ACME lead wobble

UPDATE for the record: this is not an ACME screw!

Hive mind, I could use your eyes before I disassemble and order a part across the Atlantic. Does this look like a bent ACME lead screw or could it be something else?

This machine seems to function normally during adjustments, etc, and depth is consistent within a run. Yet it must be losing some Z, because now a 6.5mm cut per Easel only plunges to about 4mm in total. Since this is down I figured there must be some serious friction and found this wobble.

The machine’s pedigree, in case it’s interesting:

This is a 500x500 X-carve that derives from an ShapeOko 2 using the original 2015 upgrade kit. So, it’s still using a grblShield, etc. It sees very little usage, cutting soft materials.

Recently, we have upgraded to the typical DeWalt 611 setup. During this installation I noticed some very subtle resistance in the Z-axis assembly, so I checked pulleys, belt, V-wheels, etc.

Being a noob with these things, I didn’t think to roll the lead screw before reassembly. I know.

I’ve made no recent configuration or electrical changes.

Good idea … but I can pick up the entire machine using the router, and there’s no play there.

Even though this issue came with the router, I’m open to tips for validating the software path. I’m not a hardware geek, so hate taking apart things that (mostly) work!

same here. never had a problem with it.

Thanks all, I’m happy to have some encouragement to look elsewhere before replacing the screw!

While this seems unlikely since it was working with the old spindle, could you explain what you mean? I’m letting Easel configure grbl, and do have the “2x microsteps” jumper in place on my grblShield.

If you jog up or down 25mm is the movement up/down also 25mm?
Is any discrepancy consistent?

Have you properly calibrated your current (A) limit for your drivers?
Or figured out its max current limit before it go into thermal protection?

Well, that was the dumb “did you remember to plug it in” advice I needed!

After running a bunch of tests, I determined that it was functioning completely consistently, and at just less than 3/5 the intended travel.

It turns out, that’s because I have an M8 lead screw, not ACME. Over the years I forgot this so when I reconfigured in Easel…well, the rest is obvious.

Thanks to everyone for helping me on this voyage of discovery, simple though it was.