under other cables from the Extruder, but it is still there. Nylon is much stiffer (rigid) compared to the other cables, it will hold the entire bundle up during prints and also retakes most of the load introduced by the moving Extruder.

Jakub Dolezal -

I’m unable to insert the 50cm NYLON filament into this slot.  I cut the NYLON at an angle as requested in the previous step, though when I try to push it through the slot, the pliers end up scratching the NYLON instead of being inserted.  I tried to cut the NYLON angle another time, with the same results.  Is the NYLON supposed to go all the way through and come out the left side, as the picture shows?

Richard January - Reply

I think the nylon just dead-ends into a friction lock inside the hole - the black cable/string on the left is the PINDA

343 Guilty Spark -

“insert the NYLON filament in the slot” - about how far? Like Richard above, I find it very difficult to insert, even with a perfect tip cut.

Gerry P - Reply

Hi Richard and Gerry (@rjanuary, @gerrypez),

in case you can't insert the nylon filament in, please try decreasing the diameter of the nylon using a knife (make the tip slimmer). You should insert the filament few millimetres in, no exact value is given, but I will discuss this with the devs.

Jakub Dolezal - Reply

Could an approximate length of filament that will be pushed into the extruder assembly be documented? I was only able to get about 1cm to go in (with laborous pushing & twisting) and I don’t know if that is sufficient to support the wiring bundle over time.

Jeremy - Reply

For me, this was definitely the most frustrating part of the entire build. As I look at it, it seems to me that the insertion of the nylon is really just to have it be held in place while you get the rest of the cabling under control coming out the back of the extruder assembly. Once past Step 39 the zip ties will assist with keeping the nylon in place. So yes, only a couple millimetres of insertion is enough here.

But, that is a tough couple of millimetres!

My suggestion would be to adjust the hole to be a wider diameter with a hook ridge around the circumference 10mm into the hole. Then with a notch on the end of nylon it would simply slide in and lock into place, holding it there while the rest is done.

SteveP - Reply

I twist the nylon filament in by hand instead of push it in. Way easy and secure too.

W Lai - Reply

Twisting the nylon worked easily for me as well.

James Shumpert -

Oh wow! Simply pushing it in there was not working. Twisting in there with the pliers worked wonders. This part should be changed because screwing the nylon in there like a screw with the pliers is the only way to do this step.

Brandon -

God bless you the twisting worked so easily.

Edward Chavez -

TWIST IT IN WITH THE PLIERS. THANK W Lai.

Edward Chavez -

Small vice grips are your friend on this step. Tried it with the supplied tools but that was going nowhere.

Trevor Friesen - Reply

I cleaned out the hole for the filament by manually rotating a 3mm drill bit into it. That worked.

Etienne van Ballegooijen - Reply

make a L bracket screw into hole and then have nylon attach to that

vincent bartlett - Reply

I whittled the tube for a few mm in order to reduce the diameter, and then used vice grips to hold it. That worked pretty well.

marhar@gmail.com - Reply

How deep is the hole we are inserting the filament into?

tim - Reply

3 mm Nylon does not go into the hole. Just bends. Rotation didn’t work. Very frustrating. Was liking the build until the last hour. Working on assembling the wires and the 3 mm nylon fell out.

Kurt M. Sanger - Reply

Found the problem. 3.4 mm Nylon does not fit in a 2.4 mm hole. Skipped this step.

Kurt M. Sanger - Reply

The hole is a full mm smaller than the supplied nylon? Wtf?

Christian B. Nielsen - Reply

Hi Christian, this is why the tip is created before, you need the nylon to hold in the hole, so the diameter can't be the same. However, one 1 mm difference is too big. Are you able to place the nylon in?

Jakub Dolezal -

No, I can only get the tip in, an only about midway up the diagonal cut I made. I'm gonna have to hope the zipties are enough to keep everything in place.

Christian B. Nielsen -

With some random Dremel tools, I sharpened the nylon in a more conical way, to increase the grip/friction. It seems OK now, but I’m not going to pull it to test :)

Christophe Lermytte - Reply

I had a 3.25mm thick nylon piece and it did not fit in the hole. I found that using a 3.0mm drill to make the hole bigger worked okay.

Olivia Williams - Reply

The hole is too small (as stated above) to properly insert the nylon filament. For those that do not have metric drill bits, the 7/64” (2,78 mm) drill bit can open the hole sufficiently to force fit the filament. Use your fingers to twist the drill bit, just to make sure you don’t over do it.

David Jerrell - Reply

Even though I have metric drill bits, I was worried about drilling into the extruder assembly. Instead, I used a hobby knife to carefully thin the first 4-5mm of the nylon filament’s tip. Then I used a set of locking needle-nosed pliers to grip the nylon along the axis of the filament and twisted it into the hole like a screw. Because the pliers locked down, they didn’t slide on the nylon and I could switch my grip to get 2-3 revolutions.

Federico Hatoum - Reply

Another comment for this, you may want to state that the filament is for the wire bundle guide, to ensure that it clears/stays out of the way during operations.

David Jerrell - Reply

Amen. At first I thought this step was for calibration or gear testing and important. It’s kind of comical to learn that all this futility for inserting the nylon is just to hold some wires lol.

Mike Krall -

After trying all the above tricks with no luck, I put the filament in the freezer for about 5 minutes. I was then able to “screw” it in using pliers with not too much force. The cold filament could be a little brittle so be careful. .

Daniel Smith - Reply

David Jerrell’s suggestion worked well for me: I used a pin vise and a 7/64” drill bit to open up the hole, then a twisting motion with the nylon. It’s snug now.

Craig Niederberger - Reply

This step should be done during STEP 3.12 before attaching the (x-carriage: Assembly) so that the the part can sit flat to give more leverage without trying to hold the whole extruder assembly including to prevent any parts from breaking or bending. The filament would not get in the way of any other assembly from there on and provide maximum leverage to push the filament in.

Kris Sovers - Reply

I too used a 7/64” bit to clean the hole out. It was still tight enough that I had to screw the filament in, but it was finally possible to get it in there.

Harold Toler - Reply

Had to use the 7/64” bit *and* a file on the filament.

Brenda Bell - Reply

Doh! We inserted the nylon into the wrong hole. They nylon must go into the hole very close to the lower single linear bearing, beneath both levels of belt. Somehow we put it in the hole with a nut listening inside, above, which later is needed for screwing the back plate on (step 35-38), with the result that the back plate couldn’t possibly close up on the extruder (the nylon would have needed an impossible path).

Jonathan Histed - Reply

I also initially used the wrong hole. Perhaps adding a red circle with a slash (no as in do not enter or no left turn) over the wrong hole would help assemblers see that there are two holes and one is wrong..

Paul Post - Reply

The filament is curved, not straight.

Any guidance on what orientation to insert it on?

Andrew E. Mileski - Reply

After slightly thinning the pointy bit, and very lightly cleaning-up the hole entrance with a hand-spun 2.9 mm drill bit, the 3.0 mm filament seated firmly using pliers. It went in with two very noticeable “steps".

