Bit gauging into wood

I just got my Shapeoko a month ago and having issues. Yesterday the bit gouged into the wood after running for 45 minutes. Now today I load up a file and the bit gouged right away.
I have a Pro XXL with Bitsetter and BitZero.
This is the sequence of the operation.
Mount wood
Initialized the machine.
Router goes to the back of machine
Comes to the front center
Changed to BitZero Pin
Router runs over to Bitsetter
Comes back to front center
Manually move over to BitZero using CM
Set XYZ zero
Load Job
Hit start
Router moves to front center
CM asks to change bit to the correct one for the job.
After change the router goes over to the Bitsetter and measures
Start router
Machine gouges about 1/8" into board

I read where a couple other people was having the same issue but didn’t see the fix.
I only change the bit when CM ask for it.


Hi @David6ft6,

  • can you upload your gcode file for a look ? (and a picture of the piece as it is right now, if you can ?)
  • Can you confirm that the Z axis does not max out upon initial retraction after starting the job ?
  • did you have a chance to visually double-check Z zero after using the BitZero?
  • After the gouge happened and you stopped the job, did you verify where Z zero was then, with respect to stock surface ?
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I ran the job again but this time after I used the BitZero, I manually set the Z and the file ran just fine. I started another smaller job the same way and during the second pass it gradually with deeper and deeper.

Log File
cnc log.pdf (205.7 KB)

Is this a slot just as narrow as the endmill? If so, add geometry and cut as a pocket down to tab depth or the penultimate pass.

Is the endmill pulling out of the collet? (measure endmill stickout before the cut and verify it after)

This is a contour cut. Plug this the third different file that this happen to.

You should add geometry so that you are not cutting a slot — where possible avoid slotting and add geometry and cut as a pocket


and consider leaving a roughing clearance and taking a finishing pass.

This one is not a narrow slot and it still dug deep into the wood. It does explain why the bit decides the dig into the wood.

Is the endmill pulling out?

Is the working area not in the same plane as the gantry?

If it’s not either of those, please take photos of your Z-axis motor wiring and and connectors, including the controller w/ close ups of the logos on the housings and send those in to