I built two carbide cutter tools a while back. Both use a half inch carbide cutter. The difference is that one tool uses a 3/8” round rod and the other uses a 3/8” square rod. Both tools have about 10” of steel sticking out of the handle and about 4” in the handle.
The square rod cannot touch the wood without catching, but the round rod can cut the same area fairly easily. My initial thoughts were that the round rod is able to flex a little allowing some forgiveness.
Does anyone else have a theory about this?