Tap-Drill Chart


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Decimal Equivalents and Tap Sizes of Fraction, Number, Letter and Metric Sizes

Recommended tap drill sizes for approximately 75% depth of thread

SIZES	DEC. INCHES	SIZES	DEC. INCHES	TAP SIZES To be used with drills as indicated	SIZES	DEC. INCHES	TAP SIZES To be used with drills as indicated	SIZES	DEC. INCHES	TAP SIZES To be used with drills as indicated	SIZES	DEC. INCHES	TAP SIZES To be used with drills as indicated
97	.0059	58	.0420		27	.1440		H	.2660		*17/32*	*.5312*	*5/8-11*
.15mm	.0059	57	.0430		3.7mm	.1457		6.8mm	.2677		13.5mm	.5315
96	.0063	1.1mm	.0433		26	.1470	3/16-24NS	6.9mm	.2717		*35/64*	*.5469*
.16mm	.0063	1.15mm	.0453		3.75mm	.1476	m4.5x0.75	I	2720	5/16-24 NF	14mm	5512	m16x2
95	.0067	56	.0465		25	.1495	#10-24	7mm	.2756	m8x1	*9/16*	*.5625*
.17mm	.0067	*3/64*	*.0469*	*#0-80*	3.8mm	.1496		J	.2770		14.5mm	.5709	m16x1.50
94	.0071	1.2mm	.0472		24	.1520		7.1mm	.2795		*37/64*	*.5781*	*3/8-18 NPT PIPE 5/8-18 NF*
.18mm	.0071	1.25mm	.0492	m1.6x0.35	3.9mm	.1535		K	.2810		15mm	.5906
93	.0075	1.3mm	.0512		23	.1540		*9/32*	*.2812*	*5/16-32 NS*	*19/32*	*.5938*	*3/8-18 NPS PIPE*
.19mm	.0075	55	.0520		*5/32*	*.1562*		7.2mm	.2835		*39/64*	*.6094*
92	.0079	1.35mm	.0531		22	.1570	3/16-32 NS	7.25mm	.2854		15.5mm	.6102	m18x2.5
.2mm	.0079	54	.0550		4mm	.1575		7.3mm	.2874		*5/8*	*.6250*	*11/16-16 NS*
91	.0083	1.4mm	.0551		21	.1590	#10-32	L	.2900		16mm	.6299	n18x2.0
.21mm	.0083	1.45mm	.0571	m1.8x0.35	20	.1610		7.4mm	.2913		*41/64*	*.6406*
90	.0087	1.5mm	.0591		4.1mm	.1614		M	.2950		16.5mm	.6496
.22mm	.0087	53	.0595	#1-64,72	4.2mm	.1654	m5x0.8	7.5mm	.2953		*21/32*	*.6562*	*3/4-10 NC*
89	.0091	1.55mm	.0610		19	.1660		*19/64*	*.2969*		17mm	.6693
.23mm	.0091	*1/16*	*.0625*		4.25mm	.1673		7.6mm	.2992		*43/64*	*.6719*
.24mm	.0094	1.6mm	.0630	m2x0.4	4.3mm	.1693		N	.3020		*11/16*	*.6875*	*3/4-16 NF*
88	.0095	52	.0635		18	.1695		7.7mm	.3031		17.5mm	.6890	m20x2.5
.25mm	.0098	1.65mm	.0650		*11/64*	*.1719*		7.75mm	.3051	m9x1.25	*45/64*	*.7031*
87	.0100	1.7mm	.0669		17	.1730		7.8mm	.3171		18mm	.7087	m20x2.0
