Drill and Tap Charts - Inch & Metric

INCH TAP DRILL SIZES
Recommended tap drill sizes (for approx. 75% thread)		
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
----------------------------	

METRIC TAP DRILL SIZES
Recommended tap drill sizes (for approx. 75% thread) 			
METRIC COARSE SIZES
----------------------------
TAP                 DRILL
SIZE                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                 DRILL
SIZE                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
----------------------------		
Handy Helpers!
Tap Drill Sizes (inch) for a 75% Thread
In general, you can find the tap-drill for any size 60 degree thread, subtract one pitch length from the major diameter. 
Formula: Major Dia. minus One Pitch Length equals tap-drill size 
English Example for 3/8-16 thread: .375 - .0625 = .3125 tap-drill (5/16) 
Metric Example for M6 X 1 thread: 6mm - 1mm = 5mm tap-drill			

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Tap Drill Chart Metric

0M1.6 - M20 | M22 - M38 

NOMINAL TAP SIZE	T.P.I.	TAP DRILL 	DEC EQUIV.	% OF THREAD	NOMINAL TAP SIZE	T.P.I.	TAP DRILL 	DEC EQUIV.	% OF THREAD	
M1.6	0.35	1.25MM	.0492	77	M8.0	1.25	6.75MM	.2657	77	
		1.30MM	.0512	66			6.80MM	.2677	74	
		#55	.0520	61			LTR I	.2720	67	
M1.8	0.35	1.45MM	.0571	77	M8.0	1.0	7.00MM	.2756	77	
		1.50MM	.0591	66			LTR J	.2770	74	
		#53	.0595	64	M10.0	1.5	8.50MM	.3346	77	
M2.0	0.40	1.60MM	.0630	77			LTR R	.3390	71	
		#52	.0635	74	M10.0	1.25	8.75MM	.3445	77	
M2.2	0.45	1.75MM	.0689	77			LTR S	.3480	71	
		#50	.0700	72	M12.0	1.75	13/32	.4062	74	
M2.5	0.45	2.05MM	.0807	77			LTR Z	.4130	66	
		#45	.0820	71	M12.0	1.25	27/64	.4219	79	
M3.0	0.50	2.50MM	.0984	77			11.0MM	.4331	62	
		#39	.0995	73	M14.0	2.0	12.0MM	.4727	77	
M3.5	0.60	2.90MM	.1142	77			31/64	.4844	65	
		#32	.1160	71	M14.0	1.5	12.5 MM	.4921	77	
M4.0	0.70	3.30 MM	.1299	77			1/2	.5000	67	
		3.40 MM	.1339	66	M16.0	2.0	14.0 MM	.5512	77	
		#29	.1360	60			9/16	.5625	66	
M4.5	0.75	3.75 MM	.1476	77	M16.0	1.5	14.5 MM	.5709	77	
		#25	.1495	72			37/64	.5781	68	
M5.0	0.80	4.20 MM	.1654	77	M18.0	2.5	15.5 MM	.6102	77	
		#18	.1695	67			5/8	.6250	65	
M6.0	1.00	5.00 MM	.1969	77	M18.0	1.5	16.5 MM	.6496	77	
		#8	.1990	73			21/43	.6562	68	
M7.0 	1.00	6.00 MM	.2362	77	M20.0	1.5	18.5 MM	.7283	77	
##	#	LTR B	.2380	74	M20.0	1.5 	47/64	.7344	69	

NOMINAL TAP SIZE	T.P.I.	TAP DRILL 	DEC EQUIV.	% OF THREAD	
M22.0	2.5	19.5 MM	.7677	77	
	#	25/32	.7812	66	
M22.0	1.5	20.5 MM	.8071	77	
	#	13/16	.8125	70	
M24.0	3.0	21.0 MM	.8268	77	
	#	27/32	.8438	66	
M24.0	2.0	22.0 MM	.8661	77	
	#	7/8	.8750	68	
M27.0	3.0	24.0 MM	.9449	77	
	#	61/64	.9531	72	
M27.0	2.0	25.0 MM	.9843	77	
	#	63/64	.9844	77	
M30.0	3.5	26.5 MM	1.0433	77	
	#	1-1/16	1.0625	66	
M30.0	2.0	28.0 MM	1.1024	77	
	##	1-7/64	1.1094	70	
M33.0	3.5	29.5 MM	1.1614	77	
	#	1-11/64	1.1719	71	
M33.0	2.0	31.0 MM	1.2205	77	
	#	1-15/64	1.2344	63	
M36.0	4.0	32.0 MM	1.2598	77	
	#	1-17/64	1.2656	74	
M36.0	3.0	1-19/64	1.2969	78	
	#	1-5/16	1.3125	68	
M38.0	4.0	34.0MM	1.3386	77	
M38.0	#	1-23/64	1.3594	63	

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Monday - Friday
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beeind.com 
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Phone: (510) 293-3180
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USA

METRIC THREAD - Drill & Tap Chart 
Course Thread Sizes
Thread Size	Tap Drill (mm)	Thread Size	Tap Drill (mm)	Thread Size	Tap Drill (mm)	Thread Size	Tap Drill (mm)	
M1 x 0.25	0.75	M3.5 x 0.6	2.90	M12 x 1.75	10.20	M36 x 4	32.00	
M1.1 x 0.25	0.85	M4 x 0.7	3.30	M14 x 2	12.00	M39 x 4	35.00	
M1.2 x 0.25	0.95	M4.5 x 0.75	3.70	M16 x 2	14.00	M42 x 4.5	37.50	
M1.4 x 0.3	1.10	M5 x 0.8	4.20	M18 x 2.5	15.50	M45 x 4.5	40.50	
M1.6 x 0.35	1.25	M6 x 1	5.00	M20 x 2.5	17.50	M48 x 5	43.00	
M1.8 x 0.35	1.45	M7 x 1	6.00	M22 x 2.5	19.50	M52 x 5	47.00	
M2 x 0.4	1.60	M8 x 1.25	6.80	M24 x 3	21.00	M56 x 5.5	50.50	
M2.2 x 0.45	1.75	M9 x 1.25	7.80	M27 x 3	24.00	M60 x 5.5	54.50	
M2.5 x 0.45	2.05	M10 x 1.5	8.50	M30 x 3.5	26.50	M64 x 6	58.00	
M3 x 0.5	2.50	M11 x 1.5	9.50	M33 x 3.5	29.50	M68 x 6	62.00	

