Thanks Will. I checked the pulley set screws. They were tight and one was set on the flat so that’s not moving. I’ve tried different combinations with the spring with no change. I even block up the material so the z-axis didn’t have to go so low. The thing is if something is slipping I would think that the zero would change but it doesn’t. I’ve had stepping slip happen before and the machine makes a real specific sound.
I get the same thing with a brand new amana bit with a shallow DOC.