C axis tensioner screw length?

[ehegenberger]

What's the recommended length for this screw, assuming a 400 mm belt? I don't have an extra long Allen wrench, so it took me nearly 20 minutes to get the wrong length screw in. While I'm waiting for the answer, I'm going to make a wrench extender for my next attempt. :)

[ehegenberger]

Here's the wrench extender for anyone else who's having trouble with the C axis tensioner. Fits a small flathead screwdriver.
Hex wrench extender.zip

[TheOnlyMann]

what does that actually screw in? i was confused why it was there, lol

[xobes]

Same!

[ehegenberger]

Well, Joshua hasn't exactly sent us a boxed set of Lego or Ikea furniture here, but I'm assuming it presses the "C-axis tensioner" against the motor body to tension the belt. :)
There's a recess for an M3 nut on the other side for it to press against. I'm also guessing that he had a set of really long Allen wrenches, and tweezers too, to put some of these things together. Maybe a general design rule should be that if you can't fit a package of sausages into an opening, it's too small to access for putting parts together. :)

[TheOnlyMann]

honestly thought it was supposed to be mounted on the screw holes and that only.
sounds annoying regardless
currently looking toward redesigning the bed if possible and honestly have no idea how to do it lol

[jyjblrd]

Yeah not my proudest design choice, the motor was originally meant to only use the 4 screw holes but I had issues with it slowly losing tension over time.

The screw was added as an afterthought, which is why it's in such an awkward position. (and yes, I do have a set of rather long allen keys)

Redesigns are welcome as always, that's why I made it open source after all.

The screw is prob 40mm

[ehegenberger]

It's still a thing of beauty, and your video hardly does it justice. So few parts, all put together so well and working in harmony! This is a huge contribution to 3D printing, as well as being a lot of fun to put together. :)

[Chuckles182]

I made a tensioner system that goes over the top. It uses four M3x12, two M4 Nuts, and one M4x20. It looks like there should be enough clearance for the C Axis belt. I'm using a 400 mm belt.
https://www.printables.com/model/1143127-4-axis-core-r-theta-c-axis-motor-tensioner

[ehegenberger]

Definitely over the top lol.
Very nice!

[jyjblrd]

Great idea, I like it