Fine Thread Sizes
Thread Size	Tap Drill (mm)	Thread Size	Tap Drill (mm)	Thread Size	Tap Drill (mm)	Thread Size	Tap Drill (mm)	
M4 x 0.35	3.60	M10 x 0.75	9.25	M16 x 1	15.0	M24 x 1.5	22.5	
M4 x 0.5	3.50	M10 x 1	9.0	M16 x 1.5	15.0	M24 x 2	22.0	
M5 x 0.5	4.50	M10 x 1.25	8.8	M18 x 1	17.0	M26 x 1.5	24.5	
M6 x .5	5.50	M11 x 1	10.0	M18 x 2	16.0	M27 x 1.5	25.5	
M6 x .75	5.25	M12 x .75	11.25	M20 x 1	19.0	M27 x 2	25.0	
M7 x .75	6.25	M12 x 1	11.0	M20 x 1.5	18.5	M28 x 1.5	26.5	
M8 x .5	7.00	M12 x 1.5	10.5	M20 x 2	18.0	M30 x 1.5	28.5	
M8 x .75	7.25	M14 x 1	13.0	M22 x 1	21.0	M30 x 2	28.0	
M8 x 1	7.50	M14 x 1.25	12.8	M22 x 1.5	20.5	M33 x 2	31.0	
M9 x 1	8.00	M14 x 1.5	12.5	M22 x 2	20.0	M36 x 3	36.0	
Steven L Henderson's Cutting Edge Designs 

Tap Chart - Metric Threads

Tap size	Basic major
dia (mm)	Basic major dia
(inch)	mm per thread	Drill size
(mm)	Drill size
(inch)	
M1.6 x 0.35	1,6mm	.0630	.35	1,25mm	#55	
M2 x 0.4	2mm	.0787	.4	1,6mm	#52	
M2.5 x 0.45	2,5mm	.0984	.45	2,05mm	#46	
M3 x .05	3mm	.1181	.5	2,5mm	#39	
M3.5 x 0.6	3,5mm	.1378	.6	2,9mm	#32	
M4 x 0.7	4mm	.1575	.7	3,3mm	#30	
M5 x 0.8	5mm	.1969	.8	4,2mm	#19	
M6 x 1	6mm	.2362	1	5mm	#8	
M8 x 1.25	8mm	.3150	1.25	6,8mm	H	
M8 x 1	8mm	.3150	1	7mm	J	
M10 x 1.5	10mm	.3937	1.5	8,5mm	R	
M10 x 1.25	10mm	.3937	1.25	8,8mm	11/32	
M12 x 1.75	12mm	.4724	1.75	10,2mm	13/32	
M12 x 1.25	12mm	.4724	1.25	10,8mm	27/64	
M14 x 2	14mm	.5512	2	12mm	15/32	
M14 x 1.5	14mm	.5512	1.5	12,5mm	1/2	
M16 x 2	16mm	.6299	2	14mm	35/64	
M16 x 1.5	16mm	.6299	1.5	14,5mm	37/64	
M18 x 2.5	18mm	.7087	2.5	15,5mm	39/64	
M18 x 1.5	18mm	.7087	1.5	16,5mm	21/32	
M20 x 2.5	20mm	.7874	2.5	17,5mm	11/16	
M20 x 1.5	20mm	.7874	1.5	18,5mm	47/64	
M22 x 2.5	22mm	.8661	2.5	19,5mm	49/64	
M22 x 1.5	22mm	.8661	1.5	20,5mm	13/16	
M24 x 3	24mm	.9449	3	21mm	53/64	
M24 x 2	24mm	.9449	2	22mm	7/8	
M27 x 3	27mm	1.0630	3	24mm	15/16	
M27 x 2	27mm	1.0630	2	25mm	1	

- SAE Tap & Drill Chart -	
	
Thread
Size	Drill
Diameter
(in)	Tap Drill
Size	
	Thread
Size	Drill
Diameter
(in)	Tap Drill
Size		
Coarse Thread				Fine Thread				
1-64	.0595	No. 53		0-80	.0469	3/64		
2-56	.0700	No. 50		1-72	.0595	No. 53		
3-48	.0785	No. 47		2-64	.0700	No. 50		
4-40	.0890	No. 43		3-56	.0820	No. 45		
5-40	.1015	No. 38		4-48	.0935	No. 42		
6-32	.1065	No. 36		5-44	.1040	No. 37		
8-32	.1360	No. 29		6-40	.1130	No. 33		
10-24	.1495	No. 25		8-36	.1360	No. 29		
12-24	.1770	No. 16		10-32	.1590	No. 21		
1/4-20	.2010	No. 7		12-28	.1820	No. 14		
5/16-18	.2570	'F'		1/4-28	.2130	No. 3		
3/8-16	.3125	5/16		5/16-24	.2720	'I'		
7/16-14	.3680	'U'		3/8-24	.3320	'Q'		
1/2-13	.4219	27/64		7/16-20	.3906	25/64		
9/16-12	.4844	31/64		1/2-20	.4531	29/64		
5/8-11	.5312	17/32		9/16-18	.5156	33/64		
3/4-10	.6562	21/32		5/8-18	.5781	37/64		
7/8-9	.7656	49/64		3/4-16	.6875	11/16		
1"-8	.8750	7/8		7/8-14	.8125	13/16		
				1"-14	.9375	59/64		