No way it is coming out now!

Filament is bowed downward (there was no orientation guidance given).

Andrew E. Mileski - Reply

I received my kit on 6/20/2018. On my assembly, this filament went in just like the pictures show. As they explained, they use the pliers (included with the kit) to cut the end and install the filament into the hole. What I did was to measure the depth of the hole and transfer that to the filament, marking it with the edge of blue painters tape. Using the pliers, I easily slipped the filament into the hole until it was completely inserted up to the edge of the blue tape. A quick pull on the filament assured me that the filament was secure.

George Miller - Reply

I cut the notch into the filament then using the pliers blunt section clamped down on the notch, this seems to centre it to more of a point centrally. After this I used the pliers to twist it in and had it tight in place within a minute. Hope that helps anyone

Nicholas Klein - Reply

I found a tapered screw in my extra screw bin that had a shank slightly smaller than the hole and threads slightly larger than the hole. I screwed that into the hole, then removed it, and twisted the nylon into the hole. It worked fine and holds on tight.

TK_bit_twiddler - Reply

This was one of the most frustrating parts of this entire process. There’s just no way to make this work unless you own extra tools / drill bits / etc..

Nicholas Nothom - Reply

I tried freezing, trimming and twisting to no avail. Finally just drilled a little bit to make hole slightly bigger and nylon goes and stays in, didnt even have to cut a point. So once again poor QA as many of us have seen through these steps, just make the hole slightly bigger.

mjb - Reply

impossible to push the nylon cable through… my nylon cable makes 3.3mm of diam.

jorgemarmo - Reply

This is by far the most frustrating part of the build so far. I've spent over half an hour trying to get the filament in. I ended up having to trim the diameter of the filament with a knife, sand it down with sandpaper, and finally use a vise grip to jam it in. Terribly designed.

hunnaabraham@gmail.com - Reply

Not even close to fitting on my kit received a few days ago.

Chris Combs - Reply

On the MK2S kit, the instructions specify that the filament (which, as others have mentioned, has a pronounced curve to it) is meant to be oriented into the slot so that the filament’s natural bend, moves upward, so that it opposes gravity as it supports all of the other cabling (i.e the c shape of the filament should be oriented so that the opposite end, the end not going in the hole, curves over the top of the printer). I repeated this same scheme while assembling the MK3 but I believe that this needs to be clarified for new builders (if, indeed, it is important here).

MagicDM - Reply

I’ll also add, for builders struggling to get the filament to fit, that the key really is to cut a long, sloping point at the insertion end (you really should use clippers for this if you have them, rather than the supplied pliers - I believe that the pliers are not really the ideal tool for the job - understanding, of course, that the Prusa team probably challenged themselves to find a way to do the entire assembly with only the supplied tools). If you have clippers, you want to angle as long of a diagonal cut (about 30 - 35 degrees) across the width of the filament as you can (this technique will also come in handy, later, when you insert filament into the extruder for actual printing).

MagicDM - Reply

For the following steps, please prepare:
  • For the following steps, please prepare:

  • X-carriage-back (1x)

  • Cable-holder (1x)

  • M3n nut (1x)

  • M3x10 screw (1x)

  • The M3x10 screw will be used temporarily, use one from the spare bag.

  • M3x40 screw (1x)

Add Comment

Insert the M3x10 screw in the X-carriage-back. Tighten it completely. Rotate the printed part and insert the M3n nut. Tighten the M3x10 screw until the nut slides in the printed part. Note the shape of the cutout for the nut, you might need to adjust (rotate) the nut.
  • Insert the M3x10 screw in the X-carriage-back. Tighten it completely.

  • Rotate the printed part and insert the M3n nut.

  • Tighten the M3x10 screw until the nut slides in the printed part. Note the shape of the cutout for the nut, you might need to adjust (rotate) the nut.

  • Remove the M3x10 screw and place it back in the spare bag.

Stuck here. Nuts keep falling off. Cannot sit tightly on printed part

Cell99@Mike - Reply

Doesn’t really matter, just move onto the next few steps where the cable-holder is attached, it will keep the nut in place.

Robert Hunt - Reply

The bag of spare fasteners was a good idea. At this step the nut seized on the M3x10 screw before the nut bottomed. It was impossible to get a good grip of the nut since it had sunk enough in the plastic to make it ungrippable. The head of the screw had to be drilled off so the nut could be removed. Luckily the new nut went in well and did not seem to spin in the now by the seized nut reamed hole.

Bo Gustafsson - Reply

Managed to get the nut to sit. I used a plier to twist the nuts as far in as possible and then I screw the m3 screw from the other side to pull the nut in. If the nut is dotted properly the next 2 step is easier.

Cell99@Mike - Reply

I had the same problem Bo encountered. I believe this step should be removed as the nut will be retained during, what is currently, step 30. I will also have to cut the bolt head off and I have not determine if I will need to reprint the part yet. Maybe in the future these components should be reviewed to relocate the retainer nut so that it is not so close to the bottom x bearing housing. I may reprint this piece with the wire harness bolt moved down 1-2mm.

Regards,

Jeff Underly - Reply

On my X-carriage-back (version A9) the “MK3 sign” was very shallow, almost invisible. After tightening the M3x10 screw and successfully pulling the M3n nut into its hex-shaped hole I was concerned the nut protruded too far and would be in the way of the bottom x bearing. I removed the M3x10 screw and did a quick test fit of the X-carriage-back against the bearing. The nut was definitely protruding about 1.5 mm too far! Using the M3x10 screw I fixed this by repeatedly and carefully tightening and loosening the screw to gradually pull the M3n nut farther into its hole until the nut was flush with the plastic. Warning: a protruding nut could damage the bottom x bearing when the X-carriage-back is mounted in Step 35.

Bill Waring - Reply

Prepare the M3x40 screw and cable-holder from the previous step. Tighten the screw all the way through the printed part.
  • Prepare the M3x40 screw and cable-holder from the previous step.

  • Tighten the screw all the way through the printed part.

  • Note there is a recess (slot) for the screw's head on one side of the printed part.

You can not tighten it yet. It just slides in.

Michael Stegen - Reply

Hi Michael, you should be able to slide/push the screw through the part, but sometimes Allen key is needed.

Jakub Dolezal -

There are a number of places in this manual where the word “tighten” or “tighten completely” may not be the best choice of words. In this case, “fully insert” would be better. Likewise, in Step 28 “tighten completely” is not possible as there are no threads to allow the screw to become tight. Perhaps “thread the screw completely through…” is better. On the Y axis belt assembly, I cracked my belt holder following the instructions to “tighten completely” and put a little too much force not yet having a feel for how brittle the plastic is. I think Michael is just pointing out that the language could use some improvement on this step (and maybe others).

Ryan Sealy - Reply

It would be more correct to say recess instead of slot in “Note there is a slot for the screw's head on one side of the printed part.”

Aaron Pool - Reply

Hi Aaron, thanks for the suggestion, description updated.

