Prusa Z rod supports

I've solved the problem of the couplers. Link to the part in video description.

[www.youtube.com]

Hi, it's a nice design, but there are many parts like this one already and it is proven to actually make Z-wobble worse in a lot of cases. For example, in my town, the metalshops don't sell straight threaded rods. None of them is straight, which is terribly annoying.

Now, if your rod isn't completely straight and your machine also has a tiny misalignment, this constraining of the rod will amplify the misalignment.

The best solution still is to move the motors to the bottom. This solves the problem of the axes dropping down, and at the same time it still doesn't require the other end of the threaded rods to be constrained.

Hello Ohmarinus.

Actually, since the bottom of my design is not mechanically solidly coupled to the rods, it can and does move slightly. You don't see it very much in the video since my rods are very close to straight. When the carriage is higher up, then a bit more wobble is noticable at the end of the left rod, and the support simply waggles along with it.

It's hard to explain, but can you picture it?

Ok, so there was just enough constraint to cause noticable Z wobble. I've completely re-designed this now. New design works at the top, supporting the coupler and frees the bottom end of the rods.

[www.thingiverse.com]

[www.youtube.com]

Hey, cool you took the time to examine. I have to admit that I really like your workaround. Didn't think of hanging it like that, so it's a bit out of the box

For me, the solution still has been to mount the motors on the bottom, but your solution probably works just as well! I hope others use it

Thanks for the positive vibe Ohmarinus,

I thought about putting motors at the bottom, but I don't like the idea of putting that load on the steppers bearings. When those wear, you'll start dropping half steps and binding, and you'd have to replace the entire motor.

Now, when I build an I3 this winter, the motors will be at the bottom, but I'll just adapt my bearings to that orientation. Just have to tweak and print new brackets for the compression load vs the stretching load.