Legend 				
Fractional Inch				
Letter Drill				
Millimeters				
Number Drill				
Millimeters 	Inches 	Designation 	Tap Drill/Pilot 	
.3429mm	.0135"	#80		
.3683mm	.0145"	#79		
.3969mm	.015625"	1/64"	#0 Pilot, Soft-Wood	
.4064mm	.016"	#78		
.4572mm	.018"	#77		
.5mm	.0197"			
.508mm	.02"	#76		
.5334mm	.021"	#75		
.5715mm	.0225"	#74		
.6096mm	.024"	#73		
.635mm	.025"	#72		
.6604mm	.026"	#71		
.7112mm	.028"	#70		
.74168mm	.0292"	#69		
.75mm	.0295"		M1x.25 coarse	
.7874mm	.031"	#68		
.7938mm	.03125"	1/32"	#0 Pilot, Hard-Wood #1 Pilot, Hard & Soft-Wood #2 Pilot, Soft-Wood	
.8128mm	.032"	#67		
.8382mm	.033"	#66		
.85mm	.0335"		M1.1x.25 coarse	
.889mm	.035"	#65		
.9144mm	.036"	#64		
.9398mm	.037"	#63		
.95mm	.0374"		M1.2x.25 coarse	
.9652mm	.038"	#62		
.9906mm	.039"	#61		
1mm	.0394"			
1.016mm	.04"	#60		
1.0414mm	.041"	#59		
1.0668mm	.042"	#58		
1.0922mm	.043"	#57		
1.1mm	.0433"		M1.4x.3 coarse	
1.1811mm	.0465"	#56		
1.1906mm	.046875"	3/64"	#0-80 UNF #2 Pilot, Hard-wood #3 Pilot, Soft-Wood #4 Pilot, Soft-Wood	
1.25mm	.0492"		M1.6x.35 coarse	
1.3mm	.0512"		M1.7x.35 coarse	
1.3208mm	.052"	#55		
1.397mm	.055"	#54		
1.45mm	.0571"		M1.8x.35 coarse	
1.5mm	.0591"			
1.5113mm	.0595"	#53	#1-64 UNC #1-72 UNF	
1.5875mm	.0625"	1/16"	#0 Wood Shank Hole #3 Pilot, Hard-Wood #4 Pilot, Hard-wood #5 Pilot, Soft-wood #6 Pilot, Soft-wood #7 Pilot, Soft-wood	
1.6mm	.063"		M2x.4 coarse	
1.6129mm	.0635"	#52		
1.7018mm	.067"	#51		
1.75mm	.0689"		M2.2x.45 coarse	
1.778mm	.07"	#50	#2-64 UNF #2-56 UNC	
1.8542mm	.073"	#49		
1.9304mm	.076"	#48		
1.9844mm	.078125"	5/64"	#1 Wood Shank Hole #5 Pilot, Hard-wood #6 Pilot, Hard-wood #8 Pilot, Soft-wood #9 Pilot, Soft-wood	
1.9939mm	.0785"	#47	#3-48 UNC	
2mm	.0787"			
2.05mm	.0807"		M2.5x.45 coarse	
2.0574mm	.081"	#46		
2.0828mm	.082"	#45	#3-56 UNF	
2.1844mm	.086"	#44		
2.2606mm	.089"	#43	#4-40 UNC	
2.3749mm	.0935"	#42	#4-48 UNF	
2.3813mm	.09375"	3/32"	#2 Wood Shank Hole #7 Pilot, Hard-wood #8 Pilot, Hard-wood #10 Pilot, Soft-wood #11 Pilot, Soft-wood	
2.4384mm	.096"	#41		
2.4892mm	.098"	#40		
2.5mm	.0984"		M3x.5 coarse	
2.5273mm	.0995"	#39		
2.5781mm	.1015"	#38	#5-40 UNC	
2.6416mm	.104"	#37	#5-44 UNF	
2.7051mm	.1065"	#36	#6-32 UNC	
2.7781mm	.109375"	7/64"	#3 Wood Shank Hole #4 Wood Shank Hole #9 Pilot, Hard-wood #10 Pilot, Hard-wood #12 Pilot, Soft-wood #14 Pilot, Soft-wood	
2.794mm	.11"	#35		
2.8194mm	.111"	#34		
2.8702mm	.113"	#33	#6-40 UNF	
2.9mm	.1142"		M3.5x.6 coarse	
2.9464mm	.116"	#32		
3mm	.1181"			
3.048mm	.12"	#31		
3.175mm	.125"	1/8"	#5 Wood Shank Hole #11 Pilot, Hard-wood #12 Pilot, Hard-wood	
3.2639mm	.1285"	#30		
3.3mm	.1299"		M4x.7 coarse	
3.4544mm	.136"	#29	#8-32 UNC #8-36 UNF	
3.5mm	.1378"		M4x.5 Fine	
3.5687mm	.1405"	#28		
3.5719mm	.140625"	9/64"	#6 Wood Shank Hole #14 Pilot, Hard-wood #16 Pilot, Soft-wood #18 Pilot, Soft-wood	
3.6mm	.1417"		M4x.35 Fine	
3.6576mm	.144"	#27		
3.7mm	.1457"		M4.5x.75 coarse	
3.7338mm	.147"	#26		
3.7973mm	.1495"	#25	#10-24 UNC	
3.8608mm	.152"	#24		
3.9116mm	.154"	#23		
3.9688mm	.15625"	5/32"	#7 Wood Shank Hole #16 Pilot, Hard-wood	
3.9878mm	.157"	#22		
4mm	.1575"			
4.0386mm	.159"	#21	#10-32 UNF	
4.0894mm	.161"	#20		
4.2mm	.1654"		M5x.8 coarse	
4.2164mm	.166"	#19		
4.3053mm	.1695"	#18		
4.3656mm	.171875"	11/64"	#8 Wood Shank Hole #20 Pilot, Soft-wood	
4.3942mm	.173"	#17	#12-24 UNC	
4.4958mm	.177"	#16		
4.5mm	.1772"		M5x.5 Fine	
4.572mm	.18"	#15	#12-28 UNF	
4.6228mm	.182"	#14		
4.699mm	.185"	#13		
4.7625mm	.1875"	3/16"	#9 Wood Shank Hole #10 Wood Shank Hole #18 Pilot, Hard-wood	
4.8006mm	.189"	#12		
4.8514mm	.191"	#11		
4.9149mm	.1935"	#10		
4.9784mm	.196"	# 9		
5mm	.1969"		M6x1 coarse	
5.0546mm	.199"	# 8		
5.1054mm	.201"	# 7	¼"-20 UNC	
5.1594mm	.203125"	13/64"	#11 Wood Shank Hole #20 Pilot, Hard-wood	
5.1816mm	.204"	# 6		
5.2197mm	.2055"	# 5		
5.25mm	.2067"		M6x.75 Fine	
5.3086mm	.209"	# 4		
5.4102mm	.213"	# 3	¼"-28 UNF	
5.5mm	.2165"		M6x.5 Fine	
5.5563mm	.21875"	7/32"	#12 Wood Shank Hole	
5.6134mm	.221"	# 2		
5.7912mm	.228"	# 1		
5.9436mm	.234"	A		
5.9531mm	.234375"	15/64"		
6mm	.2362"		M7x1 coarse	
6.0452mm	.238"	B		
6.1468mm	.242"	C		
6.2484mm	.246"	D	1/16"-27 NPT	
6.25mm	.2461"		M7x.75 Fine	
6.35mm	.25"	1/4"	#14 Wood Shank Hole	
6.35mm	.25"	E		
6.5mm	.2559"			
6.5278mm	.257"	F	5/16"-18 UNC	
6.6294mm	.261"	G		
6.7469mm	.265625"	17/64"	#16 Wood Shank Hole	
