On Jul 18, 7:57*pm, Louis Ohland wrote:
* I bought some TPMB-322 HSS inserts from Little Machine Shop for use on
some 1/2" shank toolholders.

AR Warner uses .125 screws (4-40).

Actually, .125 screws would be 5-40 (yes,
it IS standard, just not terribly common).
4-40 might fit, loosely, but wouldn't be the
first choice.