A 1x2x3" Block Calibration Cube

A 1x2x3" block, because why not. I thought it might be a good calibration cube for people that have a precision ground 1x2x3 block. It has 3/8" holes and 5 are threaded with 3/8-16 UNC threads. Update: I modified the threads as I forgot to in include a tolerance, a 3/8 bolt should now fit, and I added a 1x1x1 block just because. The 1x1x1 has X, Y, and Z markers, just for easier identification when using it to calibrate.