Jakub Dolezal -

Place the X-carriage-back as in the picture. You must see the MK3 sign. Tighten the X-carriage-back and the cable-holder together. Check the "u-shaped" slot is aligned properly on both parts.
  • Place the X-carriage-back as in the picture. You must see the MK3 sign.

  • Tighten the X-carriage-back and the cable-holder together.

  • Check the "u-shaped" slot is aligned properly on both parts.

Printed part is 3mm too long. The m3x40 screw needs 6mm to secure to the trapped nut, and it only has 3mm overhang once fully inserted into the cable holder.

Bill Connelly - Reply

Hi Billy, are you sure the screw was fully inserted and nothing was blocking it?

Jakub Dolezal -

Same problem with mine. Could hardly grab the threads of the nut.

Tim -

Your part must have had better printing, there’s no discernible MK3 marking on mine

Steve Worcester - Reply

Hi Steve, the parts were taken from our printing farm. It might be different part revision.

Jakub Dolezal -

I shoved the nut in twice, both times screwing it in. Then rescrewed the long screw, and it didn’t go through properly. I think the screw needs to be longer, or like Bill said, the part is too long/not deep enough for the screw.

Mr Cookie - Reply

Hi Mr Cookie,

did you follow the instructions in Step 28? If the nut isn't deep enough you won't be able to reach it with the screw.

Jakub Dolezal -

I had top go back and redo step 28. I’d been too gentle for fear of breaking something. Once the nut was properly sunken in I was able to get the screw in place.

H4irBear - Reply

thanks dude! helped in my case

Artem -

The “MK3” isn’t legible on mine, either - using a flashlight to light it from an oblique angle, I can see what looks like it *might* say MK3, but I couldn’t see it under ordinary room light. Maybe just say, “Smooth side up”?

Bill Magley - Reply

No Mk3 on mine

Jonathan Butters - Reply

Yup, looks like the latest revision does not have the “MK3” marking.

Evan -

As of May 3rd 2018 set of pieces, there’s MK3 marking on it:

https://i.imgur.com/RGaoe0d.png

Alex Tutusaus - Reply

Anyhow, I had the same issue as OP and I opted to sand the black piece a few um in order for the screw to grab the back exrtuder part better.

Alex Tutusaus - Reply

Same issue with the M3x40 not having enough length to make a secure connection with the M3n in the X-carriage-back.

Zaki Ullah - Reply

Push the cables from the Extruder THROUGH the X-carriage-back. Start with Extruder motor and the Left hotend fan. In the next step add the Front print fan and P.I.N.D.A. probe cables. Cables from hotend and filament sensor are NOT GOING through the X-carriage-back!
  • Push the cables from the Extruder THROUGH the X-carriage-back. Start with Extruder motor and the Left hotend fan.

  • In the next step add the Front print fan and P.I.N.D.A. probe cables.

  • Cables from hotend and filament sensor are NOT GOING through the X-carriage-back!

  • Carefully insert the nylon filament and then slide the X-carriage-back towards the X-axis.

Check to make sure the nylon fits now before putting the cover on. My hole was too small.

Paul Betz - Reply

I had to go back to this step to add the nylon! I can highly recommend doing it NOW! Much less chance to damage the wires!

Christoph Stahl - Reply

Agreed - place filament now and be patient and careful while tightening in step 35.

David Beach -

I agree that the nylon needs to be inserted now. I had to undo everything from step 38 back to this one to get the nylon in.

Ken Ondo - Reply

Guys (@stahlfabrik, @kjondo), the decision to put the NYLON filament later on is based on our experience during internal tests. Many users managed to pull the NYLON filament out during the X-carriage-back assembly, but thanks for the feedback. We will consider some changes.

Jakub Dolezal - Reply

my printed manual had several steps in between this and the last one, about the cable and where (and how) to plug it in. They seem to be missing online, would have been useful for knowing if it was plugged in the right way

David Kaufmann - Reply

Hi David, there was an updated to this chapter, which included different steps arrangement. Nothing is missing, which cable do you have in mind?

Jakub Dolezal -

It seems like nylon needs to go through its own hole separated from the rest of the cables. Is this correct?

Gaston Dombiak - Reply

Never mind. Nylon was incorrectly inserted in step 30. Fixed that

Gaston Dombiak -

Lol, same it came out with thread markings. I didn't even see that till this step.

Edward Chavez -

Before pressing the X-carriage-back against the X-axis, place the filament sensor cable through the slot. See both pictures. Check the cables are not pinched between the X-carriage-back and the X-axis!!!
  • Before pressing the X-carriage-back against the X-axis, place the filament sensor cable through the slot. See both pictures.

  • Check the cables are not pinched between the X-carriage-back and the X-axis!!!

Add Comment

Using five M3x10 screws tighten the parts together in following order: Start in the middle and ensure proper alignment.
  • Using five M3x10 screws tighten the parts together in following order:

  • Start in the middle and ensure proper alignment.

  • Continue in the corners, tighten all screws equally.

  • After the tightening is done, push the filament sensor cable in the slot along X-carriage-back, join the remaining cables.

I had to losen the 2 top skews or els my length calibration wouldn’t finish.

Ian Warendorf - Reply

Hi Ian, can you please describe your issue? You can attach pictures as well (http://manual.prusa3d.com/Answers). Thanks

Jakub Dolezal -

I also found that self test will give X axis error when the five screws are tightened to much. Just tighten the screws until the seams between the printed parts close. All five, not just the top two.

Christoph Stahl -

Ian, my calibration would not finish either, it would error out on “X-axis length no long enough” (or something along those lines). Had a heck of a time diagnosing it, kept adjusting my belt thinking it was the problem but after a bit I realized it felt as though the bearings were jammed or not aligned properly (mechanical binding feeling).

Chris Wes -

Go to step 37/38 (Inserting the NYLON filament) and check if you do not want to do it now.

Michal - Reply

The (2) M310 screws were too short to catch the nuts for the top two points, I used (2) M318 from the E-axis bag that (as far as I can tell) aren’t being used anywhere else. They fit, they work.

Benjamin Curto - Reply

Hi Benjamin, I strongly advise against using different lengths of the screws. The design is tested several times before being released. Are you sure both printed parts are seated properly and there is no gap between them, which may result in “need” of longer screws?

Jakub Dolezal -

Confirmed, had to loosen screws to succeed in X-axis calibration, should be noted to tighten (all five) just until seams close then stop.

Benjamin Curto - Reply

Hi Benjamin, if the parts are seated properly, you can tighten them without affecting the X-axis calibration. What issue was causing your printer to fail X-axis calibration?

Jakub Dolezal -

I also had the same problem with the top 2 screws not screwing in all the way. The printed parts appear to be seated properly. I adjusted the middle screw and re-aligned the printed parts. The top 2 screws still had trouble catching the nuts and I had to apply a bit of force to get the screws to catch.

