Hey, Phil?
Any particular reason the jig you show [http://www.jpthien.com/cj.htm] uses a 1/4" inside notch and a 1/2" outside notch for catching the bearing?
Why not make both notches 1/4" inch?
--Mik
Sorry for the slow response.
1/4" because you're cutting the full depth of the material, because you're going to lose your pivot point when you're done. 1/2" is more difficult to plow through material.