Right side of y-axis 'slippy'

Something appears to be wrong with my x-carve calibration. I seem to have a very slippy right side motor on the y-axis of my 1000 x 1000 x-carve. I’m constantly needing to adjust it to bring it back to square with the other side.

For example, if I hand adjust the y-axis, the left side motor will move uniformly, predictably. The right side however moves like a rubber band - for every mm the left side moves, the right side might boing 20 to 40mm - not at all in unison with the movement occurring on the other side.

Any suggestions for a fix?

Check your wiring, sounds like the right motor isn’t connected properly, check at both sides of the gantry.

FYI - I’m not in the habit of hand moving the x/y axis (axes?) around the cutting footprint - I only do so to square up the axis as necessary.

I have 2 blocks that i place between the x-axis makerslide and the front riser plates when I power up the machine, this ensures I have square. Once powered you shouldn’t get out of square unless you have some other wiring or electrical problem with the controller or motor.

I don’t think it’s an electrical fault. If it were an electrical fault it would manifest randomly and I wouldn’t be able to cut anything neatly, predictably - especially complicated designs. Here’s my current project - a TV cabinet - 24mm deep panels - the x-carve cut 15 passes over the same path of each panel without an increment of tracking error.

I made the mistake of cutting the end panels without checking calibration, and they proved to run a little diamond shaped rather than square. All faults hidden via a liberal dashing of TimberMate.

Here’s the crux - If I recalibrate the y-axis before commencing a cut the accuracy is no problemo. But I don’t understand why I need to recalibrate the y-axis prior to every piece?

Edit - I just see your latest reply. Perhaps it is an issue caused by machine power up/down. Regardless, the right side of the y-axis seems much more slippy in movement than the left side… is that normal?

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When you say slippy, do you mean only when not powered? Are your left and right belt tensions the same as each other?

The squareness is a known issue although I couldn’t quickly find any inventables instructions for the issue there have been many posts on the forum.


When I say slippy, that means any time I need to calibrate this axis by hand - push the gantry 1mm, slowly, softly, and the left side y-axis moves 1mm, but the right side axis will bounce ahead at least 20 or 30mm. It seems I need to calibrate this axis every time I use the machine. I figure it has something to do with this bouncy behaviour.

As you suggest earlier - I now use a spacer against the y-axis uprights to confirm calibration, brought about from this latest project hiccup.

Belt tensions appear to be the same as each other, although I have no means to confirm this beyond eye-balling.

My calibration test is to cut an engraved dot at each corner of a 700mm square, then measure diagonally for discrepancy.

I have never seen or read anything about the bouncy behaviour but a short video demonstration would be great.

Can do. Although i’m in Australia, and it’s too late/dark in my cave to shoot a clear video right now. I can make a short video tomorrow during the day time no problemo.

Can I upload videos directly here? Or do I need to link via Youtube?

YouTube works best.

Check your grbl parameter settings. Specifically make sure the $1 parameter is set to 255 ($1=255).
Use “machine inspector -> advanced”.

If you have the X-controller check to make sure that the torque reduction feature is turned off. (DIP switch 4 OFF, in the picture DIP switch 4 is in the ON position).

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LarryM, you are my hero. This has transformed my machine. I could not keep the gantry square to save my life. It looks like the DIP switch change and spacers to set it before powering up did it.