TAP	TAP DRILL	Decimal Drill Size	Theo. % of Thread	Probable Oversize	Probable Hole Size	% of THREAD
0-80	56	.0465	83	.0015	.0480	74
	3/64	.0469	81	.0015	.0480	71
1-64	54	.0550	89	.0015	.0565	81
	53	.0595	67	.0015	.0610	59
1-72	53	.0595	75	.0015	.0610	67
	1/16	.0625	58	.0015	.0640	50
2-56	51	.0670	82	.0017	.0687	74
	50	.0700	69	.0017	.0717	62
	49	.0730	56	.0017	.0747	49
2-64	50	.0700	79	.0017	.0717	70
	49	.0730	64	.0017	.0747	56
3-48	48	.0760	85	.0019	.0779	78
	5/64	.0781	77	.0019	.0800	70
	47	.0785	76	.0019	.0804	69
	46	.0810	67	.0019	.0829	60
	45	.0820	63	.0019	.0839	56
3-56	46	.0810	78	.0019	.0829	69
	45	.0820	73	.0019	.0839	65
	44	.0860	56	.0020	.0880	47
4-40	44	.0860	80	.0020	.0880	74
	43	.0890	71	.0020	.0910	65
	42	.0935	57	.0020	.0955	51
	3/32	.0938	56	.0020	.0958	50
4-48	42	.0935	68	.0020	.0955	61
	3/32	.0938	68	.0020	.0958	60
	41	.0960	59	.0020	.0980	52
5-40	40	.0980	83	.0023	.1003	76
	39	.0995	79	.0023	.1018	71
	38	.1015	72	.0023	.1038	65
	37	.1040	65	.0023	.1063	58
5-44	38	.1015	79	.0023	.1038	72
	37	.1040	71	.0023	.1063	63
	36	.1065	63	.0023	.1088	55
6-32	37	.1040	84	.0023	.1063	78
	36	.1065	78	.0023	.1088	72
	7-64	.1094	70	.0026	.1120	64
	35	.1100	69	.0026	.1126	63
	34	.1110	67	.0026	.1136	60
	33	.1130	62	.0026	.1156	55
6-40	34	.1110	83	.0026	.1136	75
	33	.1130	77	.0026	.1156	69
	32	.1160	68	.0026	.1186	60
8-32	29	.1360	69	.0029	.1389	62
	28	.1405	58	.0029	.1434	51
8-36	29	.1360	78	.0029	.1389	70
	28	.1405	68	.0029	.1434	57
	9-64	.1406	68	.0029	.1435	57
10-24	27	.1440	85	.0032	.1472	79
	26	.1470	79	.0032	.1502	74
	25	.1495	75	.0032	.1527	69
	24	.1520	70	.0032	.1552	64
	23	.1540	67	.0032	.1572	61
10-32	5/32	.1563	83	.0032	.1595	75
	22	.1570	81	.0032	.1602	73
	21	.1590	76	.0032	.1622	68
	20	.1610	71	.0032	.1642	64
	19	.1660	59	.0032	.1692	51
12-24	11/64	.1719	82	.0035	.1754	75
	17	.1730	79	.0035	.1765	73
	16	.1770	72	.0035	.1805	66
	15	.1800	67	.0035	.1835	60
	14	.1820	63	.0035	.1855	56
12-28	16	.1770	84	.0035	.1805	77
	15	.1800	78	.0035	.1835	70
	14	.1820	73	.0035	.1855	66
	13	.1850	67	.0035	.1885	59
	3/16	.1875	61	.0035	.1910	54
1/4-20	9	.1960	83	.0038	.1998	77
	8	.1990	79	.0038	.2028	73
	7	.2010	75	.0038	.2048	70
	13/64	.2013	72	.0038	.2069	66
	6	.2040	71	.0038	.2078	65
	5	.2055	69	.0038	.2093	63
	4	.2090	63	.0038	.2128	57
1/4-28	3	.2130	80	.0038	.2168	72
	7/32	.2188	67	.0038	.2226	59
	2	.2210	63	.0038	.2248	55
5/16-18	F	.2570	77	.0038	.2608	72
