Posted by BillS on June 12, 2011 at 09:28:24:
In Reply to: Note on print? posted by Frank on June 10, 2011 at 15:59:49:
I think that the spec referred to is the radius (from gear center line) to the point where fillet (or undercut) intersects with tooth involute profile. I've known this dimension as TIF (True Involute Form), expressed as radius or diameter.
I think the designer is saying that there will be undercut (hey, it's 11T, okay?) but the TIF diameter should not exceed 2 x 0.2147 max. (It seems clearer to refer to dimensions that intersect gear center line as diameters. Arcs are clearly referred to by their radius; e.g.tip radius.) To allow TIF to expand and "eat up" more tooth profile both lessens beam strength and reduces active profile contact.
This doesn't explain your next step; i.e. how to select a cutter. You might want to talk to Scott Atkinson at Ash Gear, who has developed TIF in his
GCP gear calculation program. You can email him at scott@ashgear.com and he can
fill you in on what TIF is all about and help you select a cutter.