Z depth issue

I’ve been working on a salt and pepper grinder holder and set have estlcam set to make 3 cuts at 15.9mm deep. The first is a pocket with a straight 1/8 end mill the second is a finishing pass with a with a 1/8" round over bit to filet the inside corners where the bottom meets the walls, the third is a parting cut with the 1/8" bit again. The problem is the first pocket went down 4mm deeper than the other three cuts, I checked my estlcam setup, and my gcode output file, all show the final depth at 15.9mm… super odd, any one have any ideas what could be causing this? I should also note I am using a peeling cut for the pocket.


Did you properly zero the Z-axis before each pass? If you change out the bits, it is almost impossible to get the end of the bit at the exact same position each time, so you’ll need to zero the axis after changing the bits to make sure the machine knows where the end of the bit is starting.

Thanks for the response,

Yes I have the program start with zeroing out the xyz, then when I change to the rounded bit it zeros all three axis again, and once more when I go back to the flat bit.

The problem is the first operation, its gone down 4mm of that it should have.

I"m having, I think, a similar issue with Z depth.
I hope I’m not hijacking this post. but adding to it as it seems similar.

I"m prepping foam for cutting a wing part. I faced one side and flipped it to face the other. My final thickness should have been 1", but am around 3/4". not sure what happened.

I did zero out the Z axis after i flipped the part.

any ideas where to start trouble shooting?

Edit - thinking of it more, I think my issue is more about creating a precision stock part from an un-precise starting chunk of foam. Maybe I will start a separate thread on this.

As a guess, I’ll bet you are taking your home Z position from the top of the stock and its height off the spoil board does not match the one you have in your authoring software. And this kind of error can be doubled when doing two-sided milling. As a start, home your bits against the spoil board, move up the thickness you have for your stock in your authoring program, then zero your Z again. This will assure that your Z height off the spoil board matches what you have authored.

@robertbu this sounds about right,
I"m going to move this over to my other thread where we have been discussing things.
I feel like this would hijack this original post and i don’t want to do that since the z Axis issue is different.

here’s the post link if others want to follow

I’ll respond there shortly.