<html> Hi David,                This is why I preach arcing the tails after they are glued on the shank. That way you get a nice 2 1/2" radius and the arc is always square to the hammer rail.   This paramount for high secure checking, and good repition. Regards Roger  the radius on the tail should not affect the inside edge of the tail for lining up against the rail of the jig, unless you are taking too much material off and actually shortening the hammer tail. <blockquote type=cite class=cite cite>David Koelzer Vintage Pianos DFW </blockquote> </html>