Ok sound and dropping z or not lifting z back on max side the closer I get to that side. It can mess a job up. I set running and home amps to .95. Not sure if that’s why it’s a bit better now. Tried lower like Doug and she wouldn’t lift. Video from my YouTube channel to show it in action. Skipping or not enough power?
LR4 Z max noise
0:09 sound like motor skipping steps to me.
Did you lube that lower portion of the leadscrews really well? Make sure temp stickers are adhered to Steppers first before lubing anything.
Something that previously help me fix Z axis leadscrew binding :
Good luck!
Aza B2C you are a life saver. I never tighten those past just lightly in the nylock. Damnit. It’s fixed and running smooth now to dial down amps again. Thank you all!!
Cool, happy cutting!
Did loosen the nylock help, or, did you recenter the leadscrew, or, did tightening nylock help? This last one, fixing by “tightening nylock” would surprise me, usually 've seen people removing the nylock helps them reduce binding between Z Stub and Z Nut. Z Stub and Z Nut layer lines are the same orientation, so there’s a chance they can bind, sanding/lubing faces where those parts touch can help?
Sorry if you explained already, am trying to understand what held you back, root cause, and what helped you? Am hoping to learn info that helps future folks based on yours and others’ experiences. Cheers!
Looks like you have a nice big 4’ usable X. If you’re considering keeping your steppers at 0.9 or 0.95A, to avoid drivers overheating/cutting-out, ensure your enclosed stepper drivers have the heatsinks stuck on, and are ventilated (e.g. got a fan on the controller box)… Personally, I like the thermal stickers like the one’s Ryan sells too to help make sure I’m not melting the PLA, if/when I set current too high 
I ended up setting the lead screw center and tightening the screw in the nylock. Adjusted a few times at mid height till it was happily gliding. Before I did that the lead screw was going all over so yes great solution. And now there’s tons of line as well.
Question: does the system switch to hold amps when that axis stops during the run as the other motors are moving?
I read about keeping those values the same so during a cut it wont lose steps as easy on the waiting motor, but it may not have relevance with fluidnc. Perhaps something to verify. Though it may have been more for going from 0.9 to 0.5 vs 0.68 to 0.5.
I’m definitely not an expert on FluidNC. I know only the vagueness implied by “hold” and “run” and that there is a need for balancing both the motor applied strength and its tendency to built up heat.