Alex Wilkie - Reply

I had trouble with the upper-right bolt not catching. I used an M3x18 screw to do the ol’ “pull the nut in” trick and after that the M3x10 tightened perfectly.

Cliff Miller -

Same here. My problem was that the nut for the cableholder (inside) was still standing out a little bit. I thightend the cableholder scre more so that the nut was more pulled in. After that, the back was fitting well.

Martin - Reply

This ^. There was crud inside the hole for the cableholder nut so it wouldn’t sit down right. Dismantled it, cleaned it now, now the nut fits nice and flush.

Mike Brookfield -

If I tighten all the screws for a flush fit, there us significant binding on the rails. I have to back the screws off until they are almost loose. The binding causes the X-axis calibration to fail.

Tim Deagan - Reply

The heads to the zip ties around the bushings were in the wrong position and interfered with attaching this piece. I ended up pulling the center screw through the back piece before I realized the issue.

The back is still held securely by the 4 screws on the corners. Should I stop the build and get a replacement, or is it ok to continue on and print out a replacement as soon as the printer is functional?

Adam Kawula - Reply

Hi Adam, if the X-carriage-back is held in place by 4x M3 screws, it is ok to finish the assembly. However, reprint the damaged parts as soon as possible and assemble the printer according to the manual.

Jakub Dolezal -

Jakub, you may wish to consider moving the insertion of the 5 square nuts M3nS from Step 3.11 to the beginning of this Step 5.35. These nuts are used only. Otherwise they will probably fall out during many steps before getting here (it happened to me with the central and one of the lower nuts, they dropped out unnoticed and I had a prolonged moment of panic when I discovered my two screws have no nuts to grab on). This can quickly become a big problem for the unaware and inexperienced first time MK3 builder. These 5 nuts are very easy to insert at the beginning of Step 5.35, just swing out the X-carriage latched on at the top by two zip-ties, slide temporarily the single linear bearing away, and you have full access to the nut slots. Anyhow, these 5 nuts are required only here, far, far away from Step 3.11…

Alan Rusyak - Reply

I second this. The placement of the 5 square nuts makes much more sense around 5.35!

Corey Dangel -

One of my square nuts fell out and was missing by the time I got to this step. I agree that they could be inserted later in the process.

Harold Toler -

Minor nit: as in the rest of the manual, pictures of the 5 m3x10 bolts below one with green arrow four with orange.

timcdoc - Reply

I had trouble getting the center bolt started, starting the other 4, then using a longer bolt in the center just to start the threading solved the problem. probably just a bit of plastic fluff. I did not have to snug the longer bolt.

timcdoc - Reply

If the X-carriage-back is way too high, go back to the nylon insertion step and make sure you’ve placed it in the correct spot.

Brien C - Reply

Doh! We inserted the nylon filament into the wrong hole a few steps back. They nylon must go into the hole very close to the lower single linear bearing, beneath both levels of belt. Somehow we put it in the hole with a nut listening inside, above, which is needed for screwing the back plate on , with the result that the back plate couldn’t possibly close up on the extruder (the nylon would have needed an impossible path), and we were scratching our head for 5 minutes wondering if the nylon could possibly be taking such a tortuous path. No— the nylon feeds through this back plate easily.

Jonathan Histed - Reply

I initially had problems getting the x-axis carriage back closing properly. Messed about for a long time until I realized that the cable-tie heads securing the 2 bearings (installed in chapter 3 step 12 earlier) were rotated down. Because of the ‘lumps’ behind ithe back cover, it made closing the back cover impossible. As soon as I rotated the heads to point upwards, closing the back and attaching the screws was easy.

Perhaps it’s a good idea to mention this and also in the earlier step (i.e. 3.12).

Patrick - Reply

Just a precaution for this step, after tightening the 5 screws on the back cover of the X-carriage, the carriage stopped moving. I checked the cable routing, etc., but everything was according to the pictures. I loosened all 5 screws give or take equally a turn or two and carriage movement returned to normal.

Michel C - Reply

Keeping the bearings in place with cable ties is ok for the moment. however I would like to see a future improvement by keeping them in place with the back cover.

Klaas - Reply

Wrap the spiral wrap (the largest and the longest one) around the cables and the nylon filament. Start with cables from the upper part, after 3-4 turns (not more!) slide the wrap on the cable-holder. If possible, press the wrap slightly in the X-carriage-back.
  • Wrap the spiral wrap (the largest and the longest one) around the cables and the nylon filament.

  • Start with cables from the upper part, after 3-4 turns (not more!) slide the wrap on the cable-holder. If possible, press the wrap slightly in the X-carriage-back.

  • Don't wrap the entire cable bundle now, we will get to it later.

Jakub, it might be good to mention here that only 3-4 initial wraps should be done, as later the hotend cables need to be added. As it is, in my eagerness I wrapped the whole length of the spiral wrap (silly me!), only to have to undo it later (Step 42) to add the hotend cables…

Alan Rusyak - Reply

Hi Alan, step description updated. Follow the manual (pictures and text) and you will be fine :)

Jakub Dolezal -

My kit didn’t have a long piece of spiral wrap in it. Instead there was a length of a sort of curled up plastic sheathing. ???

Bill Wightman - Reply

Edit to my previous comment: My kit DID come with the textile sleeve, which was used to wrap the wires from the heat bed to the PSU. I didn’t see any spiral wrap long enough to handle the wiring from hotend to PSU…

Bill Wightman - Reply

Hi Bill, in case you are missing the spiral wrap, which is used for the extruder cable bundle, please contact our support using email info@prusa3d.com or via live chat at shop.prusa3d.com

Jakub Dolezal -

My center screw is all the way in, but spinning freely, not biting on anything. I think I may have stripped something. Is this going to be an issue? Everything seems solid despite that.

Ben Fillmore - Reply

Dang. This comment was supposed to be on the previous step.

Ben Fillmore -

Hi Ben, there should be nut in the “middle” of the X-carriage to which this screw connects, remove the X-carriage-back and have look. Anyway, as long as the other four screws work, you should be fine. You can also reprint the X-carriage in case the slot for the nut is damaged and allows the nut to rotate.

Jakub Dolezal -

Could you add a note or ProTip that users will complete the wrapping in step 41? Might save some time and frustration; seems logical to finish wrapping in step 39 and some folks dont follow directions explicitly. Just a thought.

Jeremy - Reply

Hi Jeremy, note added to all the steps, where spiral wrap is used. Thanks for your suggestion ;)

Jakub Dolezal -

at first I thought I did not get the spiral wrap, but it turned out to be inside the cylindric box in which the rods came in, so if you can’t find yours, try to search there…

Eyal Peleg - Reply

I think it would be very helpful for builders to know how important it is NOT TO PINCH THE PINDA PROBE CABLE. I am 3 weeks into using my MK3 with zero issues and suddenly my nozzle jams into the bed one print and cant detect Z distance. After troubleshooting PINDA issues I discovered that after cutting 5 of my zip-ties and removing the spiral sleeve for the wires that my PINDA cord was being pinched in the center of the grouping causing it to fail. I would suggest everyone consciously keeps the PINDA cord running nicely alongside all the rest of the cables and not snaking through the center of the bundle. Make sure you do not also over-tighten any of the zip-ties that hold your wire bundle in place nearing the final steps of the build guide.

