Prusa MMU2 PTFE Holder M10 Passthrough Adapter

by vertigo235 Nov 23, 2018
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PLA okay for this, or need to use PETG?

PLA should be ok. I used 870 PLA

This looks too good to be true! Tubes popping out of the mmu2s have been the bane of my life. Especially when the printer is sat inside an enclosure. I’m looking forward to giving this a go, thanks for sharing!

Nice design.....thanks for sharing.

I'm just about to install.

How do you know if the PTFE tubes are actually being seated correctly in the MMU, when you push them through the festo adapters?

It pushes freely until there is no resistance. The couplers allow you to push them in but they grip to prevent them from pulling out.

Thanks mate.

Yep.....I'm aware that the PTFE only passes through the festo fitting one way without resistance, but given this, I just wasn't sure how you ensure that the PTFE tubes are seated the required 1mm in the MMU2 body, prior to screwing the adapter plate in place.
It would be hard to set the tubes first and then install the plate, due to this resistance.

Install the plate first
Screw in the festos
Push in the PTFE as far as you can
Have fun

Screw the Festos in first. Then push the ptfe in as far as it will go. If I recall there is a tiny window in the mmu2 body where you can see the edge of the ptfe if you are really worried but I have never had to do this. You can just tell it has pushed far enough. I think maybe you are over thinking it.

Very good indeed, thanks very much

Thank you! Enough said.


Hi, I love this fix. having to hold 5 tubes all at once was a horrible idea.
however, I printed it and when I went to insert the tubes into the fittings (before even screwing the fittings into place) the tubes don't pass-through...
This is obviously not the fault of the part at all. but I would like to use this place to ask the people reading this to see what was the outer diameter of their tubes.
At first I thought my problems was with the fittings, but they are 4.02 mm - my tubes however are around 4.15 :(
Did I get bad tubes from Prusa?

What does this actually accomplish? Isn't it still compressing the PTFE tube on the other side of the couplers? Or was the outside edge a pinch point?

No it doesn't compress the PTFE on the other side , just guides it to the end. The coupler is what holds it in now instead of the compression.

Just installed this for my new MMU2S. This is an easy mod, and should be first on the list for any MMU2 owner! It would be extremely easy to install it on the initial build. Great part, thanks!!!

is this also needed at the mmu2s (latest) version have ordered the mmu2s so i dont know someone else has a mmu2s and knows if this is needed to make?

The mmu2s has the same parts as the mmu2 so this upgrade would still apply . The only changes for mmu2s are at the extruder.

Oke thnx gor this fast reply;)

Thanks! This solved the problem I was having with stringy tips.

Superb mod, I would say everyone needs to buy this if they want to make the MMU print easier. I was jamming nearly for each filament change. Once I bought festos with this part, boom, almost zero clogs. I HIGHLY recommend this.

how does this reduce clogs?

Mine kept getting stuck in the back, the filament was not sharp or straight for the regular print. Not sure why. It would work sometimes but then randomly get stuck in that spot. Putting festos seems to guide the tube better and thus the filament is a tad more straight. Since putting, Ive never had clogging issues in the back. But your results may vary.

A great mod. Thanks so much for sharing.

This is a great modification to the MMU2. The only feedback I have is to make the threaded area ~2mm deeper. I tried to fully seat the PC4-M10's and ended up splitting the part on the last 2 screw turns. This was on a part made with PETG as well (so durability shouldn't have been too much of a concern) I was able to reprint it once more and be more gentle the second time around.

With the prusa team would consider this upgrade, was so much easier to reassemble than trying to press fit 5x slippery tubes into the stock part! :D

Thanks for sharing.
Where did you get the threadspecification?
Do you have that as an OpenSCAD file you would want to share?


I modeled it in Fusion360, the project link is included in the "How I designed this" section. Fusion360 makes modeling threads easy, feel free to update and make your own version if you like. You can download the fusion source.