6.7564mm	.266"	H		
6.8mm	.2677"		M8x1.25 coarse	
6.9088mm	.272"	I	5/16"-24 UNF	
7mm	.2756"		M8x.5 Fine	
7.0358mm	.277"	J		
7.1374mm	.281"	K		
7.1438mm	.28125"	9/32"		
7.25mm	.2854"		M8x.75 Fine	
7.366mm	.29"	L		
7.493mm	.295"	M		
7.5mm	.2953"		M8x1 Fine	
7.5406mm	.296875"	19/64"	#18 Wood Shank Hole	
7.6708mm	.302"	N		
7.8mm	.3071"		M9x1.25 coarse	
7.9375mm	.3125"	5/16"	3/8"-16 UNC	
8mm	.315"		M9x1 Fine	
8.0264mm	.316"	O		
8.2042mm	.323"	P		
8.3344mm	.328125"	21/64"	#20 Wood Shank Hole	
8.4328mm	.332"	Q	3/8"-24 UNF	
8.5mm	.3346"		M10x1.5 coarse	
8.6106mm	.339"	R	1/8"-27 NPT	
8.7313mm	.34375"	11/32"		
8.8mm	.3465"		M10x1.25 Fine	
8.8392mm	.348"	S		
9mm	.3543"		M10x1 Fine	
9.0932mm	.358"	T	7/16"-14 UNC	
9.1281mm	.359375"	23/64"		
9.25mm	.3642"		M10x.75 Fine	
9.3472mm	.368"	U		
9.5mm	.374"		M11x1.5 coarse	
9.525mm	.375"	3/8"		
9.5758mm	.377"	V		
9.8044mm	.386"	W		
9.9219mm	.390625"	25/64"	7/16"-20 UNF	
10mm	.3937"		M11x1 Fine	
10.0838mm	.397"	X		
10.2mm	.4016"		M12x1.75 coarse	
10.2616mm	.404"	Y		
10.3188mm	.40625"	13/32"		
10.4902mm	.413"	Z		
10.5mm	.4134"		M12x1.5 Fine	
10.7156mm	.421875"	27/64"	½"-13 UNC	
11mm	.4331"		M12x1 Fine	
11.1125mm	.4375"	7/16"	¼"-18 NPT	
11.25mm	.4429"		M12x.75 Fine	
11.5mm	.4528"			
11.5094mm	.453125"	29/64"	½"-20 UNF	
11.9063mm	.46875"	15/32"		
12mm	.4724"		M14x2 coarse	
12.3031mm	.484375"	31/64"	9/16"-12 UNC	
12.5mm	.4921"		M14x1.5 Fine	
12.7mm	.5"	1/2"		
12.8mm	.5039"		M14x1.25 Fine	
13mm	.5118"		M14x1 Fine	
13.0969mm	.515625"	33/64"	9/16"-18 UNF	
13.4938mm	.53125"	17/32"	5/8"-11 UNC	
13.5mm	.5315"			
13.8906mm	.546875"	35/64"		
14mm	.5512"		M16x2 coarse	
14.2875mm	.5625"	9/16"	5/8"-18 UNF	
14.5mm	.5709"		M16x1.5 Fine	
14.6844mm	.578125"	37/64"	3/8"-18 NPT	
15mm	.5906"		M16x1 Fine	
15.0813mm	.59375"	19/32"		
15.4781mm	.609375"	39/64"		
15.5mm	.6102"		M18x2.5 coarse	
15.875mm	.625"	5/8"		
16mm	.6299"		M18x2 Fine	
16.2719mm	.640625"	41/64"	¾"-10 UNC	
16.5mm	.6496"			
16.6688mm	.65625"	21/32"		
17mm	.6693"		M18x1 Fine	
17.0656mm	.671875"	43/64"		
17.4625mm	.6875"	11/16"	¾"-16 UNF	
17.5mm	.689"		M20x2.5 coarse	
17.8594mm	.703125"	45/64"	½"-14 NPT	
18mm	.7087"		M20x2 Fine	
18.2563mm	.71875"	23/32"		
18.5mm	.7283"		M20x1.5 Fine	
18.6531mm	.734375"	47/64"		
19mm	.748"		M20x1 Fine	
19.05mm	.75"	3/4"		
19.4469mm	.765625"	49/64"	7/8"-9 UNC	
19.5mm	.7677"		M22x2.5 coarse	
19.8438mm	.78125"	25/32"		
20mm	.7874"		M22x2 Fine	
20.2406mm	.796875"	51/64"		
20.5mm	.8071"		M22x1.5 Fine	
20.6375mm	.8125"	13/16"	7/8"-14 UNF	
21mm	.8268"		M24x3 coarse M22x1 Fine	
21.0344mm	.828125"	53/64"		
21.4313mm	.84375"	27/32"		
21.5mm	.8465"			
21.8281mm	.859375"	55/64"		
22mm	.8661"		M24x2 Fine	
22.225mm	.875"	7/8"	1"-8 UNC	
22.5mm	.8858"		M24x1.5 Fine	
22.6219mm	.890625"	57/64"		
23mm	.9055"			
23.0188mm	.90625"	29/32"	1"-12 UNF	
23.4156mm	.921875"	59/64"	¾"-14 NPT	
23.5mm	.9252"			
23.8125mm	.9375"	15/16"		
24mm	.9449"		M27x3 coarse	
24.2094mm	.953125"	61/64"		
24.5mm	.9646"		M26x1.5 Fine	
24.6063mm	.96875"	31/32"		
25mm	.9843"		M27x2 Fine	
25.0031mm	.984375"	63/64"	1-1/8"-7 UNC	
25.4mm	1.000"	1"		
25.5mm	1.0039"		M27x1.5 Fine	
26.5mm	1.0433"		M30x3.5 coarse	
26.5mm	1.0433"		M28x1.5 Fine	
26.5906mm	1.046875"	1-3/64"	1-1/8"-12 UNF	
26.9875mm	1.0625"	1-1/16"		
28mm	1.1024"		M30x2 Fine	
28.1781mm	1.109375"	1-7/64"	1¼"-7 UNC	
28.5mm	1.122"		M30x1.5 Fine	
28.575mm	1.125"	1-1/8"		
29.3688mm	1.15625"	1-5/32"	1"-11½ NPT	
29.5mm	1.1614"		M33x3.5 coarse	
29.7656mm	1.171875"	1-11/64"	1¼"-12 UNF	
30.1625mm	1.1875"	1-3/16"		
31mm	1.2205"		M33x2 Fine	
32mm	1.2598"		M36x4 coarse	
33mm	1.2992"		M36x3 Fine	
34.1313mm	1.34375"	1-11/32"	1½"-6 UNC	
34.925mm	1.375"	1-3/8"		
35mm	1.378"		M39x4 coarse	
36mm	1.4173"		M39x3 Fine	
36.1156mm	1.421875"	1-27/64"	1½"-12 UNF	
36.5125mm	1.4375"	1-7/16"		
38.1mm	1.5"	1½"	1¼"-11½ NPT	
39.2906mm	1.546875"	1-35/64"	1¾"-5 UNC	
39.6875mm	1.5625"	1-9/16"		
41.275mm	1.625"	1-5/8"		
42.4656mm	1.671875"	1-43/64"	1¾"-12 UNF	
44.0531mm	1.734375"	1-47/64"	1½"-11½ NPT	
44.45mm	1.75"	1-3/4"		
45.2438mm	1.78125"	1-25/32"	2"-4½ UNC	
46.0375mm	1.8125"	1-13/16"		
47.625mm	1.875"	1-7/8"		
48.8156mm	1.921875"	1-59/64"	2"-12 UNF	
49.2125mm	1.9375"	1-15/16"		
56.3563mm	2.21875"	2-7/32"	2"-11½ NPT	
66.675mm	2.625"	2-5/8"	2½-8 NPT	
82.55mm	3.25"	3¼"	3"-8 NPT	
88.9mm	3.5"	3¾"	3½"-8 NPT	
107.95mm	4.25"	4¼	4"-8 NPT	