Zach Kirk - Reply

Use three zip ties and push them through the lower slots on the cable-holder Check for the last time both the wrap and cables are seated properly.
  • Use three zip ties and push them through the lower slots on the cable-holder

  • Check for the last time both the wrap and cables are seated properly.

  • PAY GREAT ATTENTION to the final position of the zip ties. If you don't follow the manual, you will have issues during prints!

  • Tighten first zip tie on the side of the cable-holder and cut the zip tie as close as possible to the printed part.

  • Tighten second and third zip tie on the top, but note they both must be slightly to the left. Cut the zip ties as close as possible to the spiral wrap.

  • Don't wrap the entire cable bundle now, we will get to it later.

With the cable ties in this exact position, the top square part of the ties was bumping into the PSU frame, preventing the X axis from moving all the way to the right, and resulting in a self test X axis failure. I had to rotate the ties so the square part is positioned directly on top of the cable bundle instead of slightly left.

Jason Livingston - Reply

I confirm, that’s the case with the middle zip tie. The outers don’t cause any problems.

https://tinyurl.com/y9bjfvg2

Heiko Schultz -

Hi Jason, can you please post pictures of your setup? We've tested the zip tie layout several times to ensure, it works.

Heiko (@predatorjr) you zip ties are not aligned as described in the manual, please recheck this section.

Jakub Dolezal -

I had a similar problem. I had to move the zip tie closest to the extruder to avoid it hitting the frame and causing the self test to fail. It was exactly as the images (but the zip tie was trimmed flush on mine, which should be the best case for clearance). To fix it, I did as Jason suggested and moved the square part of the zip tie to the top of the bundle.

Steven Underwood -

I had exactly the same issue with the zip tie closest to the extruder. Moving all the heads to the top solved the x-axis calibration error.

Orne Brocaar -

I can confirm I had the same issue as Steven. Moving all zip ties to the top fixed the issue.

Paul Betz - Reply

Both of my MK3s had the same issue as well. All 3 zip ties have to be in the top position for the X-axis to work properly

Ezra Scott - Reply

I tried following the directions but experienced an x fail so I listened to the comments and now it works properly.

Kyle Campbell - Reply

Same here, X text failed. Orange arrow, innermost zip tie hitting frame when placed as shown above. With all zip tie ratchets on top it works just fine.

J Allen - Reply

Guys, thank you very much for the feedback, we will rerun our tests again and make adjustments to the manual.

Jakub Dolezal - Reply

Same here. Had X-axis failures until I moved the zip tie heads on top.

The description is very specific in getting the closest zip tie to be on the side otherwise “you will have issues during prints! “. I couldn’t figure out what these could be. Could you elaborate?

LaurentR - Reply

Hi Laurent, for certain geometry of spool holder the “closest” zip tie can cause crashing of the Extruder in the top position, that is we advise to move it on side and cut the as much as possible of the overhanging part.

Jakub Dolezal -

Same issue with zip ties here, solved by rotating all heads to top or bottom of wire bundle.

Bruce Moore - Reply

Well, what should I do then? Follow the pictures or comments? Has anyone ended up with a functioning system following the manual?

I-Man - Reply

It did work just fine for me as set forth in the manual. Wizard sailed right through.

Twerd -

Like the other builders I found that I needed to rotate the zip ties to the RIGHT so that they did not protrude over the lefthand side of the cable support assembly. Doing this cured my X axis failure found on running the Wizard.

Phil Higgins - Reply

I too had to move the zip ties to the TOP. Weird this hasnt been updated yet.

Alex Tutusaus - Reply

With the greatest respect to the awesome job that Jakub has done in preparing this manual, I have to agree with all the other builders that if you follow the instructions for this step, the zip ties will hit both the left and the right frame. Fortunately, there are multiple locations to put the zip ties through, and it really doesn’t take much to secure the cable wrap by using the positions further away from the extruder, and everything is awesome …

Bob Hardy - Reply

Instead of zip ties you can use some black heat shrink tubing. Electricians and people working with electronics all use them.

Klaas - Reply

If the zip-tie closest to the extruder assembly is towards the top, it can hit any accessories mounted on the top of the frame … like the spool holder.

I used the orientation shown, and trimmed the end of the zip-tie perfectly flush, using a new and very sharp Exacto blade. The tie does hit the frame at max X-position (i.e. it acts as the end-stop), but this doesn’t seem to matter, as it is outside the print area.

Do make sure the zip-tie is as tight as practical, so that it doesn’t bulge.

Andrew E. Mileski - Reply

I avoided the above problem by using (by accident) the upper zip tie hole (second hole from X axis) instead of the lower first hole for the upper zip tie and the first hole for the lower zip tie. I positioned the zip ties as shown in the diagrams. Moving the X axis all the way to the frame I find no zip tie interference. I have not self-tested but a gap is evident so no problem is anticipated.

Gary Shumway - Reply

Use two zip ties and push them through the upper slots on the cable-holder. ATTENTION! Before tightening the zip ties add the cables from the hotend. Once the hotend cables are included, tighten the zip ties and cut remaining parts.
  • Use two zip ties and push them through the upper slots on the cable-holder.

  • ATTENTION! Before tightening the zip ties add the cables from the hotend.

  • Once the hotend cables are included, tighten the zip ties and cut remaining parts.

  • Don't wrap the entire cable bundle now, we will get to it later.

Be sure to place the clamp part of the zip ties at the bottom of the assembly, as shown in the picture. If the clamp is on the side, it will interfere with the full range of motion of the extruder in X and Z.

Jay Sinnett - Reply

Trim that first zip tie close (the one with the clasp on the left). Too long a tail can hit the PSU/frame and interfere with the x-axis length test during callibration.

Vince - Reply

Make one more turn of the spiral wrap, then add the cables from the hotend. Wrap the whole cable bundle.
  • Make one more turn of the spiral wrap, then add the cables from the hotend.

  • Wrap the whole cable bundle.

This cable management is so clean and wonderful! I always struggled to get the mk2s as clean as I wanted it to be, for me this is a very nice improvement (as well as so many other “small" improvements in addition to the new features).

Steven Underwood - Reply

Hi Steven, I'm glad you appreciate the update to the cable management ;)

Jakub Dolezal -

At this step I realized the thermistor’s heatshrinked wires were both between the hot-end and the heater wires, and actually touching the hot-end block.

I had to snip the tie-wrap bundling the wires together, and very gently re-route the thermistor wires on the outside of the wire bundle. The heater wires are much more heat resistant with their fiberglass braid and silicone sleeves, which can also serve as insulation for the thermistor wires from the heater wires (the heater wires get hot near the element).

There really should be a note in the instructions to watch for this, and perhaps a step to ensure the wires are safely routed.