.26mm	.0102	51	.0670	#2-56	4.4mm	.1732		7.9mm	.3110		*23/32*	*.7188*	*1/2-14 NPT PIPE*
86	.0105	1.75mm	.0689	m2.2x0.45	16	.1770	#12-24	*5/16*	*.3125*	*3/8-16 NC*	18.5mm	.7283	m20x1.5
.27mm	.0106	50	.0700	#2-64	4.5mm	.1772		8mm	.3150		*47/64*	*.7344*	*1/2-14 NPS PIPE*
85	.0110	1.8mm	.0709		15	.1800		O	.3160		19mm	.7480
.28mm	.0110	1.85mm	.0728		4.6mm	.1811		8.1mm	.3189		*3/4*	*.7500*
.29mm	.0114	49	.0730		14	.1820	#12-28	8.2mm	.3228		*49/64*	*.7656*	*7/8-9 NC*
84	.0115	1.9mm	.0748	m2.3x0.4	13	.1850		P	.3230		19.5mm	.7677	m22x2.5
.3mm	.0118	48	.0760		4.7mm	.1850		8.25mm	.3248		*25/32*	*.7812*
83	.0120	1.95mm	.0768		4.75mm	.1870		8.3mm	.3268		20mm	.7874	m22x2.0
82	.0125	*5/64*	*.0781*		*3/16*	*.1875*		*21/64*	*.3281*		*51/64*	*.7969*
.32mm	.0126	47	.0785	#3-48	4.8mm	.1890		8.4mm	.3307		20.5mm	.8071	m22x1.5
81	.0130	2mm	.0787		12	.1890	7/32-32 NS	Q	.3320	3/8-24 NF	*13/16*	*.8125*	*7/8-14 NF*
.34mm	.0134	2.05mm	.0807	m2.5x45	11	.1910		8.5mm	.3346	m10x1.5	21mm	.8268	m24-3
80	.0135	46	.0810		4.9mm	.1929		8.6mm	.3386		*53/64*	*.8281*
.35mm	.0138	45	.0820	#3-56	10	.1935		R	.3390	1/8-27 NPS PIPE	*27/32*	*.8438*
.36mm	.0142	2.1mm	.0827		9	.1960		8.7mm	.3425		21.5mm	.8465
79	.0145	2.15mm	.0846	m2.6x0.45	5mm	.1969	m6x1	*11/32*	*.3438*		*55/64*	*.8594*
.38mm	.0150	44	.0860	#4-36	8	.1990		8.75mm	.3445	m10x1.25	22mm	.8661	m24x2
*1/64*	.0156	2.2mm	.0866		5.1mm	.2008		8.8mm	.3465		*7/8*	*.8750*	*1-8 NC*
.4mm	.0157	2.25mm	.0886		7	.2010	1/4-20	S	.3480	1/8-27 NPS PIPE	22.25mm	.8760
78	.0160	43	.0890	#4-40	*13/64*	*.2031*		8.9mm	.3504		22.5mm	.8858	m24x1.50
.42mm	.0165	2.3mm	.0906		6	.2040		9mm	.3543	m10.x1.00	*57/64*	*.8906*
.44mm	.0173	2.35mm	.0925		5.2mm	.2047		T	.3580		23mm	.9055
.45mm	.0177	42	.0935	#4-48	5	.2055		9.1mm	.3583		*29/32*	*.9062*
77	.0180	*3/32*	*.0938*		5.25mm	.2067	m6x0.75	*23/64*	*.3594*		*59/64*	*.9219*	*3/4-14 NPT PIPE*
.46mm	.0181	2.4mm	.0945		5.3mm	.2087		9.2mm	.3622		23.5mm	.9252
.48mm	.0189	41	.0960		4	.2090	1/4-20	9.25mm	.3642		*15/16*	*.9375*	*3/4-14 NPS PIPE 1-1/4 NF*
.5mm	.0197	2.45mm	.0965		5.4mm	.2126		9.3mm	.3661		24mm	.9449
76	.0200	40	.0980		3	.2130	1/4-28	U	.3680	7/16-14 NC	*61/64*	*.9531*