Legend 				
Fractional Inch				
Letter Drill				
Millimeters				
Number Drill				
Millimeters 	Inches 	Designation 	Tap Drill/Pilot 	
.3429mm	.0135"	#80		
.3683mm	.0145"	#79		
.3969mm	.015625"	1/64"	#0 Pilot, Soft-Wood	
.4064mm	.016"	#78		
.4572mm	.018"	#77		
.5mm	.0197"			
.508mm	.02"	#76		
.5334mm	.021"	#75		
.5715mm	.0225"	#74		
.6096mm	.024"	#73		
.635mm	.025"	#72		
.6604mm	.026"	#71		
.7112mm	.028"	#70		
.74168mm	.0292"	#69		
.75mm	.0295"		M1x.25 coarse	
.7874mm	.031"	#68		
.7938mm	.03125"	1/32"	#0 Pilot, Hard-Wood #1 Pilot, Hard & Soft-Wood #2 Pilot, Soft-Wood	
.8128mm	.032"	#67		
.8382mm	.033"	#66		
.85mm	.0335"		M1.1x.25 coarse	
.889mm	.035"	#65		
.9144mm	.036"	#64		
.9398mm	.037"	#63		
.95mm	.0374"		M1.2x.25 coarse	
.9652mm	.038"	#62		
.9906mm	.039"	#61		
1mm	.0394"			
1.016mm	.04"	#60		
1.0414mm	.041"	#59		
1.0668mm	.042"	#58		
1.0922mm	.043"	#57		
1.1mm	.0433"		M1.4x.3 coarse	
1.1811mm	.0465"	#56		
1.1906mm	.046875"	3/64"	#0-80 UNF #2 Pilot, Hard-wood #3 Pilot, Soft-Wood #4 Pilot, Soft-Wood	
1.25mm	.0492"		M1.6x.35 coarse	
1.3mm	.0512"		M1.7x.35 coarse	
1.3208mm	.052"	#55		
1.397mm	.055"	#54		
1.45mm	.0571"		M1.8x.35 coarse	
1.5mm	.0591"			
1.5113mm	.0595"	#53	#1-64 UNC #1-72 UNF	
1.5875mm	.0625"	1/16"	#0 Wood Shank Hole #3 Pilot, Hard-Wood #4 Pilot, Hard-wood #5 Pilot, Soft-wood #6 Pilot, Soft-wood #7 Pilot, Soft-wood	
1.6mm	.063"		M2x.4 coarse	
1.6129mm	.0635"	#52		
1.7018mm	.067"	#51		
1.75mm	.0689"		M2.2x.45 coarse	
1.778mm	.07"	#50	#2-64 UNF #2-56 UNC	
1.8542mm	.073"	#49		
1.9304mm	.076"	#48		
1.9844mm	.078125"	5/64"	#1 Wood Shank Hole #5 Pilot, Hard-wood #6 Pilot, Hard-wood #8 Pilot, Soft-wood #9 Pilot, Soft-wood	
1.9939mm	.0785"	#47	#3-48 UNC	
2mm	.0787"			
2.05mm	.0807"		M2.5x.45 coarse	
2.0574mm	.081"	#46		
2.0828mm	.082"	#45	#3-56 UNF	
2.1844mm	.086"	#44		
2.2606mm	.089"	#43	#4-40 UNC	
2.3749mm	.0935"	#42	#4-48 UNF	
2.3813mm	.09375"	3/32"	#2 Wood Shank Hole #7 Pilot, Hard-wood #8 Pilot, Hard-wood #10 Pilot, Soft-wood #11 Pilot, Soft-wood	
2.4384mm	.096"	#41		
2.4892mm	.098"	#40		
2.5mm	.0984"		M3x.5 coarse	
2.5273mm	.0995"	#39		
2.5781mm	.1015"	#38	#5-40 UNC	
2.6416mm	.104"	#37	#5-44 UNF	
2.7051mm	.1065"	#36	#6-32 UNC	
2.7781mm	.109375"	7/64"	#3 Wood Shank Hole #4 Wood Shank Hole #9 Pilot, Hard-wood #10 Pilot, Hard-wood #12 Pilot, Soft-wood #14 Pilot, Soft-wood	
2.794mm	.11"	#35		
2.8194mm	.111"	#34		
2.8702mm	.113"	#33	#6-40 UNF	
2.9mm	.1142"		M3.5x.6 coarse	
2.9464mm	.116"	#32		
3mm	.1181"			
3.048mm	.12"	#31		
3.175mm	.125"	1/8"	#5 Wood Shank Hole #11 Pilot, Hard-wood #12 Pilot, Hard-wood	
3.2639mm	.1285"	#30		
3.3mm	.1299"		M4x.7 coarse	
3.4544mm	.136"	#29	#8-32 UNC #8-36 UNF	
3.5mm	.1378"		M4x.5 Fine	
3.5687mm	.1405"	#28		
3.5719mm	.140625"	9/64"	#6 Wood Shank Hole #14 Pilot, Hard-wood #16 Pilot, Soft-wood #18 Pilot, Soft-wood	
3.6mm	.1417"		M4x.35 Fine	
3.6576mm	.144"	#27		
3.7mm	.1457"		M4.5x.75 coarse	
3.7338mm	.147"	#26		
3.7973mm	.1495"	#25	#10-24 UNC	
3.8608mm	.152"	#24		
3.9116mm	.154"	#23		
3.9688mm	.15625"	5/32"	#7 Wood Shank Hole #16 Pilot, Hard-wood	
3.9878mm	.157"	#22		
4mm	.1575"			
4.0386mm	.159"	#21	#10-32 UNF	
4.0894mm	.161"	#20		
4.2mm	.1654"		M5x.8 coarse	
4.2164mm	.166"	#19		
4.3053mm	.1695"	#18		
4.3656mm	.171875"	11/64"	#8 Wood Shank Hole #20 Pilot, Soft-wood	
4.3942mm	.173"	#17	#12-24 UNC	
4.4958mm	.177"	#16		
4.5mm	.1772"		M5x.5 Fine	
4.572mm	.18"	#15	#12-28 UNF	
4.6228mm	.182"	#14		
4.699mm	.185"	#13		
4.7625mm	.1875"	3/16"	#9 Wood Shank Hole #10 Wood Shank Hole #18 Pilot, Hard-wood	
4.8006mm	.189"	#12		
4.8514mm	.191"	#11		
4.9149mm	.1935"	#10		
4.9784mm	.196"	# 9		
5mm	.1969"		M6x1 coarse	
5.0546mm	.199"	# 8		
5.1054mm	.201"	# 7	¼"-20 UNC	
5.1594mm	.203125"	13/64"	#11 Wood Shank Hole #20 Pilot, Hard-wood	
5.1816mm	.204"	# 6		
5.2197mm	.2055"	# 5		
5.25mm	.2067"		M6x.75 Fine	
5.3086mm	.209"	# 4		
5.4102mm	.213"	# 3	¼"-28 UNF	
5.5mm	.2165"		M6x.5 Fine	
5.5563mm	.21875"	7/32"	#12 Wood Shank Hole	
5.6134mm	.221"	# 2		
5.7912mm	.228"	# 1		
5.9436mm	.234"	A		
5.9531mm	.234375"	15/64"		
6mm	.2362"		M7x1 coarse	
6.0452mm	.238"	B		
6.1468mm	.242"	C		
6.2484mm	.246"	D	1/16"-27 NPT	
6.25mm	.2461"		M7x.75 Fine	
6.35mm	.25"	1/4"	#14 Wood Shank Hole	
6.35mm	.25"	E		
6.5mm	.2559"			
6.5278mm	.257"	F	5/16"-18 UNC	
6.6294mm	.261"	G		
6.7469mm	.265625"	17/64"	#16 Wood Shank Hole	
