Tap Drill Sizes

Tap Drill Size Chart

Size	Thread	Root	Drill Size	Decimal
1/16	64	0.0422	3/64	0.0469
1/16	72	0.0445	3/64	0.0469
5/64	60	0.0563	1/16	0.0625
5/64	72	0.0601	52	0.0635
3/32	48	0.0667	49	0.0730
3/32	50	0.0678	49	0.0730
7/64	48	0.0823	43	0.0890
1/8	32	0.0844	3/32	0.0937
1/8	40	0.0925	38	0.1015
9/64	40	0.1081	32	0.1160
5/32	32	0.1157	1/8	0.1250
5/32	36	0.1202	30	0.1285
11/64	32	0.1313	9/64	0.1406
3/16	24	0.1334	26	0.1470
Size	Thread	Root	Drill Size	Decimal
3/16	32	0.1469	22	0.1570
13/64	24	0.1490	20	0.1610
7/32	24	0.1646	16	0.1770
7/32	32	0.1782	12	0.1890
15/64	24	0.1806	10	0.1935
1/4	20	0.1850	7	0.2010
1/4	24	0.1959	4	0.2090
1/4	27	0.2019	3	0.2130
1/4	28	0.2036	3	0.2130
1/4	32	0.2094	7/32	0.2187
5/16	18	0.2403	F	0.2570
5/16	20	0.2476	17-64	0.2656
5/16	24	0.2584	I	0.2720
5/16	27	0.2644	J	0.2770
5/16	32	0.2719	9/32	0.2812
Size	Thread	Root	Drill Size	Decimal
3/8	16	0.2938	5/16	0.3125
3/8	20	0.3100	21/64	0.3281
3/8	24	0.3209	Q	0.3320
3/8	27	0.3269	R	0.3390
7/16	14	0.3447	U	0.3680
7/16	20	0.3726	25/64	0.3906
7/16	24	0.3834	X	0.3970
7/16	27	0.3894	Y	0.4040
1/2	12	0.3918	27/64	0.4219
1/2	13	0.4001	27/64	0.4219
1/2	20	0.4351	29/64	0.4531
1/2	24	0.4459	29/64	0.4531
1/2	27	0.4519	15/32	0.4687
9/16	12	0.4542	31/64	0.4844
9/16	18	0.4903	33/64	0.5156
Size	Thread	Root	Drill Size	Decimal
9/16	27	0.5144	17/32	0.5312
5/8	11	0.5069	17/32	0.5312
5/8	12	0.5168	35/64	0.5469
5/8	18	0.5528	37/64	0.5781
5/8	27	0.5769	19/32	0.5937
11/16	11	0.5694	19/32	0.5937
11/16	16	0.6063	5/8	0.6250
3/4	10	0.6201	21/32	0.6562
3/4	12	0.6418	43/64	0.6719
3/4	16	0.6688	11/16	0.6875
3/4	27	0.7019	23/32	0.7187
13/16	10	0.6826	23/32	0.7187
7/8	9	0.7307	49/64	0.7656
7/8	12	0.7668	51/64	0.7969
Size	Thread	Root	Drill Size	Decimal
7/8	14	0.7822	13/16	0.8125
7/8	18	0.8028	53/64	0.8281
7/8	27	0.8269	27/32	0.8437
15/16	9	0.7932	53/64	0.8281
1	8	0.8376	7/8	0.8750
1	12	0.8918	59/64	0.9219
1	14	0.9072	15/16	0.9375
1	27	0.9519	31/32	0.9687
1 1/8	7	0.9394	63/64	0.9844
1 1/8	12	1.0168	1 3/64	1.0469
1 1/8	12	1.1418	1 11/64	1.1719
1 3/8	6	1.1585	1 7/32	1.2187
Size	Thread	Root	Drill Size	Decimal
1 3/8	12	1.2668	1 19/64	1.2969
1 1/2	6	1.2835	1 11/32	1.3437
1 1/2	12	1.3918	1 27/64	1.4219
1 5/8	5.5	1.3888	1 29/64	1.4531
1 3/4	5	1.4902	1 9/16	1.5625
1 7/8	5	1.6152	1 11/16	1.6875
2	4.5	1.7113	1 25/32	1.7812
2 1/8	4.5	1.8363	1 29/32	1.9062
2 1/4	4.5	1.9613	21/32	2.0312
2 3/8	4	2.0502	2 1/8	2.1250
2 1/2	4	2.1752	2 1/4	2.2500

Tap Drill Sizes for Pipe Thread

Pipe Size Drill Size - Briggs Drill Size - Whitworth

1/8 11/32 5/16

1/4 7/16 27/64

3/8 19/32 9/16

1/2 23/32 11/16

3/4 15/16 29/32

1 5/32 1 1/8

1 1/4 1 1/2 1 15/32

1 1/2 1 23/32 1 25/32

2 2 3/16 2 5/32

2 1/2 2 5/8 2 25/32

3 3 1/4 3 9/32

3 1/2 3 3/4 3 3/4

4 4 1/4 4 1/4

4 1/2 4 3/4 4 3/4

5 5 5/16 5 1/4

6 6 3/8 6 1/4