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Drill and Tap Sizes

This drill and tap chart was copied from my old html site. It does not work well with WordPress. I need to come up with a new idea for displaying the dimensions and their tap sizes. This page is best viewed horizontally.

Drill Bit Sizes For Tapping New Threads

Minimum and maximum drill sizes are indicated for many taps. A smaller hole will have tighter threads, but will be more work to tap in hard materials. A smaller hole (Where 75% of the thread surfaces will make contact) is a good idea in soft metals such as copper or brass. Not responsible for errors and omissions regarding the content of this page.

Fraction (Inches)	Decimal (Inches)	Milli- meters	Drill Number or Letter	Tap (Size of Screw & Threads per Inch)	Tap Drill Size	Fine Pitch	Coarse Pitch
	.003937	.1mm
	.0059055	.15
	.007874	.2
	.0098425	.25
	.011811	.3
	.0135		80
	.0145		79
1/64	.015625	.39688
	.015748	.4
	.0160		78
	.0177165	.45
	.0180		77
	.019685	.5
	.0200		76
	.0210		75
	.0216535	.55
	.0225		74
	.023622	.6
	.0240		73
	.0250		72
	.0255905	.65
	.0260		71
	.0280		70
	.027559	.7
	.0292		69
	.0295275	.75
	.0310		68
1/32	.031250	.79375
	.031496	.8
	.0320		67
	.0330		66
	.0334645	.85
	.0350		65
	.035433	.9
	.0360		64
	.0370		63
	.0374015	.95
	.0380		62
	.0390		61

Fraction (Inches)	Decimal (Inches)	Milli- meters	Drill Number or Letter	Tap (Size of Screw & Threads per Inch)	Tap Drill Size	Fine Pitch	Coarse Pitch
	.03937	1mm				.2	.25
	.04		60
	.041		59
	.0413385	1.05
	.042		58
	.043		57
	.043307	1.1					.25
	.0452755	1.15
	.0465		56	0-80
3/64	.046875	1.19063		0-80 75%			.318
	.047244	1.2mm				.2	.25
	.048			0-80
	.0492125	1.25
	.051181	1.3
	.052		55	8-80 50%
	.0531495	1.35
	.055		54
	.055118	1.4mm				.2	.3
	.057			1-64
	.0570865	1.45
	.059			1-72
	.059055	1.5mm					.3
	.0595		53	1-64,1-72 75%
	.0610235	1.55
1/16	.062500	1.58750		1-64 50%
	.062992	1.6mm				.2	.35
	.0635		52	0
	.0635		52	1-72 50%
	.0649605	1.65
	.066929	1.7mm				.2, .25	.35
	.0670		51	2-56
	.068			2-56
	.0688975	1.75
	.0700		50	2-64
	.070866	1.8mm				.2	.35
	.0728345	1.85
	.0730		49
	.074803	1.9
	.0760		48	1
	.0767715	1.95
	.078			3-48
5/64	.078125	1.98438		3-48
	.0785		47	3-48

Fraction (Inches)	Decimal (Inches)	Milli- meters	Drill Number or Letter	Tap (Size of Screw & Threads per Inch)	Tap Drill Size	Fine Pitch	Coarse Pitch	Threads per Inch (TPI)
	.07874	M2				.25, .35	.4
	.0807085	2.05
	.0810		46	3-56
	.0820		45	3-56
	.082677	2.1
	.0846455	2.15
	.0860		44	4-40
	.086614	2.2mm					.45
	.087			4-40
	.0885825	2.25
	.0890		43	4-40
	.090551	2.3mm				.25, .35	.4
	.091			4-48
	.0925195	2.35
	.0935		42	4-48
3/32	.093750	2.38125		4-48
	.094488	2.4
	.0960		41
	.0964565	2.45
	.0980		40	5-40
	.098425	2.5mm				.35	.45
	.0995		39	5-40
	.100			5-40
	.1015		38	5-44
	.102			5-44
	.102362	2.6mm				.25, .35	.45
	.1040		37
	.106299	2.7
	.1065		36	6-32
	.107
	.1082675	2.75
7/64	.109375	2.77813		6-32
	.1100		35	6-32
	.110236	2.8
	.1110		34	6-32
	.1130		33	6-32, 6-40
	.114173	2.9
	.1160		32	6-32, 6-40
	.11811	M3			41, 2.6mm 75%	.35		73 TPI
	.11811	M3			2.5mm 75%		.5	51 TPI
	.1200		31	6-40
	.122047	3.1
1/8	.125000	3.17500
	.125984	3.2
	.1279525	3.25
	.1285	3.26390	30
	.129921	3.3
	.133
	.133858	3.4
	.1360	3.45440	29	8-32, 8-36 75%
	.137795	3.5mm				.35	.6
	.1405	3.56870	28	8-32, 8-36
9/64	.140625	3.571875
	.141732	3.6
	.1440		27	8-32 50%
	.145669	3.7
	.1470		26	8-36 50%
	.1476375	3.75
	.148
	.1495		25	10-24
	.149606	3.8
	.1520		24	10-24
	.153543	3.9
	.1540		23	10-24
5/32	.156250	3.96875		10-24
	.1570		22	10-24