6.7564mm	.266"	H		
6.8mm	.2677"		M8x1.25 coarse	
6.9088mm	.272"	I	5/16"-24 UNF	
7mm	.2756"		M8x.5 Fine	
7.0358mm	.277"	J		
7.1374mm	.281"	K		
7.1438mm	.28125"	9/32"		
7.25mm	.2854"		M8x.75 Fine	
7.366mm	.29"	L		
7.493mm	.295"	M		
7.5mm	.2953"		M8x1 Fine	
7.5406mm	.296875"	19/64"	#18 Wood Shank Hole	
7.6708mm	.302"	N		
7.8mm	.3071"		M9x1.25 coarse	
7.9375mm	.3125"	5/16"	3/8"-16 UNC	
8mm	.315"		M9x1 Fine	
8.0264mm	.316"	O		
8.2042mm	.323"	P		
8.3344mm	.328125"	21/64"	#20 Wood Shank Hole	
8.4328mm	.332"	Q	3/8"-24 UNF	
8.5mm	.3346"		M10x1.5 coarse	
8.6106mm	.339"	R	1/8"-27 NPT	
8.7313mm	.34375"	11/32"		
8.8mm	.3465"		M10x1.25 Fine	
8.8392mm	.348"	S		
9mm	.3543"		M10x1 Fine	
9.0932mm	.358"	T	7/16"-14 UNC	
9.1281mm	.359375"	23/64"		
9.25mm	.3642"		M10x.75 Fine	
9.3472mm	.368"	U		
9.5mm	.374"		M11x1.5 coarse	
9.525mm	.375"	3/8"		
9.5758mm	.377"	V		
9.8044mm	.386"	W		
9.9219mm	.390625"	25/64"	7/16"-20 UNF	
10mm	.3937"		M11x1 Fine	
10.0838mm	.397"	X		
10.2mm	.4016"		M12x1.75 coarse	
10.2616mm	.404"	Y		
10.3188mm	.40625"	13/32"		
10.4902mm	.413"	Z		
10.5mm	.4134"		M12x1.5 Fine	
10.7156mm	.421875"	27/64"	½"-13 UNC	
11mm	.4331"		M12x1 Fine	
11.1125mm	.4375"	7/16"	¼"-18 NPT	
11.25mm	.4429"		M12x.75 Fine	
11.5mm	.4528"			
11.5094mm	.453125"	29/64"	½"-20 UNF	
11.9063mm	.46875"	15/32"		
12mm	.4724"		M14x2 coarse	
12.3031mm	.484375"	31/64"	9/16"-12 UNC	
12.5mm	.4921"		M14x1.5 Fine	
12.7mm	.5"	1/2"		
12.8mm	.5039"		M14x1.25 Fine	
13mm	.5118"		M14x1 Fine	
13.0969mm	.515625"	33/64"	9/16"-18 UNF	
13.4938mm	.53125"	17/32"	5/8"-11 UNC	
13.5mm	.5315"			
13.8906mm	.546875"	35/64"		
14mm	.5512"		M16x2 coarse	
14.2875mm	.5625"	9/16"	5/8"-18 UNF	
14.5mm	.5709"		M16x1.5 Fine	
14.6844mm	.578125"	37/64"	3/8"-18 NPT	
15mm	.5906"		M16x1 Fine	
15.0813mm	.59375"	19/32"		
15.4781mm	.609375"	39/64"		
15.5mm	.6102"		M18x2.5 coarse	
15.875mm	.625"	5/8"		
16mm	.6299"		M18x2 Fine	
16.2719mm	.640625"	41/64"	¾"-10 UNC	
16.5mm	.6496"			
16.6688mm	.65625"	21/32"		
17mm	.6693"		M18x1 Fine	
17.0656mm	.671875"	43/64"		
17.4625mm	.6875"	11/16"	¾"-16 UNF	
17.5mm	.689"		M20x2.5 coarse	
17.8594mm	.703125"	45/64"	½"-14 NPT	
18mm	.7087"		M20x2 Fine	
18.2563mm	.71875"	23/32"		
18.5mm	.7283"		M20x1.5 Fine	
18.6531mm	.734375"	47/64"		
19mm	.748"		M20x1 Fine	
19.05mm	.75"	3/4"		
19.4469mm	.765625"	49/64"	7/8"-9 UNC	
19.5mm	.7677"		M22x2.5 coarse	
19.8438mm	.78125"	25/32"		
20mm	.7874"		M22x2 Fine	
20.2406mm	.796875"	51/64"		
20.5mm	.8071"		M22x1.5 Fine	
20.6375mm	.8125"	13/16"	7/8"-14 UNF	
21mm	.8268"		M24x3 coarse M22x1 Fine	
21.0344mm	.828125"	53/64"		
21.4313mm	.84375"	27/32"		
21.5mm	.8465"			
21.8281mm	.859375"	55/64"		
22mm	.8661"		M24x2 Fine	
22.225mm	.875"	7/8"	1"-8 UNC	
22.5mm	.8858"		M24x1.5 Fine	
22.6219mm	.890625"	57/64"		
23mm	.9055"			
23.0188mm	.90625"	29/32"	1"-12 UNF	
23.4156mm	.921875"	59/64"	¾"-14 NPT	
23.5mm	.9252"			
23.8125mm	.9375"	15/16"		
24mm	.9449"		M27x3 coarse	
24.2094mm	.953125"	61/64"		
24.5mm	.9646"		M26x1.5 Fine	
24.6063mm	.96875"	31/32"		
25mm	.9843"		M27x2 Fine	
25.0031mm	.984375"	63/64"	1-1/8"-7 UNC	
25.4mm	1.000"	1"		
25.5mm	1.0039"		M27x1.5 Fine	
26.5mm	1.0433"		M30x3.5 coarse	
26.5mm	1.0433"		M28x1.5 Fine	
26.5906mm	1.046875"	1-3/64"	1-1/8"-12 UNF	
26.9875mm	1.0625"	1-1/16"		
28mm	1.1024"		M30x2 Fine	
28.1781mm	1.109375"	1-7/64"	1¼"-7 UNC	
28.5mm	1.122"		M30x1.5 Fine	
28.575mm	1.125"	1-1/8"		
29.3688mm	1.15625"	1-5/32"	1"-11½ NPT	
29.5mm	1.1614"		M33x3.5 coarse	
29.7656mm	1.171875"	1-11/64"	1¼"-12 UNF	
30.1625mm	1.1875"	1-3/16"		
31mm	1.2205"		M33x2 Fine	
32mm	1.2598"		M36x4 coarse	
33mm	1.2992"		M36x3 Fine	
34.1313mm	1.34375"	1-11/32"	1½"-6 UNC	
34.925mm	1.375"	1-3/8"		
35mm	1.378"		M39x4 coarse	
36mm	1.4173"		M39x3 Fine	
36.1156mm	1.421875"	1-27/64"	1½"-12 UNF	
36.5125mm	1.4375"	1-7/16"		
38.1mm	1.5"	1½"	1¼"-11½ NPT	
39.2906mm	1.546875"	1-35/64"	1¾"-5 UNC	
39.6875mm	1.5625"	1-9/16"		
41.275mm	1.625"	1-5/8"		
42.4656mm	1.671875"	1-43/64"	1¾"-12 UNF	
44.0531mm	1.734375"	1-47/64"	1½"-11½ NPT	
44.45mm	1.75"	1-3/4"		
45.2438mm	1.78125"	1-25/32"	2"-4½ UNC	
46.0375mm	1.8125"	1-13/16"		
47.625mm	1.875"	1-7/8"		
48.8156mm	1.921875"	1-59/64"	2"-12 UNF	
49.2125mm	1.9375"	1-15/16"		
56.3563mm	2.21875"	2-7/32"	2"-11½ NPT	
66.675mm	2.625"	2-5/8"	2½-8 NPT	
82.55mm	3.25"	3¼"	3"-8 NPT	
88.9mm	3.5"	3¾"	3½"-8 NPT	
107.95mm	4.25"	4¼	4"-8 NPT	