Andrew E. Mileski - Reply

I talked to Prusa support and the guys assured me that both cables are made of heat resistant materials, so no need to worry that hot end will damage them. Cheers fellas

Artem -

I’m tempted to remove the tie-wrap closest to the carriage, as it is within the the frame.

The “head” of the tie-wrap acts as an end-stop at the max-X position, striking the frame before the carriage does. It probably isn’t a good idea for this part of the carriage (and the wire bundle) to be taking repeated hits.

The min-X position is not a problem.

I think I’ll first try replacing it with a smaller tie-wrap with a smaller “head”.

Andrew E. Mileski - Reply

For the following steps, please prepare:
  • For the following steps, please prepare:

  • Idler-plug (1x)

  • Filament-sensor-cover (1x)

  • PTFE tube (1x)

  • M3x10 screw (2x)

Where am I supposed to find that PFTE tube cut?

Alex Tutusaus - Reply

in the bag “5. E-axis”, it is together with nuts and bolts

Jakub Dolezal -

I believe my printer kit was shipped without this Idler-plug. It was not in the bag labelled ‘E-axis’ where it says it should be. Is this part something I can print later once the printer is operating?

Patrick Lynn - Reply

Hi Patrick, the idler plug can be printed later on. Download the MK3 bundle from here: https://www.prusa3d.com/prusa-i3-printab...

Jakub Dolezal -

It will be extremely helpful if you guys add the specific measurement for the PTFE tubes both for the hotend and the one for the sensor cover they can get easily damaged and you will need to replace them but is hard without the proper measurements.

Cesar Lopez - Reply

Hi Cesar, for the hotend please use this guide: How to trim PTFE tube - MK2/S, MK2.5 and MK3 I will add the tube for filament sensor soon.

Jakub Dolezal -

It appears my kit did not come with the PTFE tubing. I contacted support, and they are sending a replacement. I have some tubing laying around in the meantime. Can you please share the tubing’s specifications so I can try to create my own?

Julio - Reply

Hi Julio, I'm sorry I don't have the drawing for now, but I will make it asap and share it here on Dozuki.

Jakub Dolezal -

Locate the largest circular opening for the PTFE tube on the top of the Extruder. Push the PTFE tube in. Most of the tube's length will stick out.
  • Locate the largest circular opening for the PTFE tube on the top of the Extruder.

  • Push the PTFE tube in. Most of the tube's length will stick out.

  • In case the PTFE does not hold properly in the hole, you can assemble it to the cover first, BUT MAKE SURE there is no obstacle in the hole as you can easily deform the tube while placing as a part of the cover.

If you have clumsy hands like me go ahead and put the PTFE tube in into the filament cover. It will stay in place that way when your putting the cover on instead of flying across the room when your hands slip.

Paul Betz - Reply

Hi Paul, the PTFE tube is made from rather soft material. We suggest our way of assembly to prevent damage to the tube in case there is an obstacle in the hole. If you use cover, you can introduce much higher force and deform the tube.

Jakub Dolezal -

I reached the same conclusion as Paul, possibly for a different reason. The PTFE tube did not fit ‘firmly’ in the hole in top of the extruder, it just wobbled about loose. It looks if I tried ‘pushing’ the tube in, expecting to find a firmer fit, I might have tried pushing it hard against the side of the imaging IC on the filament sensor which seems risky.

For my parts, as far as I can tell there wasn’t an obstacle in the hole, much the opposite, it was too loose, and I couldn’t ‘push’ the tube into the extruder, rather just ‘rest’ it in there. I pushed it into the cover instead to get things to align, and the cover screw down without a problem.

I agree this was quite possibly a bad idea as in trying to debug what happened I find I cannot pull the tube back out of the cover, suggesting it is quite tight. I’ll see what happens, and don’t have specific suggestions for others following the instructions.

Kenneth Albanowski - Reply

I did the same as Paul and Kenneth and found this a better way than placing the PFTE in the hole first (it was wobbly and didn’t go in too much). I took it apart again to check for any damage and didn’t see any so I believe it’s a safe bet in case you can’t for some reason do it as per manual instructions.

Florian Ford - Reply

This step confused me. I was determined to try to do this the recommended way and placed the PTFE tube in the Extruder but wasn’t totally sure of its placement. I fumbled around and the placement is definitely not obvious until you place the cover on. I almost thought I had a blockage and was ready to drill it out until I test fitted the cover. FYI the correct placement of the tube is in the large hole as shown (not next to the round hole where the thing looks like it may have room to go down further. Nope. It sits in the (slightly too large hole) about 3.8 mm deep and rests on a tiny little shelf which to me was so small that it looked like a blockage from printing the part. So yeah, go with Paul and Kenneth or perhaps modify the part or description please!

Andreas Sjolund - Reply

Hi Andreas, step description updated. Anyway we’ve tried several approaches and it is easy to deform the tube if you press it down as a part of the cover. You have to be very careful.

Jakub Dolezal -

I used a 3” piece of 1.75mm filament to align and make sure there was no bind when tightening down the top.

Frank De Abreu - Reply

There is a few typos in the information notice:

In case the PTFE does not hold properly in the hole, you can assemble it to the cover first, BUT MAKE SURE there is no obstacle in the hole as you can easily deform the tube while placing as a part of the cover.

Gael Lafond - Reply

Hi Gael, thank you for the feedback, text corrected ;)

Jakub Dolezal -

Hi Jacub

Please change the sentence “Push the PTFE tube in. Majority of the tube's length will stick out.” to "Push the PTFE tube in. Most of the tube's length will stick out."

Klaas - Reply

Hi Klaas, thanks for the rephrasing ;)

Jakub Dolezal -

Carefully slide the filament cover on the PTFE tube. Using two M3x10 screws mount the cover.
  • Carefully slide the filament cover on the PTFE tube.

  • Using two M3x10 screws mount the cover.

The button right screw does not fully tighten. It does not stop rotating but it hold the cover in place and does not rotate freely. I’be tried to back trace the installation steps in the manual and could'nt find where the insrucation of the nut is? Is it missing?

יוסי שלי - Reply

Hi, there isn’t any nut hidden in the Extruder body. Both screws should “bore” in the printed part of the Extruder, this is enough to keep the m in place. Please check the cover isn’t able to move and let me know ;)

Jakub Dolezal -

Suggestion - *any* time a screw is going to be “self-tapping” into plastic, please note something in the instructions like, “This screw threads into plastic - tighten until firm but do not over-tighten or you may strip it!” Since nuts are used to capture screws in so many places, it’s very easy to be too strong on a plastic-threaded part.

Bill Magley - Reply

I agree with Bill. The self tapping screws should be documented.

phr0ze -

Locate the part, where the idler is cut out (M3 screw is visible). Assemble the idler-plug and ensure it fits properly. Otherwise, it might fall down during the print.
  • Locate the part, where the idler is cut out (M3 screw is visible).

  • Assemble the idler-plug and ensure it fits properly. Otherwise, it might fall down during the print.