Got it. However what is the specification in F360 for the thread?
The reason I am asking is that I dug up this design: https://www.thingiverse.com/thing:311031 It also claims to be M10 bolts, but as I see it the thread is very different from what you have. This made me uncertain of what is what...

This design however does fit your M10: https://www.thingiverse.com/thing:1993384
So - I am on the lookout for a definition of the nut and bolt thread...


OpenSCAD ISO metric thread library / functions (updated)
by TrevM
Tapered thread bowden coupling PC4-M6, PC4-M10
by krtektm

M10x1 not M10x1.5

At least the "M10" couplings I recently bought weren't M10x1 but (apparently) BSP G 1/8" - slightly lower diameter and 0.9something thread. Somewhat compatible, though, as long as you fit metal couplings into plastic threads - but the current version of Fusion360 also has those BSP threads in the library.

Someone did a remix for the BSP threads.

Comments deleted.

I am certain that the design works with the prescribed fittings and that’s all I care about.

Appologies for the confusion - I have now investigated. Your model correctly uses a 1.0 mm metric thread pitch.
The problem is with the threadlibrary I was testing it against which does not quite produce the right M10x1 thread.
(The shaft is to wide and the slope not quite right either.)


Very nice! It's just what I needed to make it easier to remove the printer from the enclosure. Printed it from Prusa PTEG with normal settings. Fits perfectly to the MMU and the PC4-M10. I pushed the PTFE tubes all the way through because otherwise the filament will stuck at the transition where the PTFE tubes end in the original design.

This is brilliant. Printed and installed. Perfect fit. Thank you.

PLA is fine for this isn't it?

Should be fine, I used 870 PLA for mine.

Very nice design, thanks for building this. One think I couldn't understand, how deep PTFE tube needs to go in this adapter. If I use the fitting, the PTFE tube is not reaching to the end of the adapter. Just going incide the fitting. So I am not sure if filament can travel freely without any problem without tube reaching to the end of the adapter? Can anyone port a comment...?

PTFE goes all the way in for me (to the end). I suppose it is possible that your PTFE is slightly larger OD than what I am using, I have seen variations in PTFE diameters.

I try to explain the situation with an attachment...
Thanks for help.

Gotcha, these are the correct fittings that allow the PTFE to pass all the way through, I'll add this to the description.


Veeeery nice adapter. I have trouble with Prusa original so it could be solution. In Czech rep. where I live producers provide Metric thread only to max 7mm (M7) for 4mm tube. Bigger diameter they have thread G not Metric. Does it fits G1/8 thread? Can you share link of adapter which you used or specify PTFE holder? thanks Roman

Hi @vertigo235, I also have the problem finding fittings with a metric M10 thread.
In fact the two links you provided are fitings with an 1/8 inch NPT thread.
You can identify the NPT thread by the slight taper and the aplied white PTFE sealant.

Is it possible that you also used NPT fittings with your metric M10 tread? The difference in diameter is very minor.

I'm curios, because every design I find uses metric m10 threads but I only can find fittings with 1/8 NPT.
What I can find are fittings with metric M6 threads and tube pass through. Wondering why nobody uses this instead?

many Greetings

Thanks for your reply.
Looks like you are using 1/8 inch NTP threads with your metric M10 threaded design.
I'm actually happy to hear that this works ok :) because I can't find fittings with M10 treads.

I'm not sure how you can see that those are 1/8 NTP threads? Regardless those PC4-M10 fittings work with this design.

You can identify the NPT thread by the slight taper.
I have attached a screenshot where I have taken the image of the fitting from your first link and added parallel lines in Fusion360. This makes it really clear that it isn't a metric M10 thread.

The BIQU ones are also sold on the german amazon (where I live) and there is customer feadback which also states that this isn't metric M10.

Sadly the chinese manufacurers too often don't know what they are producing. :(

I printed one in ABS. Excellent design. M10 fittings fit perfectly and the tubes pass through easily.

This is a fantastic upgrade. Thanks!

Does this fix 602? I have my MK3 on the way from Prusa and would like to have that fixed asap. Thanks!

Yes, of course it does.