Legend 				
Fractional Inch				
Letter Drill				
Millimeters				
Number Drill				
Millimeters 	Inches 	Designation 	Tap Drill/Pilot 	
.3429mm	.0135"	#80		
.3683mm	.0145"	#79		
.3969mm	.015625"	1/64"	#0 Pilot, Soft-Wood	
.4064mm	.016"	#78		
.4572mm	.018"	#77		
.5mm	.0197"			
.508mm	.02"	#76		
.5334mm	.021"	#75		
.5715mm	.0225"	#74		
.6096mm	.024"	#73		
.635mm	.025"	#72		
.6604mm	.026"	#71		
.7112mm	.028"	#70		
.74168mm	.0292"	#69		
.75mm	.0295"		M1x.25 coarse	
.7874mm	.031"	#68		
.7938mm	.03125"	1/32"	#0 Pilot, Hard-Wood #1 Pilot, Hard & Soft-Wood #2 Pilot, Soft-Wood	
.8128mm	.032"	#67		
.8382mm	.033"	#66		
.85mm	.0335"		M1.1x.25 coarse	
.889mm	.035"	#65		
.9144mm	.036"	#64		
.9398mm	.037"	#63		
.95mm	.0374"		M1.2x.25 coarse	
.9652mm	.038"	#62		
.9906mm	.039"	#61		
1mm	.0394"			
1.016mm	.04"	#60		
1.0414mm	.041"	#59		
1.0668mm	.042"	#58		
1.0922mm	.043"	#57		
1.1mm	.0433"		M1.4x.3 coarse	
1.1811mm	.0465"	#56		
1.1906mm	.046875"	3/64"	#0-80 UNF #2 Pilot, Hard-wood #3 Pilot, Soft-Wood #4 Pilot, Soft-Wood	
1.25mm	.0492"		M1.6x.35 coarse	
1.3mm	.0512"		M1.7x.35 coarse	
1.3208mm	.052"	#55		
1.397mm	.055"	#54		
1.45mm	.0571"		M1.8x.35 coarse	
1.5mm	.0591"			
1.5113mm	.0595"	#53	#1-64 UNC #1-72 UNF	
1.5875mm	.0625"	1/16"	#0 Wood Shank Hole #3 Pilot, Hard-Wood #4 Pilot, Hard-wood #5 Pilot, Soft-wood #6 Pilot, Soft-wood #7 Pilot, Soft-wood	
1.6mm	.063"		M2x.4 coarse	
1.6129mm	.0635"	#52		
1.7018mm	.067"	#51		
1.75mm	.0689"		M2.2x.45 coarse	
1.778mm	.07"	#50	#2-64 UNF #2-56 UNC	
1.8542mm	.073"	#49		
1.9304mm	.076"	#48		
1.9844mm	.078125"	5/64"	#1 Wood Shank Hole #5 Pilot, Hard-wood #6 Pilot, Hard-wood #8 Pilot, Soft-wood #9 Pilot, Soft-wood	
1.9939mm	.0785"	#47	#3-48 UNC	
2mm	.0787"			
2.05mm	.0807"		M2.5x.45 coarse	
2.0574mm	.081"	#46		
2.0828mm	.082"	#45	#3-56 UNF	
2.1844mm	.086"	#44		
2.2606mm	.089"	#43	#4-40 UNC	
2.3749mm	.0935"	#42	#4-48 UNF	
2.3813mm	.09375"	3/32"	#2 Wood Shank Hole #7 Pilot, Hard-wood #8 Pilot, Hard-wood #10 Pilot, Soft-wood #11 Pilot, Soft-wood	
2.4384mm	.096"	#41		
2.4892mm	.098"	#40		
2.5mm	.0984"		M3x.5 coarse	
2.5273mm	.0995"	#39		
2.5781mm	.1015"	#38	#5-40 UNC	
2.6416mm	.104"	#37	#5-44 UNF	
2.7051mm	.1065"	#36	#6-32 UNC	
2.7781mm	.109375"	7/64"	#3 Wood Shank Hole #4 Wood Shank Hole #9 Pilot, Hard-wood #10 Pilot, Hard-wood #12 Pilot, Soft-wood #14 Pilot, Soft-wood	
2.794mm	.11"	#35		
2.8194mm	.111"	#34		
2.8702mm	.113"	#33	#6-40 UNF	
2.9mm	.1142"		M3.5x.6 coarse	
2.9464mm	.116"	#32		
3mm	.1181"			
3.048mm	.12"	#31		
3.175mm	.125"	1/8"	#5 Wood Shank Hole #11 Pilot, Hard-wood #12 Pilot, Hard-wood	
3.2639mm	.1285"	#30		
3.3mm	.1299"		M4x.7 coarse	
3.4544mm	.136"	#29	#8-32 UNC #8-36 UNF	
3.5mm	.1378"		M4x.5 Fine	
3.5687mm	.1405"	#28		
3.5719mm	.140625"	9/64"	#6 Wood Shank Hole #14 Pilot, Hard-wood #16 Pilot, Soft-wood #18 Pilot, Soft-wood	
3.6mm	.1417"		M4x.35 Fine	
3.6576mm	.144"	#27		
3.7mm	.1457"		M4.5x.75 coarse	
3.7338mm	.147"	#26		
3.7973mm	.1495"	#25	#10-24 UNC	
3.8608mm	.152"	#24		
3.9116mm	.154"	#23		
3.9688mm	.15625"	5/32"	#7 Wood Shank Hole #16 Pilot, Hard-wood	
3.9878mm	.157"	#22		
4mm	.1575"			
4.0386mm	.159"	#21	#10-32 UNF	
4.0894mm	.161"	#20		
4.2mm	.1654"		M5x.8 coarse	
4.2164mm	.166"	#19		
4.3053mm	.1695"	#18		
4.3656mm	.171875"	11/64"	#8 Wood Shank Hole #20 Pilot, Soft-wood	
4.3942mm	.173"	#17	#12-24 UNC	
4.4958mm	.177"	#16		
4.5mm	.1772"		M5x.5 Fine	
4.572mm	.18"	#15	#12-28 UNF	
4.6228mm	.182"	#14		
4.699mm	.185"	#13		
4.7625mm	.1875"	3/16"	#9 Wood Shank Hole #10 Wood Shank Hole #18 Pilot, Hard-wood	