Can someone explain the purpose of this plug? Is it just for looks or does it serve a function?

Paul Betz - Reply

Hi Paul, the plug prevents dust and other particles from the reaching the sensor.

Jakub Dolezal -

I found myself asking this same question.

Joe

jperch - Reply

Hi Joe, the plug protects the sensor. See my comment above.

Jakub Dolezal -

If the cut out on the idler must be closed to protect the sensor from dust, then why is there a cut out in the first place?

Levent Alpsal - Reply

^^^ good question!

Lyubomir -

I’m not certain, but I think it provides a port so you can use an air duster to blow out any dust that might get on the sensor.

Bill Magley -

A very good question!

David -

I think, that this cut-out is to have a possible check on the sensor.

Leo -

Hi Levent, you need to be able to check the sensor visually.

Jakub Dolezal -

It would be nice if there was something holding it in place.

Ray Benjamin - Reply

For the following step, please prepare: Fan-nozzle (1x) M3x10 screw (1x)
  • For the following step, please prepare:

  • Fan-nozzle (1x)

  • M3x10 screw (1x)

  • Carefully slide the X-axis up so you have access to the lower part of the Extruder.

  • Release slightly both screws on the front print fan.

  • Assemble the fan-nozzle and tighten all three screws.

  • In case you are missing M3x10 screw, please use one from the spare bag.

I do not have M3x10, I have two M3x18 and one M3x30. The package contained only 9 pieces of M3x10.

Michal - Reply

Same, but I had an extra from a previous step so I didn't have to dip into the spare bag.

Steven Underwood -

Same with me too. I had two extras from a previous step. I keep winding up with extra screws or missing some so I keep second guessing myself thinking I screwed up somewhere.

Paul Betz - Reply

Same here. 2 m3x18, 1 m3x30, no m3x10. Stole a spare from previous step.

Paul Meyer - Reply

Same here. Spent a fair amount of time retracing my prior steps to see if I’d made a mistake.

Brandon Oprendek - Reply

Step description updated, in case you are missing screw to mount the fan-nozzle, please use the spare bag. I'm sorry for the issues.

Jakub Dolezal - Reply

What was the purpose of loosening the print fan ? For me the part seems to fit correctly regardless.

Chris Pardy - Reply

Hi Chris, to align nozzle and fan it is better to have them both loose.

Jakub Dolezal -

missing M3x10 also.

Josh Miller - Reply

Step 35 I’m fairly sure was supposed to be (2) M3x18 for the top two points (not M3x10), that’s what I used and now I have this M3x10 free for this step.

Benjamin Curto - Reply

Hi Benjamin, screw lengths have been checked several times, they are all correct. Some early MK3 kits might be missing this M3x10 screw, but you can use one from spare bag.

Jakub Dolezal -

Missing here too

Alistair - Reply

No 10mm screw left but, as mentioned before, there were a couple left from previous steps that seemingly had extra. For me the fan duct went on with absolutely no effort and screwed in right away. I checked it from all angles, it went on as it should have so no blower fan touching for this step..

Florian Ford - Reply

When I slide up the X axis its much easier to slide up the right side compared to the left (where it feels much safer to turn the screw with my fingers since its so difficult to make the motor turn. Is this normal?

Andreas Sjolund - Reply

Hi Andreas, the amount of force needed for turning left and right side should be the same. If you observe the printer has issues during prints to move the axis up, please contact our support.

Jakub Dolezal -

Why does it say “HOT!2”? I get the “HOT!” part, but why the 2?

Bas - Reply

That is a mystery and only Josef Prusa himself knows the answer :)

Jakub Dolezal -

My plastic fan nozzle was not alligned nicely, so I used a bit more force on the screw and then it broke. Fortunately, printing goes fine without it.

Edwin Martin - Reply

I had the M3x10, but I also wound up with an extra M3x30 and two M3x18 screws. I’m pretty careful about not missing steps, and I don’t see anything obvious, so I’m going to assume they are just more extras for the spares bag!

Bill Magley - Reply

The bottom entry to the fan housing split as I was re tightening it. Didn’t seem like it increased in resistance at all while I was screwing it it, just started splitting down the side.

Yeah the opening was large enough to allow the screw head to enter and split it. I’m going to try a small washer to get some tension there.

Evan - Reply

I am lacking a critical and yet common piece. I have looked everywhere, including the spare bag. Is the M3x10 spare, in the spare bag, the same as the M3x10 that are not in the spare bag?

Bleak Disclosure - Reply

Hi Bleak, the M3x10 screws should be included for each chapter in a bag with appropriate label. It might be my colleagues forgot to include this one for fan nozzle. In such case please use the spare bag (nr. 9) and use M3x10 screw from there.

Jakub Dolezal -

Alignment issue. The fan nozzle was not horizontal, with about 2mm difference between left and right. The right side was not high enough because it touched the clip on the fan housing. Cut that clip partly away and now a nice fit.

Rob Veenendaal - Reply

Perhaps you can print the lower right screw-hole for the fan nozzle with a thicker perimeter? I tightened my screw too tight and broke it w/o even noticing the screw was fully seated due to the low resistance.

tim - Reply

fan-nozzle is not horizontal, its down on one side and seems to occasionally catch the print.  I cant get the screw to fully tighten, its always a bit lose.

patrick robinson - Reply

Have a closer look at the right picture: Note the text “HOT!2“ and see that there is undesired contact between the two parts just above the 2. That is why the fan nozzle is not horizontal. Easy fix is to just cut away a tiny bit from that clip on the fan housing.

Rob Veenendaal - Reply

IMO this part is not very well designed (compared with the rest).

To fit the fan nozzle I had the move and coerce the hot end cable to lie in a very specific way. But evenso with only 1 mounting point the height of the ‘other side’ (below the centre of the fan) is below the level of the nozzle. I expect I will need to remove this part once I start printing?

Suggestion : a part could be designed to share the 2nd fixing on the Front print fan. This would give 2 fixings on the same plane, much better robust design..

Mike Norman - Reply

After closer examination I found that the Fan nozzle was touching the corner of hot end. OK the heat would fix this during the first print, but the fan nozzle might foul with the printed part.

So some judicious filing to the foul area on the Fan nozzle, and also where the hot end cable lies improved the seating of the part. It now sits perhaps not perfect, but very much better. The hotend nozzle is now lower than the fan nozzle.

Mike Norman - Reply

Are we there yet? Almost! You've just finished the hardest part of the assembly. Awesome job!
  • Are we there yet? Almost! You've just finished the hardest part of the assembly. Awesome job!

  • Check the final look, compare it to the picture.

  • Checked everything? Let's move to: 6. LCD assembly

Why no gummy bear?

David Naoum - Reply

I assumed gummy bears to be already eaten :)

Jakub Dolezal -

The hardest part and we don’t even get one gummy bear? That felt like it was worth 3 gummy bears

Josh Miller - Reply

Josh if you have some left, then definitely treat yourself ;)

Jakub Dolezal -

You’ll be 3D printing gummy bears in no time.

