Yes I had that happen to me to Nate before I did the four linear bearing upgrade, but it wasn't the couplers that caused the problem, I was trying to level the bed. I printed this from thingiverse http://www.thingiverse.com/thing:12664 where you would run the bolts through to mount the bed, I heated the nuts that fit these bolts then melted them into the plastic, also covered the nuts with plastic, of course had the bolt in the nut. This helped greatly, so I could level the bed from the top of the bed instead of underneath like I had been doing, soooooo much easier to level the bed now. I did have to cut the glass down 3/4's of an inch so I could get to the bolts from the top of the bed to turn them, I used to work for a glass company so no problem, even had a glass cutter. On the Z axis, actually, the stepper would only move the Z axis, the bed would not move at all, the Y axis would work like an overhead crane [inside of a building] or gantry, the X and Z axis would be mounted to the Y axis, the X would move left and right and of course Z would move up and down from the gantry. This is exactly how my cnc plasma cutter is set up. I think this would work very well, be more stable, more accurate, better resolution. With two steppers on the Y it would be very strong.
Cool, so the Z axis would lower the bed like the RepRap Orca?Yes, eventually I want to build a printer out of aluminum, all parts cast. I'm also going to make the heated bed stationary, have two steppers move the Y axis and one move the Z axis.Ohh cool.. is that for casting metals?Yes, the X ends are for another printer I want to build, want to try wax extrusion.Are you printing a set of X ends for spares?
I just battled with my first prusa tonight. I had a Z motor coupler break, so I had replaced them with the newer print design. Well stuff started printing uneven. So while messing with it I found out the couplers were slipping, then they fell.:@ Then getting the Z and bed all matched up again.. what a pain. I can't wait to redo this printer, or better yet use my new printer! lol Z home position is the worst thing to set up on my printer. I need those adjustable magnetic endstops soon!
I'm printing the latest of my RAMPS box now. I'll try to get files out tonight for it.