Issues with Z setting

I have had the Foreman Elite Masso CNC for a couple of years now and finally broke down and got the Revolution last week. Setup went fairly smooth but I am having an issue getting the Z setting nailed down. I am using Vcarve Pro and am using the Cylinder center axis for the Z setting and setting the origin with the built in setup touch block. For some reason, I seem to not be getting consistent zeros. I have triple checked my offsets and have the Z offset at 1.378". This appears to be very close to the center of the tail stock when I checked it. My problem is that after setting everything and running the program to round the stock or rough cut, my bit may dig in and try to cut 1/2" in single passes. I double checked my bit’s pass depth and set it shallower but didn’t seem to make a difference. I just broke a $50 bit so I am a little gun shy at this point. Anyone have suggestions?

I found that the rounding toolpath gadget in V-Carve doesn’t compensate adequately for the corners of a square stock piece.
My work around was to use the surface top rather than the center of the cylinder and cheat the top by 1/4" higher. Then run it again at the regular cylinder top surface for a second pass.
I also found the toolpath strategies in V-Carve were limited for rotary work and put a lot of side load on deep profiles.
If I was doing rotary work regularly I would switch to Deskproto.

Thanks, I’ll heed your advice