When I move it from 0 to 1000 it moves 2mm to much.
Moving it back to 0 it only moves 998mm.
I could repeat the same 3 more times, moving positive 2mm to much moving negative moved 2mm to little…
Moved with G1 from the terminal…
I marked my axis, motor and wheel moves with no slip. Have not noticed any tooth skipping under the movement. I can’t move the about by hand, there is no slack…
Any ideas?
Check all your grub screws. This is a common issue with loose grub screws. See if that helps, we can continue to troubleshoot from there.
I made a mark going across the motor axis and the GT wheel observed it closely while moving, no slack there…
Will check the screws , but don’t think they are loose…
If it is actually 2mm off EVERY time then I would think its electrical/software related rather than mechanical/grub screws. Unless the grub screws slip the exact same amount each time, which I suppose is possible.
It doesn’t hurt to check the grub screws though! But my unprofessional opinion is its not a mechanical issue.
It sounds like it is slack or backlash. I was sure it was going to be the grub screws, but the marker trick is hard to beat.
What happens when you move back and forth 100mm? Is it still 2mm or is it 0.2mm?
If you energize the motors, and nudge it with your finger, what moves?
I will try the 100mm when I get home…
I can’t find slack anywhere, when energised it’s rock solid, moves 1/10mm or less…
Will also try moving it from the move menu, have som funky issues with my z axis with G1 commands, but from the move menu no problems…
Is it speed related? The max speed in our firmware defaults to 5mm/s for Z. If you have changed that, or you have 1 start leadscrews, that might cause some skipped steps.
The job menu should be doing almost exactly the same thing as a G1, except the speed may be different.
The F parameter on G1 is in mm/min, so F300 is 5mm/s F60 is 1mm/sec.
I think I had a loose connection on my endestop, I changed it and no more Z axis probs…
Ok, tried some more movement, I don’t observe the problem at 100mm movement, think it is to little…
Moved to 1000mm and back a bunch of time
It slips 1 to 2mm each time against higher X value. Did not have more time.
This makes no sense.
What board, and drivers are you using, how is it wired up. How fast are you trying to move?
Skr 1.4 turbo, tmc2209, expertsnoobs dual endstop firmware, have not changed much…
Fan0 to neopixel pin…m
Maybe some stepper settings, come to think of it, I am at 72 steps pr mm, might that be my problem? That’s what I calibrated to for getting the right movement…
G91
G92 X0 Y0 Z0
G0 Y1000 F1200
G0 Y-1000 F1200
G0 Y1000 F1200
G0 Y-1000 F1200
G0 Y1000 F1200
G0 Y-1000 F1200
G0 Y1000 F1200
G0 Y-1000 F1200
G0 Y1000 F1200
G0 Y-1000 F1200
Measure to make sure that it actually moves 1000mm, 72steps/mm is not correct. Also since it is not my firmware what is the current set at and what steppers are you using? Is That firmware set for 2209’s or 2208’s?
I expect my gcode above to work as expected. The rest is only if that is not working.
how many teeth does you pulley have ?
and how many micro steps per revolution on your steppers ?
For my setup pulley 20 teeth, steppers 200 micro-steps my settings is 80 steps per mm
For recommanded V1 setup its 16 teeth pulley(same 200 micro-steps steppesr if i’m right) and it must be configured at 100 steps per mm
For complete formula read that post :
Maybe your belt is broken or stretched? You don’t have the white steel core belts do you? Those work harden and break.
That doesn’t quite explain the backlash though.
It dos move 1000mm positive, 998-999mm negative…
Firmware: https://github.com/TheExpertNoob/Marlin-LowRider2-BTT-1.4
Current is set to 800mA
microsteps: 16
I found something that looks odd, “Default axis steps per unit” is set to 143 for X and Y, and 800 for Z. For Y i have similar step pr mm of 72 to get thing right…
As far as i can tell (noob) the firmware is set to TMC2209 driver. All the defined drivers in config.h says TMC2209, not sure where else to look?
My steppers are Nema 17 Bipolar 1.8deg 65Ncm from Stepperonline.
I will check my belt thoroughly and the wheels…
You used my gcode with the slower speeds?
There is no firmware way for it to move differently. So the options are, moving so fast you skip a step at the turn around do to extremely poor accelerations, loose grub screws, broken belt.
I have not checked that firmware but 143 steps per mm makes no sense to me. 2mm belt, 16T pulleys, 200step/rev steppers, 16or 32 micro stepping. You should be at 100, 200, or 400. Our SKR Pro with 2209 uses 100x, 100Y, 400Z.
I just checked, that firmware is set at 200,200,800. What size pulley do you have that you changed it to 143?
That firmware is also set to 800 and 900 for current. I think you have something fishy with your firmware, you might want to start fresh.
I have no idea why it is set to 143 in my version…
I think you are right about starting over, i was clueless when i started fidling around with that firmware…Not that i have become an expert since but not as clueless 
