I’ve noticed a small, but pretty much consistent error when using my Bitzero in the Z axis only. Regardless of whether I’m probing on a corner or using Z only probing the result always is about .2mm higher on average than it should be compared to lowering the bit over a piece of paper in .025mm increments until I feel resistance to lateral movement. In freedom units that’s about 8 thousands which is more error than it seems it should have.
My questions are is this typical of what others are seeing, or is there a way to calibrate the device, or do I just have a bad Bitzero?
I have a v1 BitSetter but the V2 is similar in that there are two sides and two sides have a gap. I hold my V1 down when doing Z only because it tends to rock. You could set X and Y with a V2 and then use the paper method to set Z. I buy 24lb bond paper for my printer and scrap paper gets cut into 1" x 4" lengths to use for setting manually. I wiggle the paper back and forth while jogging the Z down and when the paper quits moving I am set. So then I set Z zero. It could just be the BitSetter is slightly up and as soon as the bit is grounded it sets Z Zero so try holding the BitSetter in place or use the paper method.
Another issue could be if you use painters tape and super glue to hold your project down. If you measure the wood without the tape on and then secure it down the masking tape that may be where your error is coming from. If that is the case measure once you get the project secured.
Another method would be to use the spoilboard as your Z zero and in CC set Z Zero to bottom. If you set bottom as Z Zero then the height is not as important because the first cut will start a little deeper but you finish up at the spoilboard. However measuring stock height with tape is still important because very small bits like 1/32" can break if you take too heavy of a first cut.