z axis not going up or down like this when I arrived @dannym @jamesfreeman
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Try opening the front door and then raise the table all the way up. Then close door. A few times in the past people have lowered the table past a lip on the front door and when raising it back up the table shifted getting jammed into that lip.
fixed. the drive pulley was slipping, in part because the bed was loaded with the max size of 3/4 plywood so like 50 lbs. that’s probably the max ever put on the bed. the bed doesn’t have a rated weight limit, it should be able to do this, but the z leadscrew doesn’t have a flat for a set screw to grab.
it may sound simple to just grind a flat into that but this would require first disassembling the chain drive which would be really problematic to take apart and get back together. it was done as a chain drive because closed loop belts aren’t made in the length needed, and the path around the 4 leadscrews could not be done with a single closed belt since it would have to pass through 4 slots in the frame. with a closed belt that’s impossible.
it’s tighten back down and ok for now. I’m looking at a better way to rebuild this that would also keep the bed from twisting, and i think i see a good way to do this now. i have a ballscrew conversion kit on hand but that was going to be really difficult to use with the chain drive and 1.6m bed width. but i see how this can work. once again 3d printing may save the day. I’m working through the plan really carefully because once i take apart anything on that chain drive I can’t restore it again. it has to be guaranteed to work on the first try.
The guy using it (didnt have a slot reserved) when I arrived last night for my reservation was cutting 3/4’ ply so that makes sense that he lowered it so much.
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I assume the set screw isn’t digging in because the shaft is hardened? Instead of grinding a flat, would it help to use something like a mini diamond burr that can reach inside the screw hole to make a dimple for a pointed set screw?
