I had been noticing that when I have the X gantry at the front end of the Y rails there is increased noise and a tendency for the X. Rail to jam, particularly on the right Y rail. Previously I had looked at wheel tension and the anti backlash nuts. But all seemed OK and the issue persited.
Today I determined to investigate further and hopefully fix the issue. I ran X rail all the way back, removed the laedscrew from the right side Y rail then replaced the anti baclash nut. Put it all back together but issue was still there, had the X rail at the front where it was binding and decided to remove the locnut and pull the bearing out. I noticed the bearing still on the leadscrew does not line up with the locating hole. I ran the machine with the rigt leadscrew not supported at the front, I could not get it to jam no matter how fast i ran back and forth. I looked at the left leadscrew bearing and again the screw does not line up with the bearing. The same is true at the rear bearings. Unless I am missing something either the anti backlash mounts are off or the locating holes for the bearings are drilled incorrectly. Is this a known issue or am I reading this wrong?
Could the lead screws be bent? That could cause binding if the two ends are fixed and it is moving over that area.
I guess i would wonder in what direction they are out and by how much. If when you run it with the bearing free you would notice any extreme bend in the lead screw. Up an down adjustment, if small enough, can be made with the wheel tension and backlash nuts, more so with the backlash nuts.
When I completed my assembly my screws were binding at the end of the axes. I losened the mounting screwes for the backlash nuts and ran it back and forth a few inches. I returned it to the end of the axes and tightened the mounting screws there. They run smoothly through their entire length of travel now.
The ends are where they have the least amount of flexibility so it makes sense to tighten the backlash nuts when the axes are there.
Thanks drrk But the screws are not bent, certainly as far as I can see by rolling them on a flat surface. Jim@cncjim I do not recall the original assembly of the backlash nuts but I probably had the X rail in the middle of the Y threaded the rod by hand and then used a drill to send it all the way back. I have only eyballed how far out the screw is to the hole and I estimate maybe 3/32 max lower than it needs to be. I had already decided that I would ream out the backlash mounting holes later today but I will try your suggestion first, thanks.
So I ran out there while I was waiting for my wife to get ready and tried cncjimm idea, unfortunately it didn’t work for me so I drilled out the anti backlash nut mounting holes in the plare brought the x rail all the way forward and the laedscrew front bearing slides in nicely now. Ran front and back a few times on rapid speed without issue so I think it is fixed.