I have had my Altmill for about 9 months and everything was fine until I noticed that the left and right sides were not moving together. I found and tightened loose connections on the right end of the Gantry. After that I noticed that when I run the unit all the way forward the right side is off the stop by 1/8 to a 1/4”. I have been running it this way for three or four months and haven’t had any major issues. Until now I noticed that the motor coupler on the right side has opened and the coupler is rubbing on the motor face or frame. See the metal shavings on the ground below the coupler. The two sides are not running together again. So I loosened the set
screws in the coupler, closed the gap and retightened it. This only stays closed for a few minutes and the coupler separates again. Why is the coupler slipping on the shaft. Do I need a new coupler or motor and coupler? Please help, I have my first big job and I need my machine running. Thanks K2
You say the right side is off by 1/8 to 1/4” from the stop - the stop exists as a last resort and should never be touched (after thought - I am assuming you are talking about the carriage stops and not the coupler components)
Looking at the amount of metal shavings, you have a destroyed coupler, destroyed motor shaft or both. You need to take it apart and see what the situation is. You might be lucky and what you see is shavings from the coupler running against the motor housing or mounting bracket and the actual shaft and inside of the coupling is still fine.
It is a good idea to use loctight on these critical screws but you could have a situation where the coupler is a tad too large and, as a result, it can’t grip the motor shaft tight enough. Again, you need to check the motor shaft and the inside bore of the slipping coupler.
For future reference that could have been corrected by turning the ball screw by hand and verified with gSender’s XY squaring tool. If the X is perpendicular to the Y when both sides hit the stop then it is out of square when one side isn’t. This turns squares in parallelograms, circles into ovals, as well as adding stress to mechanical parts.
I can’t say for sure that running it out of square contributed to your current problem but it certainly didn’t help.
Good luck, hopefully it doesn’t cost too much to fix.
