Thanks nophead!

I used 3 layers of heat-shrink that I had available, to an OD of 7.25mm.

Wobble is gone.

This part was my first 3D print because when building my prusa I put too much presure in the standard coupler. I wish I have seen this part here before because when the part finished printing and tested on the motor shaft it was compleately loose :'(. My solution at 2am was to sand the parts so it will fit but latter I put a little piece of cardboard to hold the motor. It is working but tonight I will try to print it again and use the tubing.

Thank you nophead :-D

my measured diameter with tubing in the motor is 6.5 - 6.6 mm ... how much it should be?

I'm using these with a rubber hose intended for using with glasses. I got mine at a rafting trip, it's a very soft, almost foam-like rubber. Even though my Z-Motors are bolted down, i get no wobble at all. :-D

Nice :) An extra advantage compared to the prusa standard is that it's usable even when printed on a poorly-calibrated printer.

This fixed ALL of my z-wobble / see saw. The motors do not move at all now. The only difference from this is that i use rubber tubing and clamped it down hard. It is the very tough "surgical tubing" available from medical, swimming equipment, sling-shot, etc.

The vertical corners on my prints are very nice and even now. No "repeating pattern" of slight differences any more.

8-) 8-) 8-) 8-) 8-)

Any reason for the plastic tubing on the motor shaft? I edited the .scad to make the motor coupling end a simple 5mm hole and just attached it directly to the motor.

For people who don't have rubber tubing lying around, I've used approx. 35mm lengths of elastic band wound round the motor shaft instead, and they seem to be working fine.

I ended up making these to replace the original prusa ones, which broke when I had a z axis crash (thankfully protecting the whole x carriage and frame from damage). This got me thinking that a version with a designed-in torque limit would work well as passive crash protection. It would be quite v
ariable depending on infill/material/calibration but if I get time I reckon I'll have a bash at making some prototypes to test the idea.

Anyway thanks for this major improvement on the original parts! :)

I used this version for my SAE PRUSA. I drilled out the screws to #6 and the main shaft to just under 5/16". I did this so I could press fit the motor shaft with the plastic tube over it to make it tight.

It actually worked out better than the original SAE part this is derived from. Tighter fit. Working on my first couple prints since the upgrade. So far so good!

Just finshed printing and fitting them to my Prusa. They work great, NO wobble at all.

I used 10mm OD PVC tube.

Thanks 8-)