PTFE Cutting Jig 45° / 60°

by vekoj Aug 22, 2018
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Hi, thanks for your jig. I used 45° 50mm for my DIY clone and worked fantastically.

Now I'm switching to MK3S extruder and I see your 45mm but reading on Prusa schematic it seems it should be 44.2 or am I wrong?

Seems they slightly changed the length, at the time I was making the edit I could swear it mentioned 45mm. I will make a 44.2mm version soon then.

New versions are uploaded.

Thank you so much...

Has anyone tried a version of this with a V cut in the 'gear' end to make flexibles less likely to spill out? I'm guessing putting a conical entrance into that might mess it up? Just having fun with Ninjaflex coming out the side at the moment. Guessing my current tube is a little short but haven't started disassembling to check yet.

Works great - thanks!

This is awesome - works great. Thank you! Also my 60 degree v-bit from my CNC works great in a cordless drill to open up the other end to spec.

Fixed. My fault...lol

Which hole are you referring to? Did you perhaps print it with supports on or something of the sorts?

Watching Chris's video on youtube about how to assembe the v6 correctly he said that the length should be arpund 50.7mm . will that make such a big difference ? and which version is the correct one ? 45 or 60 degrees ?

Around 50.7mm turned out to be 50.2-ish so it's very close to the gears, according to CAD drawings. However, that leaves very little room for tolerances. The nominal 50mm is just fine, the internal chamfer is a lot more important.

Until recently, Prusa instructed the 45° one, it states 60° now. Might be that some insights from the MMU2 led them to change it. I am not really sure. If they say 60°, I'd say go with that one.

Thanks . I'm gonna print it now and see how it goes :)

Because they changed it recently and I am hearing this from you. Initially they instructed 45°. If you read some of the comments below, the jig was 60° initially according to the findings I had, but changed to reflect the instructions in the very same link that states 60° now. My speculation is either there are slightly different heat breaks out there (according to the CAD drawings I was referencing, the angle differed from several manufacturers, though it might be just a CAD drawing mistake). Or, they concluded that even if the heat break has a 45° chamfer, the ptfe tube should be 60°, that way it has less chance to leave a gap between the ptfe and the heat break.

Will update the thingie soon-ish with a 60° version I had initially posted. Guess things have changed...

Many thanks for your great jig, hope to print soon 60° version

That's a good object. It cut a perfect 45° PTFE.
Length is not 50mm (measured stl confirm it's shorter) but I don't think this will be an issue


I like it. But why 60 degree cut instead of the 45 degree cut specified by Prusa? Is the chamfer in the heatbreak not 45 degree like I thought it was?

It's because every drawing indicated that the angle is 60°, even micro swiss V6 compatible ones. That is, until yesterday when the drawings were updated (https://e3d-online.dozuki.com/Document/I2woGboCqjNEBkIx/.pdf). I also compared my 60° chamfered tube with the stock one I got out of the pre assembled extruder I got directly from prusa, and they look identical. My reasoning was, they are instructing users to cut 45° because the method they suggest cant be precise, so they are giving some room for mistake.

I guess trying to "optimize" the cut a bit further was a mistake on my part, because at this point I am not sure if the "old" drawings were faulty, or the design changed over time... and if it did, which heat break has which -_-. For sake of keeping things simple, I will soon revert the jig to 45° because a 45° chamfered tube even on a 60° heat break is safer choice than the other way around.

I cant get the 60 degree to cut with this any ideas or tips

I tried to explain it all in the instructions, but.. Make sure the blade is 0.5mm and sharp. I used an x-acto knife.

Make a flat cut before insert the tube for the 60° cut.

Make sure to push the ptfe against the jig when you start the cut. Cut with the blade while the tune is inserted, then using gloves rotate the tubing (with the blade full inserted) like a pencil sharpener... make sure you rotate the tube against the cutting edge of the blade. While rotating the tube always push the tube towards the jig... try to use even force. When you complete the initial cut, if you didnt cut it properly, try to insert the tubing again while the blade is inserted, apply gentle pressure towards it and rotate.

If you arent satisfied even after that, better to start over than trying to fix it. Make a flat cut again and repeat the process.

Hi I'm sorry but I must be just stupid but I cant get this to cut the 60 degree to cut on this jig