There's something wrong with my X axis

My machine was running quite accurately, but it recently began losing its precision. Presently, the width of rectangular parts is approximately 0.08 inches larger than intended, while the height (y-axis) remains consistent. This discrepancy leads me to suspect an issue with the x-axis.

I’ve checked the squareness of the gantry and tramming, and they appear to be in proper alignment. Interestingly, when I conduct test cuts on a soft foam board, the dimensions are accurate and there are no discernible issues. However, when I replicate the same test cuts on a denser material like pine board, the circles turn out irregular, the rectangles are oversized, and the corners appear curved.

I’ve attached a picture showcasing these test cuts. Could anyone offer insights or assistance in resolving this issue?

Is the result the same if you run at 50% feed rate?

And I noticed your corners are very not-square; is that intentional?

No, it is not intentional. I was trying to cut rectangles with right angles. :smiling_face_with_tear:

Smells like a rigidity problem, then. Check that the springs on the drive pinions are properly tensioned (and actually working - sometimes they stick). Check torque on all your fasteners, especially on the bearings. Check that the pinion gears aren’t worn.

Or just grab the spindle and try to wiggle it and see where it gives…

Check the motor setup in Mach4 to ensure you have the motor acceleration set correctly. I think the Avid default value is 50.

If it was running fine before, and all of a sudden started doing this, I’d guess something came loose (really loose). This is pretty gross for a software setting, especially if it was working fine before. Something in your drive gear assembly. Check the drive pulley screws, and everything else.

Ah-ha! My spindle is loose! This would account for the curved corners and the increased width.

Thank you, everyone, for your contributions. It appears to be a rigidity issue—something has come loose, specifically the spindle. Now that the problem’s source has been identified, I’m eagerly looking forward to heading to the workshop tomorrow to tighten things up. I’ll provide an update to let you know if the solution works. :grinning: