Why are they uneven

Y does my left y axis touch before the right. There’s about a three mm gap on the right. I tried turning the ball screw, after the machine is off and it turns but wants to return to where it started. The layout is square. I was going full speed forward when it suddenly just stopped, with a bang. I brought it forward slowly to inspect and that’s when I noticed the gap. I’m still able to use it but I have to account for angle it’s at. I’m sure I read about this problem somewhere but damned if I can remember where. As always, any help is always appreciated. Thanks

Hi Philip,
This should not be that hard to resolve.

With the CNC powered off. Disconnect the two Y axis cables and manually move both the left and right sides to get both sides touching the end stop. Then reconnect the cables and power on. Using the joy stick or the software positioning controls, jog the y away from the end a few inches and home the CNC.

When it homes it should both touch at the same time.

This is the same processes that you may have used when you installed your CNC

I hope that helps.


Hey Philip,

Did it stop in the middle of the way?

If so, it could be point 5) in this document. When the controller is powered off, can you move the Y rails freely, with no noise?

And when you move it into the three mm gap, do you feel any resistance?

It could also be possible if you get a current interruption in one Y stepper cable connector that the one Y axis moves some steps while the other not, and at a certain degree of disalignment, the machine would block. With these flimsy connectors, I always suspect an electric problem :slight_smile: See point 3) in this document.

Anyway I would first try what Mike suggested.

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When the Onefinity homes using stall homing, is it the linear bearings that hit the Y axis blocks in order to stop? If so, is it important for the linear bearings to be equally seated in the X axis blocks - i.e. projecting out the same distance? Could this ever be the cause of some misalignment noted by users?

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Thanks Mike
That did it. I thought it was going to be more difficult than that.
I appreciate your help.

Mike hit the nail on the head. It was much easier than I expected. I’m grateful
you guys are around.
Thanks, Phil