I noticed a problem this morning when Rapid Jogging in CM where the entire X gantry would visibly shake when traveling X+ or X- (rapid jog speed only).
I loosened my V-wheels a bit and that seemed to help the visible shake, but if I hold my hand on the Z gantry (HDZ in my case) I can feel a bit of shake/jerk/vibration/ general unevenness to the X travel motion. The issue is worse if I apply resistance as it is rapid jogging?
Belts are good, X pulley is tight.
Bent Motor Shaft? Motor itself? or just par for the course?
Does it do the same when you ask it to rapid between compass points?
I’d probably release the X belt at both ends and manually roll the HDZ up and down the X axis to see if that moves smoothly without the belt & motor. I’d also stick a dial gauge on it and check that the HDZ wasn’t deflecting any more than expected.
If it’s lump lump then it’s probably V Wheels, maybe one of them has fractured or grown a dent from being over-tensioned, could also be the bearings, maybe one ingested some crud?
When I had my V Wheels over-tight to try to get rid of spindle vibrations the machine would have a really noticeable lump lump in X for the first few minutes of operation thanks the the dents that had formed in the V Wheels whilst the machine was stationary, there’s some evidence of those here
Generally after a few minutes of moving the lumps had flattened out, it was a sign of me abusing the V Wheels though and remember that backlash goes up with V Wheel tension as the extra rolling friction has to be countered by belt extension.