Posted by Drew on March 02, 2017 at 11:55:38:
In Reply to: Fellows 20-4 cutter offset posted by Ben on February 17, 2017 at 17:40:46:
I don't have a Fellows 20-4 or a 10-4, but I do have the manual for a 10-4. It has the formula for the setting as:
Center Distance Internal = (Pitch Dia Gear - Pitch Dia Cutter) / 2
Cutter Offset = Center Distance * Sine of Back-off Angle (REF. Sine 5 degree = .08715)
The manual says a 5 degree angle is generally used.
Again, I do not have the machines and do not know for certain if this formula is correct for your machine.