Ultimaker extruder gear upgrade

by xifle, published

Ultimaker extruder gear upgrade by xifle Apr 21, 2013


Replacement for the original wooden extruder gear.
I was not very happy with the existing designs as their teeth profiles didn't match the motor gear or they were non-symmetrical or it wasn't possible to fasten the stepper screws with the wheel mounted...

So I decided to start from scratch and build a new one.


- Very good fitting to the stepper pinion. It has involute teeth, matching the distance of the axes and the numbers of teeth.

- You can use this wheel with only one washer between the bearing and the gear to get maximum tooth contact area. (However opening the extruder clamp can be a bit tricky if you assembled it to close...)

- Fastening of stepper screws possible

- The backlash is very small if the stepper motor is aligned properly (might increase retraction quality)

- M8 Nut should fit in nicely.

- Design makes it a very rigid structure (even @20% infill)

- Prints without support material

10.05.2013: Now with thicker teeth. Can be printed without support material and no need for second variant. Thanks to Noctis for the hint!
Note: photos are outdated (they show version 1)
29.04.2013: Added second stl file for use with two washers. This one is easily printable without support material and has no clearance grooves.

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well done! :-)
Thank you very much! I just hoped someone else found this useful... :)

To the handle: I think it's usability is questionable with the current design - it might be very difficult to access the handle from all directions, especially if the printer is not accessible from all sides... When I turn my extruder wheel manually I grasp it at the teeth which works quite good although not being very comfortable either... What I thought about are some kind of "smooth teeth" next to actual gear.. But I'm lacking time to put more effort into this idea and don't know if it's even really necessary ;)

I created one, It took less time than I tought. Let me know what you think about it :)


Your gear still works great, this is one of the best things I have downloaded so far!

Oh, now I understand! Yes, a handle would be nice! Maybe I will create one. But I am not that familiar with 3D-modelling, so it could take a lot of time!

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No Support material needed... just print it and have fun :)
20 % infill is enough, layer height is not critical.

Mount it with the flat side facing outwards.


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lukasbieri on Jun 2, 2013 said:

what is the hole in the wheel for? Did you plan to make a handle or something like that?

xifle on Jun 3, 2013 said:

The hole is to adjust the position of the stepper with the wheel mounted. You should reach the two inner screws which hold the stepper by rotating the wheel. This makes it possible to correctly align the wheel (distance to stepper gear) for smooth operation.
But a handle would be a good enhancement :)

4gotten on May 29, 2013 said:

just printed this off, and can already say WOW. printed it 20% infill ABS, strong as a rock, started to mount it backwards then look @ the pics and realized the genius. this fixed my gear problems 100% (large gear was warped when i got it...it's gotten worse since then) and has a reduced area to of collision all in all a brilliant upgrade thanks!

LukasQ on May 10, 2013 said:

hey xifle

That is what I was looking for!

Can you make the teeth a little thicker on the outside / top, so that there's no need for support structure? (and Mirror Z)

The small cylinder would be eliminated. The contact area will still be max as possible.

xifle on May 10, 2013 said:

Hey Noctis,
I'm happy to hear this :-)
Thanks for your hint - that's a good idea. I've uploaded a new version of the wheel.

Austin on Apr 21, 2013 said:

It's interesting to see the clearance-grooves on the back-side of the gear. However, wouldn't it print more cleanly if if the near-side of the gear was made thicker so it could become the bottom of the print? (have a completely flat bottom)

xifle on May 10, 2013 said:

I'm sorry... guess you had the same idea as noctis, didn't get this...

xifle on Apr 21, 2013 said:

Hey Austin,
you're absolutely right, but one of my design goals was maximum contact area between the two gears. The clearance-grooves on the backside are needed to bring the wheel as close as possible to the extruder (with only one washer).
Maybe I'll create a second stl file in the next days without the grooves (for use with the usual two washers).