Part of the reason for this tap drill chart page is to make it handier for me to find. I'm going to, over time, put as many charts and tables on the internet as I can. At least the ones I use. Then when I need to look up something in one of the tables or charts that I know exist, I just go online and to my Chilipepper web site and presto! The data I need is readily at hand. I hope this chart proves useful to you as well.

Tap Drill Chart. Sizes for threads of American National Form
Screw Thread		Commercial Tap Drill
Outside Dia, Pitch	Root Diameter	Size or Number	Decimal Equiv.
1/16 - 64	.0422	3/64	.0469
72	.0445	3/64	.0469
5/64 - 60	.0563	1/16	.0625
72	.0601	52	.0635
3/32 - 48	.0667	49	.0730
50	.0678	49	.0730
7/64 - 48	.0823	43	.0890
1/8 - 32	.0844	3/32	.0937
40	.0925	38	.1015
9/64 - 40	.1081	32	.1160
5/32 - 32	.1157	1/8	.1250
36	.1202	30	.1285
11/64 - 32	.1313	9/64	.1406
3/16 - 24	.1334	26	.1470
32	.1467	22	.1570
13/64 - 24	.1490	20	.1610
7/32 - 24	.1646	16	.1770
32	.1782	12	.1890
15/64 - 24	.1806	10	.1935
1/4 - 20	.1850	7	.2010
24	.1959	4	.2090
27	.2019	3	.2130
28	.2036	3	.2130
32	.2094	7/32	.2187
5/16 - 18	.2403	F	.2570
20	.2476	17/64	.2656
24	.2584	I	.2720
27	.2644	J	.2770
32	.2719	9/32	.2812
3/8 - 16	.2938	5/16	.3125
20	.3100	21/64	.3281
24	.3209	Q	.3320
27	.3269	R	.3390
7/16 - 14	.3447	U	.3680
20	.3726	25/64	.3906
24	.3834	X	.3970
27	.3894	Y	.4040
1/2 - 12	.3918	27/64	.4219
13	.4001	27/64	.4219
20	.4351	29/64	.4531
24	.4459	29/64	.4531
27	.4519	15/32	.4687
9/16 - 12	.4542	31/64	.4844
18	.4903	33/64	.5156
27	.5144	17/32	.5312
5/8 - 11	.5069	17/32	.5312
12	.5168	35/64	.5469
18	.5528	37/64	.5781
27	.5769	19/32	.5937
11/16 - 11	.5694	19/32	.5937
16	.6063	5/8	.6250
3/4 - 10	.6201	21/32	.6562
12	.6418	43/64	.6719
16	.6688	11/16	.6875
27	.7019	23/32	.7187
13/16 - 10	.6826	23/32	.7187
7/8 9	.7307	49/64	.7656
12	.7668	51/64	.7969
14	.7822	13/16	.8125
18	.8028	53/64	.8281
27	.8269	27/32	.8437
15/16 - 9	.7932	53/64	.8281
1 - 8	.8376	7/8	.8750
12	.8918	59/64	.9219
14	.9072	15/16	.9375
27	.9519	3132	.9687
1 1/8 - 7	.9394	63/64	.9844
12	1.0168	1-3/64	1.0469
1 1/4 - 7	1.0644	1-7/64	1.1094
12	1.1418	1-11/64	1.1719
1 3/8 - 6	1.1585	1-7/32	1.2187
12	1.2668	1-19/64	1.2969
1 1/2 - 6	1.2835	1-11/32	1.3437
12	1.3918	1-27/64	1.4219
1 5/8 - 5 1/2	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 1/2	1.7113	1-25/32	1.7812
2 1/8 - 4 1/2	1.8363	1-29/32	1.9062
2 1/4 - 4 1/2	1.9613	2-1/32	2.0312
2 3/8 - 4	2.0502	2-1/8	2.1250
2 1/2 - 4	2.1752	2-1/4	2.2500

Chilipepper Sales 1380 Greg St., # 221 Sparks Nevada, 89431 PH (775)-359-1223

Tap Drill Chart

Tap Drill Chart. Sizes for threads of American National Form