	G	.2610	71	.0041	.2651	66
	17/64	.2656	65	.0041	.2697	59
	H	.2660	64	.0041	.2701	59
5/16-24	H	.2660	86	.0041	.2701	78
	I	.2720	75	.0041	.2761	67
	J	.2770	66	.0041	.2811	58
3/8-16	5/16	.3125	77	.0044	.3169	72
	O	.3160	73	.0044	.3204	68
	P	.323	64	.0044	.3274	59
3/8-24	21/64	.3281	87	.0044	.3325	79
	Q	.3320	79	.0044	.3364	71
	R	.3390	67	.0044	.3434	58
7/16-14	T	.3580	86	.0046	.3626	81
	23/64	.3594	84	.0046	.3640	79
	U	.3680	75	.0046	.3726	70
	3/8	.3750	67	.0046	.3796	62
	V	.3770	65	.0046	.3816	60
7/16-20	W	.3860	79	.0046	.3906	72
	25/64	.3906	72	.0046	.3952	65
	X	.3970	62	.0046	.4016	55
1/2-13	27/64	.4219	78	.0047	.4266	73
	7/16	.4375	63	.0047	.4422	58
1/2-20	29/64	.4531	72	.0047	.4578	65
9/16-12	15/32	.4688	87	.0048	.4736	82
	31/64	.4844	72	.0048	.4892	68
9/16-18	1/2	.500	87	.0048	.5048	80
	33/64	.5156	65	.0048	.5204	58
5/8-11	17/32	.5313	79	.0049	.5362	75
	35/64	.5469	66	.0049	.5518	62
5/8-18	9/16	.5625	87	.0049	.5674	80
	37/64	.5781	65	.0049	.5831	58
3/4-10	41/64	.6406	84	.0050	.6456	80
	21/32	.6563	72	.0050	.6613	68
3/4-16	11/16	.6875	77	.0050	.6925	71
7/8-9	49/64	.7656	76	.0052	.7708	72
	25/32	.7812	65	.0052	.7864	61
7/8-14	51/64	.7969	84	.0052	.8021	79
	13/16	.8125	67	.0052	.8177	62
1-8	55/64	.8594	87	.0059	.8653	83
	7/8	.875	77	.0059	.8809	73
	57/64	.8906	67	.0059	.8965	64
	29/32	.9063	58	.0059	.9122	54
1-12	29/32	.9063	87	.0059	.9122	81
	59/64	.9219	72	.0060	.9279	67
	15/16	.9375	58	.0060	.9435	52
1-14	59-64	.9219	84	.0060	.9279	78
	15/16	.9375	67	.0060	.9435	61
1 1/8-7	31/32	.9688	84	.0062	.9750	81
	63/64	.9844	76	.0067	.9911	72
	1	1.000	67	.0070	1.007	64
	1 1/64	1.0156	59	.0070	1.0226	55
1 1/8-12	1 1/32	1.0313	87	.0071	1.0384	80
	1 3/64	1.0469	72	.0072	1.0541	66
1 1/4-7	1 3/32	1.0938	84	REAMING RECOMMENDED
	1 7/64	1.1094	76	REAMING RECOMMENDED
	1 1/8	1.125	67	REAMING RECOMMENDED
1 1/4-12	1 5/32	1.1563	87	REAMING RECOMMENDED
	1 11/64	1.1719	72	REAMING RECOMMENDED
1 3/8-6	1 3/16	1.1875	87	REAMING RECOMMENDED
	1 13/64	1.2031	79	REAMING RECOMMENDED
	1 7/32	1.2188	72	REAMING RECOMMENDED
	1 15/64	1.2344	65	REAMING RECOMMENDED
1 3/8-12	1 9/32	1.2813	87	REAMING RECOMMENDED
	1 19/64	1.2969	72	REAMING RECOMMENDED
1 1/2-6	1 5/16	1.3125	87	REAMING RECOMMENDED
	1 21/64	1.3281	79	REAMING RECOMMENDED
	1 11/32	1.3438	72	REAMING RECOMMENDED
	1 23/64	1.3594	65	REAMING RECOMMENDED
1 1/2-12	1 13/32	1.4063	87	REAMING RECOMMENDED
	1 27/64	1.4219	72	REAMING RECOMMENDED

TAP DRILL SIZES

Recommended tap drill sizes (for appx. 75% thread) — INCH and METRIC
provided by
VICTOR MACHINERY EXCHANGE, INC.


INCH SIZES - NATIONAL COARSE
TAP SIZE	DRILL SIZE
#0-80	3/64"
#1-64	#53
#2-56	#51
#3-48	5/64"
#4-40	#43
#5-40	#39
#6-32	#36
#8-32	#29
#10-24	#25
#12-24	#17
1/4-20	#7
5/16-18	F
3/8-16	5/16
7/16-14	U
1/2-13	27/64
9/16-12	31/64
5/8-11	17/32
3/4-10	21/32
7/8-9	49/64
1"-8	7/8
1-1/8-7	63/64
1-1/4-7	1-7/64
1-1/2-6	1-11/32
1-3/4-5	1-35/64
2"-4-1/2	1-25/32


INCH SIZES - NATIONAL FINE
TAP SIZE	DRILL SIZE
#1-72	#53
#2-64	#50
#3-56	#46
#4-48	#42
#5-44	#37
#6-40	#33
#8-36	#29
#10-32	#21
#12-28	#15
1/4-28	#3
5/16-24	I
3/8-24	Q
7/16-20	W
1/2-20	29/64
9/16-18	33/64
5/8-18	37/64
3/4-16	11/16
7/8-14	13/16
1"-14	15/16
1-1/8-12	1-3/64
1-1/4-12	1-11/64
1-1/2-12	1-27/64
1-3/4-12	1-43/64
2"-12	1-59/64


TAPER PIPE SIZES - NPT
TAP SIZE	DRILL SIZE
1/8-27	R
1/4-18	7/16
3/8-18	37/64
1/2-14	23/32
3/4-14	59/64
1"-11-1/2	1-5/32
1-1/4-11-1/2	1-1/2
1-1/2-11-1/2	1-47/64
2"-11-1/2	2-7/32
2-1/2-8	2-5/8
3"-8	3-1/4
3-1/2-8	3-3/4
4"-8	4-1/4


STRAIGHT PIPE SIZES - NPS
TAP SIZE	DRILL SIZE
1/8-27	S
1/4-18	29/64
3/8-18	19/32
1/2-14	47/64
3/4-14	15/16
1"-11-1/2	1-3/16
1-1/4-11-1/2	1-33/64
1-1/2-11-1/2	1-3/4
2"-11-1/2	2-7/32
2-1/2-8	2-21/32
3"-8	3-9/32
3-1/2-8	3-25/32
4"-8	4-9/32


METRIC COARSE SIZES
TAP SIZE	DRILL SIZE
1mm x .25	.75mm
1.1 x .25	.85
1.2 x .25	.95
1.4 x .3	1.1
1.6 x .35	1.25
1.7 x .35	1.3
1.8 x .35	1.45
2 x .4	1.6
2.2 x .45	1.75
2.5 x .45	2.05
3 x .5	2.5
3.5 x .6	2.9
4 x .7	3.3
4.5 x .75	3.7
5 x .8	4.2
6 x 1	5
7 x 1	6
8 x 1.25	6.8
9 x 1.25	7.8
10 x 1.5	8.5
11 x 1.5	9.5
12 x 1.75	10.2
14 x 2	12
16 x 2	14
18 x 2.5	15.5
20 x 2.5	17.5
22 x 2.5	19.5
24 x 3	21
27 x 3	24
30 x 3.5	26.5
33 x 3.5	29.5
36 x 4	32
39 x 4	35


