Reply by AandCstyle

Shelly, I believe the Byrd heads have the cutters are patented and they are perpendicular to the curve as can been seen here. The Grizzly and others have the cutter set perpendicular to the cylinder as shown here. I am not aware of any head to head studies that have found the Byrd heads to be significantly better, but there may be some out there. Practically speaking, I doubt there is much of a real world difference, but I could be wrong with regards to really wild grained wood.

I fix mis-aligned joints with my ROS. FWIW

-- Art