Fraction (Inches)	Decimal (Inches)	Milli- meters	Drill Number or Letter	Tap (Size of Screw & Threads per Inch)	Tap Drill Size	Fine Pitch	Coarse Pitch
	.15748	M4				.5	.7
	.1590		21	10-24, 10-32
	.1610		20	10-24, 10-32
	.161417	4.1
	.165354	4.2
	.1660		19	10-32
	.1673225	4.25
	.169291	4.3
	.1695		18	10-32
11/64	.171875	4.36563
	.1730		17
	.173228	4.4
	.174
	.1770		16	12-24
	.177165	4.5mm					.75
	.1800		15	12-24
	.181102	4.6


	.1820		14	12-28
	.1850	4.7	13	12-28, 12-32
	.1870075	4.75
3/16	.187500	4.76250
	.188976	4.8	12	12-24, 12-28
	.1910		11	12-28
	.192913	4.9
	.1935		10
	.1960		9
	.196850	M5				.5	.8
	.1990		8
	.200
	.200787	5.1
13/64	.203125	5.15938		1/4-20
	.204724	5.2
	.2055		5	1/4-20
	.2066925	5.25

	.208661	5.3
	.2090		4	1/4-20
	.212598	5.4
	.2130		3	1/4-28
	.214			1/4-28
	.216535	5.5
7/32	.218750	5.55625		1/4-20, -28, -32
	.220472	5.6
	.2210		2
	.224409	5.7
	.2263775	5.75
	.2280		1	1/4-28, 1/4-32
	.228346	5.8
	.232283	5.9
	.2340		A
15/64	.234375	5.95313

Fraction (Inches)	Decimal (Inches)	Milli- meters	Drill Number or Letter	Tap (Size of Screw & Threads per Inch)	Tap Drill Size	Fine Pitch	Coarse Pitch
	.23622	M6				.75	1
	.238		B
	.240157	6.1
	.242		C
	.244094	6.2
	.246	6.25	D
	.248031	6.3
1/4	.25	6.35000	E
	.251968	6.4
	.255905	6.5
	.257		F	5/16-18
	.259842	6.6
	.261		G	5/16-18
	.263779	6.7
17/64	.265625	6.74688
	.2657475	6.75
	.266		H	5/16-24
	.267716	6.8
	.271			5/16-24
	.271653	6.9
	.272		I	5/16-24
	.27559	7mm					1
	.277		J
	.279527	7.1
	.2811		K
9/32	.28125	7.14375
	.283464	7.2
	.2854325	7.25
	.287401	7.3
	.29		L
	.291338	7.4
	.295		M
	.295275	7.5
19/64	.296875	7.54063
	.299212	7.6
	.302		N
	.303149	7.7
	.3051175	7.75
	.307086	7.8
	.311023	7.9
	.312			3/8-16
5/16	.3125	7.9375		3/8-16