Andreas Sjolund -

I was also sad to not see the gummy bear instruction in the manual. :(

Paul Bowers -

Man this was sooo complicated and definitely hardest so far… I am kinda scared about reaching to different parts should the need arise… like if we want to take the belt away, or if it’s still too loose (skipping steos), etc etc … it would be such daunting to take it all apart. I believe at least access to the belt’s insertion onto the X Carriage should have been granted by design.

Florian Ford - Reply

Hi Florian, the Extruder is the hardest part indeed and we are listening to your feedback, so currently testing new parts for easier assembly and maintenance ;)

Jakub Dolezal -

Cannot suggest a time. However Cook me 1:45

Alexander Buschek - Reply

Holy cow. I rewarded myself 5 gummi bears for that. Praying that there is nothing to be redone, this was rough.

Dieter Rosch - Reply

Pheew… Glad it’s done :) I would suggest around 2h assembly time.

Francesco Santini - Reply

We took 1 hour and 46 minutes. However, that included a long search for a Stanley knife to thin the end of the 3mm filament as we were struggling to fit that into the hole. That was by far the hardest part of the entire e-axis operation, otherwise it was great fun.

Joe Pirozzolo - Reply

My son saw the gummy bear package and asked if he could have one. There are none left. :( :)

Mr Gnome - Reply

I'm sorry, but the Gummy bears are only for those who participate on the build :)

Jakub Dolezal -

I have to say that was indeed the hardest part so far, lots of re-reading and looking at pictures, I even had to strip mine down twice to look for that “centre” cover nut… only to finally realise it was hiding between the belt ends.. arghhhh , but all done now..and still have some gummie bears left..

Martin Wright - Reply

The extruder is likely to be the most problematic part, and this configuration is quite intimidating to think about pulling it apart and having to replace/repair something. Almost worth the postage to send the printer back and have Josef fix it when it breaks. But, I can say one thing for sure…. it really looks cool at this point. I’m disappointed I didn’t get the Noctura tan/brown fan to cool the E3D. I received a Noctura, but it’s all black. :-( Minus one point for loss of the cool factor the two-tone fan would have had. I may have to order one for a replacement. Also, I almost ordered the all black printer. Glad I didn’t because the orange parts are perfect and really add to the first impression.

George Miller - Reply

2 hours. Kinda fun! I also build robots…this is similar but a little scarier as it actually will produce things ;)

By the way, where does the sticker go?

Christian Horner - Reply

Hi Christian, which sticker do you mean? In case of the silver one with QR code, then on the frame above the PSU.

Jakub Dolezal -

Only bad part for me was the Nylon filament. There had to be a better way to do that, even when done right it feels jury rigged.

Will Clay - Reply

Finish Line

573 other people completed this guide.

Jakub Dolezal

Member since: 02/20/2017

81,744 Reputation

134 Guides authored

68 Comments

Step 32-33: first you're tinkering with the filament sensor, then the next step is to pull a cable through the x-carriage back…

Took me a while to figure out that it was the - extruder- cable and not the- filament sensor cable-.

It is written, but just looking at the drawings, I was sure it was the same cable. Oh well RTFM to me :-p

Kenneth - Reply

Hi Kenneth, I'm sure you wanted your printer up and running asap and this is were some mistakes happen :) In case of issues with the assembly, always double check the previous steps.

Jakub Dolezal -

An hour and a hlaf, that part was pretty tedious. Putting the nuts in at 16 & 17 could probably be pushed down in order some. They were n’t used till quite a bit later, and kept falling out.

Scott - Reply

Step 28 needs a warning, some how I stripped the screw or it somehow the nut froze on the screw which led to the nut free spinning in the part. I ended up having to print another part.

Mike Carr - Reply

Hi Mike, can you please upload pictures or video? You can place them here: http://manual.prusa3d.com/Answers Thanks :)

Jakub Dolezal -

I had the same problem in step 28. Surprisingly he nut seized on the M3x10screw. Luckily I could still use the part because the nut had not fully bottomed in the hex when it happened. Removing the head from the screw to get it out was a bit of pain though.

Bo Gustafsson -

I had the same problem. I believe this step should be removed as the nut will be retained during, what is currently, step 30. I will also have to cut the bolt head off and I have not determine if I will need to reprint the part yet. Maybe in the future these components should be reviewed to relocate the retainer nut so that it is not so close to the bottom x bearing housing. I may reprint this piece with the wire harness bolt moved down 1-2mm.

Regards,

Jeff Underly -

I had the same problem with one “M3n” nut. Not sure how this might happen, but it seems that particular nut is not Metric - I tried it with several screws, the same behavior… I put that nut aside…

Alan Rusyak -

Step 40. Read the comments or there will be collision problems.

Bo Gustafsson - Reply

Anybody end with extra screws? I got two m18 and one m30….short with one m10 and took from spare.

Bill D - Reply

Yes, I had exactly the same amount of leftover screws.

Tomi Orava -

same here…………

Mike Cohen -

+1

12 characters

D Wellnitz -

Yes, one 30, two 18 and the itsy bitsy hex nut for the extruder

Philippe Lacoude -

Same for me, 2x M18, 1x M30

Leo -

Same, 1x M3x30 and 2x M3x18 left over.

Kit packaged on 2018-04-30.

Smoere -

Bondtech claims you should add grease to the shaft for the needle bearing.. am i missing the step in the instructions or shouldnt i add grease?

Daniel Hellström - Reply

Hi Daniel, during the assembly no grease is needed, only for later maintenance.

Jakub Dolezal -

I added a small amount of high temperature grease to each bearing. Just didn’t seem right putting them in there dry.

E Duane Rose -

To add my two-cents worth to the lubrication discussion: According to the Bondtech document “Assembly Manual QR V1.6 2016-03-24”, the bearings are shown pre-installed into the Secondary Drive Gear and are almost certainly pre-lubricated. They later go on to state “…apply some grease…” in the maintenance section on page 9. This would lend evidence that these bearings should be lubricated. The reason they only state to apply grease during maintenance is because the bearings are pre-lubricated/pre-installed. In the case of these instructions for the Prusa i3 Mk3, the bearings are NOT pre-installed and thus need lubrication. My vote is for lubricating the bearings prior to assembly.

example document: https://drive.google.com/file/d/0B7A1MEU...

MattP -

Step 22 was very difficult to get the hex screw to stay in place in the ‘arm’ for the air blower fan. Perhaps a longer screw? Or a square nut/slot style here? I ended up using a large allen key (same size as the nut outer diameter) to press the nut in and flat for the screw to bite.

Cameron Lamont - Reply

Agreed. That needs to be a 20mm screw, or the mating plate needs to be 2mm deeper.

Mark Crawford -

On step 35, I could not for the life of me get the M3x10 screws to work. I resorted to using the spare M3x18 screws, and they worked like a charm. The problem was the M3x10 screws just werent long enough to get to the nuts for some reason.

Zachary Goyer - Reply

Th