First pass is cutting 2x DoC

I am cutting material that is 0.21" with a 1/16" bit. My DoC is set to 0.03" so simple math says 7 passes. It does indeed cut 7 passes, however the 7th pass is fully in my spoil board. I measured the first pass and determined that it is cutting 0.06" On this project, this isn’t a huge deal, but I am concerned that on a project with a larger bit and thus a greater DoC this could be a major issue.

I am using the Z-Probe, measured with calipers and input to the machine manager.

The odd part to me is that it is calculating the correct number of passes and subsequent passes are the correct depth…it’s just that first cut.

Hopefully someone can help me get this straightened out.

When you set it up did you set for acme or 8mm rod.
You set $102= ?

I think Acme

I checked $102 but when I measured it for calibration it moved the distance specified so there was no change.

Now, I just ran a similar project and it cut just as it should, but the 2 prior cut as above. Baffled.

Make sure your pully is tite, no play in the acne rod. Ie movement up and down