I’m trying to track down a replacement for the Z Axis Delrin Lead nut on a Shapeoko 2.
It doesn’t appear to be available anywhere, and the closest I seem to be able to find is this:
However I have no idea whether this would work, as this parts list is so old. Any ideas, or just go ahead and try this one?
That looks right — the only concern is the hole spacing Is there a drawing to verify that?
My suggestion would be to make a new one using a pair of square M8 nuts, a spring, a block of Delrin, and the suggestions for an anti-backlash design — using the steel nuts will remove the issue of needing a tap and tap handle.
@WillAdams Ok, so you are suggesting just making one from scratch, drilling a hole larger than the Z-Axis threaded rod, and slotting in two nuts instead? The only concern have there is the wear on the threaded rod from the nuts. But maybe some variation on that idea? Nylon nuts? Delrin nuts? But I like where you are going with this. I went ahead and ordered the Amazon replacement, but it will be December before it arrives. I may just try your suggestion first.
Yes, there were a couple of designs for this posted to the wiki and the forums — if you can source square M8 nuts, it would just be a pair of slots centered on the vertical hole.
That said, an 8mm threaded rod is cheap, so that’s an easy replacement.
There were a couple of designs for Acme thread leadscrew upgrades as well, and I believe the X-Carve folks have a Z-axis upgrade.
Is this any help?
@OldDude Thanks, this helps clarify the anti-backlash part. I’m sadly not in the AU, but I suspect the parts I ordered could be getting sourced from there. I do feel better knowing that this looks correct. I may still track down a block of Delrin and mill it out as WillAdams suggested. That store does look awesome though XD
It looks like I may do this, I can get a plastics company (Tap Plastics) to cut and drill the part for me. The main problem there is that they only carry the Acetal Copolymer, not Delrin. I don’t know if it will handle the stress of the z axis. I guess I could always ramp in to put less pressure on it. Anyone tried using POM-C?
I can’t use off the shelf components since it seems that everyone is using 2mm thread pitch now, and the original Shapeoko spindle is 1.25" pitch. Unless I just replace the original threaded rod, then it’s easy to get the ant-backlash pieces on Amazon. But won’t that throw off my calibration?
If you replace the M8 threaded rod, you will need to recalculate the steps/mm for the Z-axis, see:
