ATTENTION!!! Please read all instructions at least twice! If you trim or drill the tube improperly, you will have to order it again!
  • ATTENTION!!! Please read all instructions at least twice! If you trim or drill the tube improperly, you will have to order it again!

  • READ CAREFULLY instructions for the tools before you proceed further. Prusa Research is not responsible for any harm or injury.

  • For trimming get a cutting tool with a thin blade. Use either razor or carpet knife. DON'T use kitchen knife.

  • For drilling is recommended to use a drill bit with conic head or you can use a drill bit with diameter 3,5 - 4 mm. The point is to make a conical entrance in the tube.

  • Do you have Multi Material? Use this guide instead: How to trim PTFE tube - Multi Material

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This an ideal shape of the PTFE tube for Original Prusa i3 printer. Given dimensions and angles are recommended values.
  • This an ideal shape of the PTFE tube for Original Prusa i3 printer. Given dimensions and angles are recommended values.

  • The ideal shape for the MK2, MK2S, MK2.5 and MK3 hotend.

  • The ideal shape for the MK2.5 and MK3 extruder (top part of the filament cover).

  • All dimensions are in millimetres.

Please indicate that this drawing is a cross-section. At first I thought I had to cut a slit out of the PTFE tube. Why is this step not in the normal assembly manual?

So, this brings up another question: in step 5-19 (pg.19 of 40) you say “The surface of the heatsink … must be aligned with the surface of the printed parts…” Mine does not. It’s one rib higher. Is this because I NEED to cut the tube (not mentioned in the manual)? I looked ahead in the manual to see if it might hit something by sticking up, but don’t see any reason it MUST be flush. Right / wrong? The hotend sits into the Extruder body in a groove and cannot go in any further. Right?

Thanks in advance. Speaking of thanks, I want to thank everyone there at Prusa. At the MAKER FAIR in San Mateo, CA they told me 6 to 8 weeks which would be about the second week of July. I’ve been in computer manufacturing and I knew that meant late July which means August! However, mine arrived, in my estimation, 3 weeks early!!! Thirteen thank yous.

Tom Heinz - Reply

Hi Tom, thanks for the feedback, I will change the drawings accordingly. In general you don't have to adjust the tube, it is done in the factory. This guide/manual is mainly for those scenarios, where the tube gets damaged during prints and needs a replacement. Your printer MUST be assembled according to the manual, otherwise it won't calibrate and print properly. If you can't assemble some parts together and you suspect a defect or incorrect dimensions, please contact our support at

Jakub Dolezal -

  • IT IS CRUCIAL to cut the correct end of the tube, check twice before you start!

  • One end of the tube has "rounded" outer edge. DON'T CUT this part.

  • Look at the other end, where the tube is drilled inside, shape of the edge is "conical". This is the side you CAN CUT.

im wondering what is the best method to round the end of the ptfe tube that goes into the heat break. I have a lenght of pffe tube which i can cut to size to make the inserts for the hotend.

John - Reply

Hi John,

I suggest to use pencil sharpener, it will create this desired rounded edge ;)

Jakub Dolezal -

E3D says to leave the side that goes into the hot end straight though.

“To make sure that the end of the PTFE tubing that will sit inside your hotend is square and flat, cut a slice off with a very sharp knife (a craft knife with razor sharp blade is recommended for this). “

Martin Cooper - Reply

So… which is better?

Jeff Spencer - Reply

  • Take the razor or knife and carefully trim the tube.

  • Don't press too hard during the cutting on the tube, you can deform the circular shape and this will lead to filament jam!

  • Optimal length is 50 mm for MK2/S, MK2.5 and MK3 printer.

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  • After cutting the tube to appropriate length, you need to renew the conical entrance.

  • Use the drill bit you've prepared in the beginning. You can use electric drill, but set it to low RPM and press very gently.

  • It is important to achieve smooth entrance, so the filament will slide in. Clean the tube from any particles, which might prevent it.

  • That's it! Place the PTFE tube back to the Extruder and continue with the assembly.

What is that type of drill bit called?

Douglas Shelfoon - Reply

It’s a countersink drill bit.

Eric Mathison -

You can also use this tool. This tool is also super to make a hole bigger in you’re prints.

Jerry Ent - Reply

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Jakub Dolezal

Member since: 02/20/2017

95,819 Reputation

153 Guides authored


Nice process update. I think the pencil sharpener and drill ideas make this much easier and safer to complete than the previous method. The additional photos and diagram are excellent as well.

Douglas Shelfoon - Reply

What is the precise length of the PFTE tube for a MK2 ?

Andre Laurendeau - Reply

Hi Andre,

MK2 and MK2S share the same hotend, therefore 50 mm and shape according to the step 2.

Jakub Dolezal -

Any chance we can get an updated how to replace the PTFE tube? The only information/guide I can find is obsolete, and seemingly requires cutting/trimming of the tube, which would render the tapering redundant.

Trevor Tennison - Reply

Hi Trevor,

yes the manual is on its way. First, we need to finish the new MMU upgrade.

Jakub Dolezal -

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