SIZE	THREADS per INCH	TAP DRILL SIZE (mm)
1/4"	26	5.30
5/16"	26	6.90
3/8"	26	8.40
7/16"	26	10.00
1/2"	26	11.50
5/8"	26	14.70
3/4"	26	17.75
7/8"	26	21.10
1"	26	24.75