METRIC FINE SIZES
TAP SIZE	DRILL SIZE
4 mm x .35	3.6mm
4 x .5	3.5
5 x .5	4.5
6 x .5	5.5
6 x .75	5.25
7 x .75	6.25
8 x .5	7
8 x .75	7.25
8 x 1	7.5
9 x 1	8
10 x .75	9.25
10 x 1	9
10 x 1.25	8.8
11 x 1	10
12 x .75	11.25
12 x 1	11
12 x 1.5	10.5
14 x 1	13
14 x 1.25	12.8
14 x 1.5	12.5
16 x 1	15
16 x 1.5	14.5
18 x 1	17
18 x 2	16
20 x 1	19
20 x 1.5	18.5
20 x 2	18
22 x 1	21
22 x 1.5	20.5
22 x 2	20
24 x 1.5	22.5
24 x 2	22
26 x 1.5	24.5
27 x 1.5	25.5
27 x 2	25
28 x 1.5	26.5
30 x 1.5	28.5
30 x 2	28
33 x 2	31
36 x 3	33
39 x 3	36

INCH SIZES - NATIONAL COARSE

----------------------------
TAP		DRILL
SIZE		SIZE
----------------------------
#1-64		#53 
#2-56 		#51 
#3-48 		5/64" 
#4-40 		#43 
#5-40 		#39 
#6-32 		#36 
#8-32 		#29 
#10-24 		#25 
#12-24 		#17 
1/4-20 		#7 
5/16-18 	F 
3/8-16 		5/16 
7/16-14		U 
1/2-13 		27/64 
9/16-12 	31/64 
5/8-11 		17/32 
3/4-10 		21/32 
7/8-9 		49/64 
1"-8 		7/8 
1-1/8-7 	63/64 
1-1/4-7 	1-7/64 
1-1/2-6 	1-11/32 
1-3/4-5 	1-35/64 
2"-4-1/2 	1-25/32
----------------------------

INCH SIZES - NATIONAL FINE

----------------------------
TAP		DRILL
SIZE 		SIZE
----------------------------
#0-80 		3/64" 
#1-72 		#53
#2-64 		#50
#3-56 		#46
#4-48 		#42
#5-44 		#37
#6-40 		#33
#8-36 		#29
#10-32 		#21
#12-28 		#15
1/4-28 		#3
5/16-24 	I
3/8-24 		Q
7/16-20 	W
1/2-20 		29/64
9/16-18 	33/64
5/8-18 		37/64
3/4-16 		11/16
7/8-14 		13/16
1"-14 		15/16
1-1/8-12 	1-3/64
1-1/4-12 	1-11/64
1-1/2-12 	1-27/64
1-3/4-12 	1-43/64
2"-12 		1-59/64
----------------------------

TAPER PIPE SIZES - NPT

----------------------------
TAP 		DRILL
SIZE 		SIZE
----------------------------
1/8-27 		R
1/4-18 		7/16
3/8-18 		37/64
1/2-14 		23/32
3/4-14 		59/64
1"-11-1/2 	1-5/32
1-1/4-11-1/2 	1-1/2
1-1/2-11-1/2 	1-47/64
2"-11-1/2	 2-7/32
2-1/2-8 	2-5/8
3"-8 		3-1/4
3-1/2-8 	3-3/4
4"-8 		4-1/4
----------------------------

STRAIGHT PIPE SIZES - NPS

----------------------------
TAP	 	DRILL
SIZE 		SIZE
----------------------------
1/8-27 		S
1/4-18 		29/64
3/8-18 		19/32
1/2-14 		47/64
3/4-14 		15/16
1"-11-1/2 	1-3/16
1-1/4-11-1/2 	1-33/64
1-1/2-11-1/2	1-3/4
2"-11-1/2	2-7/32
2-1/2-8 	2-21/32
3"-8 		3-9/32
3-1/2-8 	3-25/32
4"-8 		4-9/32
----------------------------