75	.0210	2.5mm	.0984	m3-0.5	5.6mm	.2165		9.4mm	.3701		24.5mm	.9646
.55mm	.0217	39	.0995		*7/32*	*.2188*		9.5mm	.3740	m11x1.5	*31/32*	*.9688*
74	.0225	38	.1015	#5-40	5.6mm	.2205		*3/8*	*.3750*		25mm	.9843	m27-2
.6mm	.0236	2.6mm	.1024		2	.2210		V	.3770		*63/64*	*.9844*	*1-1/8-7 NC*
73	.0240	37	.1040	#5-44	5.7mm	.2244		9.6mm	.3780		1	*1.0000*
72	.0250	2.7mm	.1063		5.75mm	.2264		9.7mm	.3819		25.5mm	1.0039
.65mm	.0256	36	.1065	#6-32	1	.2280		9.75mm	.3839		*1-1/64*	*1.0156*
71	.0260	2.75mm	.1083		5.8mm	.2283		9.8mm	.3858		26mm	1.0236
.7mm	.0276	*7/64*	*.1094*		5.9mm	.2323		W	.3860		*1-1/32*	*1.0312*
70	.0280	35	.1100		A	.2340		9.9mm	.3898		26.5mm	1.0433	m30x3.5
69	.0292	2.8mm	.1102		*15/64*	*.2344*		*25/64*	*.3906*	*7/16-20*	*1-3/64*	*1.0469*	*1-1/8-12 NF*
.75mm	.0295	34	.1110		6mm	.2362	m7x1	10mm	.3937	m12x1.75	*1-1/16*	*1.0625*
68	.0310	33	.1130	#6-40	B	.2380		X	.3970		27mm	1.0630
*1/32*	*.0312*	2.9mm	.1142	m3.5x0.6	6.1mm	.2402		Y	.4040		*1-5/64*	*1.0781*
.8mm	.0315	32	.1160		C	.2420		*13/32*	*.4062*		27.5mm	1.0827
67	.0320	3mm	.1181		6.2mm	.2441		Z	.4130		*1-3/32*	*1.0928*
66	.0330	31	.1200		D	.2460	1/16-27 NPT PIPE	10.5mm	.4134	m12x1.25	28mm	1.1024	m30x2.0
.85mm	.0335	3.1mm	.1220		6.25mm	.2461		*27/64*	*.4219*	*1/2-13*	*1-7/64*	*1.1094*	*1-1/4-7 NC*
65	.0350	*1/8*	*.1250*	*5/32-32 NS*	6.3mm	.2480		11mm	.4331		28.5mm	1.1220
.9mm	.0354	3.2mm	.1260		E	.2500		*7/16*	*.4375*	*1/4-18 NPT PIPE*	*1-1/8*	*1.1250*
64	.0360	3.25mm	.1280		*1/4*	*.2500*	*1/16-27 NPS PIPE*	11.5mm	.4528		*1-9/64*	*1.1406*
63	.0370	30	.1285	5/32-36 NS	6.4mm	.2520		*29/64*	*.4531*	*1/4-18 NPS PIPE 1/2-20*	29mm	1.1417
.95mm	.0374	3.3mm	.1299	m4x0.7	6.5mm	.2559		*15/32*	*.4688*		*1-5/32*	*1.1562*	*1-11-1/2 NPT PIPE*
62	.0380	3.4mm	.1339		F	.2570	5/16-18 NC	12mm	.4724	m14x2	29.5mm	1.1614
61	.0390	29	.1360	#8-32	6.6mm	.2598		*31/64*	*.4844*	*9/16-12*	*1-11/64*	*1.1719*	*1-1/4-12 NF*
1mm	.0394	3.5mm	.1378		G	.2610		12.5mm	.4921	m14x1.5
60	.0400	28	.1405		6.7mm	.2638		*1/2*	*.5000*
59	.0410	*9/64*	*.1406*		*17/64*	*.2638*		13mm	.5118	m14x1.25
1.05mm	.0413	3.6mm	.1417		6.75mm	.2656	m8x1.25	*33/64*	*.5156*	*9/16-18*

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