Fraction (Inches)	Decimal (Inches)	Milli- meters	Drill Number or Letter	Tap (Size of Screw & Threads per Inch)	Tap Drill Size	Fine Pitch	Coarse Pitch
	.31496	M8				1	1.25
	.316		O	3/8-16
	.318897	8.1
	.322834	8.2
	.323		P
	.3248025	8.25
	.326771	8.3
21/64	.328125	8.33438		3/8-24
	.330708	8.4
	.332		Q	3/8-24
	.333			3/8-24
	.334645	8.5
	.338582	8.6
	.339		R
	.342519	8.7
11/32	.34375	8.73125
	.3444875	8.75
	.346456	8.8
	.348		S
	.350393	8.9
	.35433	9mm					1.25
	.358		T
	.358267	9.1
23/64	.359375	9.12813		7/16-14
	.362204	9.2
	.3641725	9.25
	.366			7/16-14
	.366141	9.3
	.368		U	7/16-14
	.370078	9.4
	.374015	9.5
3/8	.375	9.525
	.377		V
	.377952	9.6
	.381889	9.7
	.385826	9.8
	.386		W	7/16-20
	.388			7/16-20
	.389763	9.9
25/64	.390625	9.92188		7/16-20

Fraction (Inches)	Decimal (Inches)	Milli- meters	Drill Number or Letter	Tap (Size of Screw & Threads per Inch)	Tap Drill Size	Fine Pitch	Coarse Pitch
	.3937	M10				1.25	1.5
	.397		X
	.404		Y
13/32	.40625	10.31875
	.413		Z
	.413385	10.5
27/64	.421875	10.71563		1/2-13
	.423			1/2-13
	.43307	11mm				1	1.5
7/16	.4375	11.1125
	.45			1/2-20
	.452755	11.5
29/64	.453125	11.50938		1/2-20
15/32	.46875	11.90625
	.47244	M12				1.25, 1.5	1.75
	.479			9/16-12
31/64	.484375	12.30313		9/16-12
	.492125	12.5
1/2″	.5″	12.7		9/16-18
	.507			9/16-18
	.51181	13mm
33/64	.515625	13.09688
17/32	.53125	13.49375		5/8-11
	.531495	13.5
	.534			5/8-11
35/64	.546875	13.89063

Fraction (Inches)	Decimal (Inches)	Milli- meters	Drill Number or Letter	Tap (Size of Screw & Threads per Inch)	Tap Drill Size	Fine Pitch	Coarse Pitch
	.55118	M14				1.5	2
9/16	.5625	14.28750		5/8-18
	.569			5/8-18
	.570865	14.5
37/64	.578125	14.68438
	.59055	15mm
19/32	.59375	15.08125
39/64	.609375	15.47813
	.610235	15.5
5/8	.625	15.875
	.62992	M16				1.5
41/64	.640625	16.27188
	.649605	16.5
	.65			3/4-10
21/32	.65625	16.66875		3/4-10
	.66929	17mm
43/64	.671875	17.06563
11/16	.6875	17.4625		3/4-16
	.688			3/4-16
	.688975	17.5
45/64	.703125	17.85938
	.70866	M18				1.5
23/32	.71875	18.25625
	.728345	18.5
47/64	.734375	18.65313
	.74803	19mm
3/4	.75	19.05
	.764			7/8-9
49/64	.765625	19.44668		7/8-9
	.767715	19.5
25/32	.78125	19.84375

Fraction (Inches)	Decimal (Inches)	Milli- meters	Drill Number or Letter	Tap (Size of Screw & Threads per Inch)	Tap Drill Size	Fine Pitch	Coarse Pitch
	.7874	M20				1.5
51/64	.796875	20.24063		7/8-14
	.804			7/8-14
13/16	.8125	20.6375
	.82677	21mm
53/64	.828125	21.03438
27/32	.84375	21.43125
	.846455	21.5


55/64	.859375	21.83813
	.86614	22mm
7/8	.875	22.225		1″-8
	.885825	22.5
57/64	.890625	22.62187		1″-8
	.905510	23mm
29/32	.90625	23.01875
59/64	.921875	23.41563		1″-12, 1″-14
	.925195	23.5
	.929			1″-14
15/16	.9375	23.81250		1″-14
	.94488	M24				1.5
61/64		24.209
	.964565	24.5
	.982	25mm		1 1/8″-7
63/64	.984375	25.00312		1 1/8″-7
1″	1.000″	25.40000		1 1/8″-7