I have an older incra ls First time trying box joints they are to snug. I was using a Irwin carbide 1/2 inch bit. I checked the bit and it varies from .510 near the Shank to .485 at the tip. I am trying to cut 1/2 inch box joints. My setup may be sloppy I will set it back up again tomorrow. Tired of messing with it today. Any ideas greatly appreciated.