# Depth problem

Hi guys. On my machine on both acme shaft and 8 mm threaded rod, when cutting depth, if I say 4mm, it cuts appr 1 mm. Any suggestions please?
Otherwise I’m working very well with the machine.

First, how are you setting you 0 point for the z axis?

Assuming that isn’t the issue, it’s likely your Z motor steps. Have you calibrated your steps per mm? Lots of resources here if you search for step calibration.

You may have to change the \$102 setting. My acme rod was determine to be 188.976 I believe.

If it’s the Inventables M8 threaded rod then \$102 = 320.00 and then you calibrate from that starting point.

Thank you a lot, I will try that and give feedback on results.

@DanielBoshoff If you jog your Z axis 50mm, does it actually move 50mm. If not, you’ll need to calibrate your steps. If it does, maybe it’s an issue with your zeroing.

No, if I jog it for 50 mm, it goes only 12mm

Setting is exactly \$102 = 320.000

If you are off by a factor of half, eights or double or quadruple = micro step value.
Can also be adjusted by changing the \$102 value as suggested above.

Twice the travel vs commanded travel reduce \$102 by 50% => \$102=160

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May need to check micro-stepping settings.

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Just checked and measured exactly, sets to cut 10mm and it only does 2 mm.

Thanks LarryM,

Where can I check micro-step settings please?

That will be on the stepper driver, usually by jumpers or switch position.

IIRC:

ACME is 8mm/turn
Stepper motor is 200step/revolution
8mm/200steps = 0,04mm per full step
You currently have \$102=320 => says that 320steps need to be performed to move 1mm
You command 10mm (3200steps) but only get 2mm so actually you get 1mm = 1600steps

Current step value (320) * commanded distance (10) / actual distance (2) = new value (1600)
Adjust \$102 to 1600 and try again

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Assuming you have the X-controller, check these jumpers on the internal board.

Thank you allll !!! including google and youtube. I got my problem solved.
I changed the settings on \$102 to 1600, and my machine is running perfect now.

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If you are running \$102=1600 your microstep setting is high. Torque will be less at higher micro step levels.

I would suggest you change to half or quarter step (1/2 or 1/4 step) and adjust \$102 accordingly.
Ideally you would run full step but real world use micro step level to smooth out the machine.

Full step resolution is 0.04mm so from a accuracy point of view micro steps are not required, only increase microstep level to make machine run smooth Especially noticable during acceleration/retardation.

Stepper step precision is the greatest at full step (usually +/-5%) but incremental step may easily be off by +/-20% and dont offer much for our kind of machines.