3 Tap Drilling Sizes

Drilled Hole Size

Metric Wire Insert Screw Threads		UNC Wire Insert Screw Threads		UNF Wire Insert Screw Threads		BSW Wire Insert Screw Threads
Thread Size	Drill Dia. MM	Thread Size	Drill Dia. MM	Thread Size	Drill Dia. MM	Thread Size	Drill Dia. MM
M2X0.4	2.12	No2X56	2.3	No2X64	2.29	1/8X40	3.34
M2.5X0.45	2.63	3X48	2.65	3X56	2.63	3/16X24	5.03
M3X0.5	3.15	4X40	3.01	4X48	2.98	1/4X20	6.6
M3.5X0.6	3.68	5X40	3.34	5X44	3.32	5/16X18	8.3
M4X0.7	4.21	6X32	3.71	6X40	3.67	3/8X16	9.3
M4.5X0.75	4.72	8X32	4.37	8X36	4.35	7/16X14	11.5
M5X0.8	5.24	10X24	5.1	10X32	5.03	1/2X12	13.2
M6X1.0	6.3	12X24	5.76	1/4X28	6.5	9/16X12	14.8
M7X1.0	7.3	1/4X20	6.6	5/16X18	8.2	5/8X11	17.1
M8X1.25	8.4	5/16X18	8.3	3/8X24	9.8	11/16X11	18
M9X1.25	9.4	3/8X16	9.9	7/16X20	11.4	3/4X10	19.7
M10X1.5	10.4	7/16X14	11.5	1/2X20	13	7/8X9	22.9
M11X1.5	11.4	1/2X13	13.2	9/16X18	14.65	1”X8	26.2
M12X1.75	12.5	9/16X12	14.4	5/8X18	16.2	1.1/8X7	29.5
M14X2.0	14.6	5/8X11	16.4	3/4X16	19.4	1.1/4X7	32.6
M16X2.0	16.6	3/4X10	19.7	7/8X14	22.7	1.1/2X6	39.1
M18X2.5	18.7	7/8X9	22.9	1”X12	25.9
M20X2.5	20.7	1”X8	26.2	1.1/8X12	29.1
M22X2.5	22.7	1.1/8X7	29.5	1.1/4X12	32.3
M24X3.0	24.9	1.1/4X7	32.6	1.3/8X12	35.4
M27X3.0	27.9	1.3/8X6	36	1.1/2X12	38.65
M30X3.5	31	1.1/2X6	39.2
M33X3.5	34
M36X4.0	37.2
M39X4.0	40.2

BSF Wire Insert Screw Threads		G(BSP) Wire Insert Screw Threads		BA Wire Insert Screw Threads
Thread Size	Drill Dia. MM	Thread Size	Drill Dia. MM	Thread Size	Drill Dia. MM
3/16X32	4.97	G1/8X28	9.9	0	6.4
7/32X28	5.97	1/4X19	13.5	1	5.6
1/4X26	6.6	3/8X19	17	2	5
9/32X26	7.3	1/2X14	21.4	3	4.4
5/16X22	8.2	5/8X14	23.3	4	3.8
3/8X20	9.8	3/4X14	26.9	5	3.4
7/16X18	11.4	7/8X14	30.6	6	3
1/2X16	13.1	1”X11	33.8
9/16X16	14.6	1.1/8X11	38.4
5/8X14	16.3	1.1/4X11	42.5
11/16X14	17.9	1.1/2X11	48.3
3/4X12	19.5	2”X11	60.2
13/16X12	21.1
7/8X11	22.8
1”X10	26
1.1/8X9	29.3
1.1/4X9	32.4
1.3/8X8	35.7
1.1/2X8	38.9

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