Inventables Community Forum

Z Axis upgrade issue

So i just upgraded my Z axis with the CNC4Newbie slider. After installation I wired up a new stepper motor and checked to make sure i wired everything up correct. Thankfully everything did exactly what i wanted it to. Once i updated my GRBL setting however something is making an odd noise. I went back to my original stock GRBL setting and it went away. I’m wondering if it’s a speed difference causing the change in tone or what? Has anyone else had this issue. I’ll try to post video’s as well…

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i guess i cannot upload the video’s here so here’s a link to the google drive folder. Video’s should be labeled as which is which…

What are your old/new values for:

Have you changed the micro step values for Z stepper?

The old Value for $102=188.879 (or something very close to that) My new value for $102=50.0125. I didnt know anything about $112 or $122…

Steppers can have different harmonic resonance depending on their speed and motion. Sometimes you hit a weird frequency and it sounds like she’s going to break apart.

Adjust your micro step to 1/8 ans adjust your 102 again. It will be really smooth!

can you explain how to do this?

What kind of controller do you have?

I am using the stock X controller which was purchased in late 2019.

On the red switch block to the right (Z) change switch to ON/OFF/ON. Default is OFF/ON/OFF.
This change microstep setting from 1/2 step to 1/8.

You may need to fine-tune your $102 value (applies anyhow) to get maximum accuracy.

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Also installed cnc4newbies… 7in travel.
I made suggested changes (I think correctly)
The z travel is fine while moving manually (1" = 1") but while cutting it seems to be different going up then down. The up travels seems too much. First pass is correct depth, second barely touches wood.
Move to a new shape, just cutting air.
settings here…

  • $132=175.000
  • $131=750.000
  • $130=750.000
  • $122=100.000
  • $121=500.000
  • $120=500.000
  • $112=2000.000
  • $111=8000.000
  • $110=8000.000
  • $102=200.236
  • $101=40.000
  • $100=40.000
  • $32=0
  • $31=0
  • $30=1
  • $27=1.000
  • $26=250
  • $25=750.000
  • $24=25.000
  • $23=3
  • $22=0
  • $21=0
  • $20=0
  • $13=0
  • $12=0.002
  • $11=0.020
  • $10=115
  • $6=0
  • $5=0
  • $4=0
  • $3=4
  • $2=0
  • $1=255
  • $0=10

Figured it out, might be worth noting for others…
The settings work great. The issue was mechanical.
With the risers my regular bits are too short, so the cut (in1/2in wood) was reaching the bottom endof the z movement, so obviously it kept going up, but never got to go down. Added a 1/2 piece mdf under cut and good to go.


So happy that you have found a solution. However, we should not need to add material under our material. The Z upgrade should allow cuts from the max height to to wasteboard. This is still a problem for me, and it has not been resolved after a week of being promised a solution.

@ChristopherCook you might want to know about this issue that’s been popping up recently after performing the z upgrade and altering the grbl settings…