Misalignment

[alan 0]

We recently finished assembly. The rear block on the X-axis is striking the lead screw that moves the platform in the Z direction. The lead screw does not seem to be bent - rotating it does not change the clearance against the back block. Viewed from above, thru the hole over the lead screw, the screw does not center under the hole but sits a little (a few mm) forward. What is the problem and what is the fix? Also, we have part 8B left over. Where does that go? Thanks.

[mr_seeker 0]

Part 8B

Is the lead screw straight? Try rolling it on a flat surface.

There has been a replacement part 8B sent from UM. Normally you need 2 parts 8B, but sometimes they ship with a spare part (with a drilled hole).

[alan 0]

Thanks for the suggestion.

Yes, the lead screw is straight - I rolled it on plate glass - it's definitely straight.

I noticed, when looking down the hole over the lead screw, that the brass fitting that is the screw mount for the lead screw does not line up with the middle of the coupling over the Z-motor. The brass coupling hole is a few mm forward, which would push the lead screw forward, into the block. This could be the root of the problem. I cannot tell why this is. Any ideas?

[approx 0]

It might be helpful if you can post a photo/pic showing the issue?

[destroyer2012 0]

I've had this issue. It's because the captive nut is too far forward. Try pushing it back/ turning it so the flats on the nut are parallel with the left-right axis. That whole nut trap thing is in severe need of some bolts or something... because it's super flimsy. Might want to take out the nut trap and sand it a bit to make the square holes a bit wider. The nut should slide side to side but NOT up and down and it should NOT turn.

Good luck!