It is a bad idea to use the bit shank as a guide. This generates a tremendous amount of heat which kills HSS bits almost instantly and can weaken the braze that holds the carbide on that type of bit. The material that was riding on it would most likely burn before that happened. The bearing I showed earlier fits on the shank and spins freely without generating the heat.
The Whiteside bit I used when I made the work station inserts for my router table has a bearing on both ends so it can be used above or below. In the first two photos you can see the safety starting pin. This is the way to get a finish cut like you see in the third photo. Note this is 50+ year old used plywood!
"Living in the D" (this means Detroit!)
"It's fine to disagree with other members as long as you respect their opinions"
Last edited by Mike; 07-22-2015 at 12:12 AM.