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Big-Sert Inch Engineering Data

INSERT	DRILL		C.BORE		TAP
SIZE	DRILL	SIZE	MIN. DIA	MIN. DEPTH	MAJOR DIA.
1/4-20	7.8mm	.307	.355	.050	.359
1/4-28	L	.290	.330	.055	.330
5/16-18	13/32	.406	.474	.085	.474
5/16-24	13/32	.406	.474	.085	.474
3/8-16	31/64	.484	.552	.085	.552
3/8-24	31/64	.484	.552	.085	.552
7/16-14	37/64	.578	.634	.085	.634
7/16-20	37/64	.578	.634	.085	.634
1/2-13	41/64	.640	.701	.085	.701
1/2-20	41/64	.640	.701	.085	.701