4.8006mm	.189"	#12		
4.8514mm	.191"	#11		
4.9149mm	.1935"	#10		
4.9784mm	.196"	# 9		
5mm	.1969"		M6x1 coarse	
5.0546mm	.199"	# 8		
5.1054mm	.201"	# 7	¼"-20 UNC	
5.1594mm	.203125"	13/64"	#11 Wood Shank Hole #20 Pilot, Hard-wood	
5.1816mm	.204"	# 6		
5.2197mm	.2055"	# 5		
5.25mm	.2067"		M6x.75 Fine	
5.3086mm	.209"	# 4		
5.4102mm	.213"	# 3	¼"-28 UNF	
5.5mm	.2165"		M6x.5 Fine	
5.5563mm	.21875"	7/32"	#12 Wood Shank Hole	
5.6134mm	.221"	# 2		
5.7912mm	.228"	# 1		
5.9436mm	.234"	A		
5.9531mm	.234375"	15/64"		
6mm	.2362"		M7x1 coarse	
6.0452mm	.238"	B		
6.1468mm	.242"	C		
6.2484mm	.246"	D	1/16"-27 NPT	
6.25mm	.2461"		M7x.75 Fine	
6.35mm	.25"	1/4"	#14 Wood Shank Hole	
6.35mm	.25"	E		
6.5mm	.2559"			
6.5278mm	.257"	F	5/16"-18 UNC	
6.6294mm	.261"	G		
6.7469mm	.265625"	17/64"	#16 Wood Shank Hole	
6.7564mm	.266"	H		
6.8mm	.2677"		M8x1.25 coarse	
6.9088mm	.272"	I	5/16"-24 UNF	
7mm	.2756"		M8x.5 Fine	
7.0358mm	.277"	J		
7.1374mm	.281"	K		
7.1438mm	.28125"	9/32"		
7.25mm	.2854"		M8x.75 Fine	
7.366mm	.29"	L		
7.493mm	.295"	M		
7.5mm	.2953"		M8x1 Fine	
7.5406mm	.296875"	19/64"	#18 Wood Shank Hole	
7.6708mm	.302"	N		
7.8mm	.3071"		M9x1.25 coarse	
7.9375mm	.3125"	5/16"	3/8"-16 UNC	
8mm	.315"		M9x1 Fine	
8.0264mm	.316"	O		
8.2042mm	.323"	P		
8.3344mm	.328125"	21/64"	#20 Wood Shank Hole	
8.4328mm	.332"	Q	3/8"-24 UNF	
8.5mm	.3346"		M10x1.5 coarse	
8.6106mm	.339"	R	1/8"-27 NPT	
8.7313mm	.34375"	11/32"		
8.8mm	.3465"		M10x1.25 Fine	
8.8392mm	.348"	S		
9mm	.3543"		M10x1 Fine	
9.0932mm	.358"	T	7/16"-14 UNC	
9.1281mm	.359375"	23/64"		
9.25mm	.3642"		M10x.75 Fine	
9.3472mm	.368"	U		
9.5mm	.374"		M11x1.5 coarse	
9.525mm	.375"	3/8"		
9.5758mm	.377"	V		
9.8044mm	.386"	W		
9.9219mm	.390625"	25/64"	7/16"-20 UNF	
10mm	.3937"		M11x1 Fine	
10.0838mm	.397"	X		
10.2mm	.4016"		M12x1.75 coarse	
10.2616mm	.404"	Y		
10.3188mm	.40625"	13/32"		
10.4902mm	.413"	Z		
10.5mm	.4134"		M12x1.5 Fine	
10.7156mm	.421875"	27/64"	½"-13 UNC	
11mm	.4331"		M12x1 Fine	
11.1125mm	.4375"	7/16"	¼"-18 NPT	
11.25mm	.4429"		M12x.75 Fine	
11.5mm	.4528"			
11.5094mm	.453125"	29/64"	½"-20 UNF	
11.9063mm	.46875"	15/32"		
12mm	.4724"		M14x2 coarse	
12.3031mm	.484375"	31/64"	9/16"-12 UNC	
12.5mm	.4921"		M14x1.5 Fine	
12.7mm	.5"	1/2"		
12.8mm	.5039"		M14x1.25 Fine	
13mm	.5118"		M14x1 Fine	
13.0969mm	.515625"	33/64"	9/16"-18 UNF	
13.4938mm	.53125"	17/32"	5/8"-11 UNC	
13.5mm	.5315"			
13.8906mm	.546875"	35/64"		
14mm	.5512"		M16x2 coarse	
14.2875mm	.5625"	9/16"	5/8"-18 UNF	
14.5mm	.5709"		M16x1.5 Fine	
14.6844mm	.578125"	37/64"	3/8"-18 NPT	
15mm	.5906"		M16x1 Fine	
15.0813mm	.59375"	19/32"		
15.4781mm	.609375"	39/64"		
15.5mm	.6102"		M18x2.5 coarse	
15.875mm	.625"	5/8"		
16mm	.6299"		M18x2 Fine	
16.2719mm	.640625"	41/64"	¾"-10 UNC	
16.5mm	.6496"			
16.6688mm	.65625"	21/32"		
17mm	.6693"		M18x1 Fine	
17.0656mm	.671875"	43/64"		
17.4625mm	.6875"	11/16"	¾"-16 UNF	
17.5mm	.689"		M20x2.5 coarse	
17.8594mm	.703125"	45/64"	½"-14 NPT	
18mm	.7087"		M20x2 Fine	
18.2563mm	.71875"	23/32"		
18.5mm	.7283"		M20x1.5 Fine	
18.6531mm	.734375"	47/64"		
19mm	.748"		M20x1 Fine	
19.05mm	.75"	3/4"		
19.4469mm	.765625"	49/64"	7/8"-9 UNC	
19.5mm	.7677"		M22x2.5 coarse	
19.8438mm	.78125"	25/32"		
20mm	.7874"		M22x2 Fine	
20.2406mm	.796875"	51/64"		
20.5mm	.8071"		M22x1.5 Fine	
20.6375mm	.8125"	13/16"	7/8"-14 UNF	
21mm	.8268"		M24x3 coarse M22x1 Fine	
21.0344mm	.828125"	53/64"		
21.4313mm	.84375"	27/32"		
21.5mm	.8465"			
21.8281mm	.859375"	55/64"		
22mm	.8661"		M24x2 Fine	
22.225mm	.875"	7/8"	1"-8 UNC	
22.5mm	.8858"		M24x1.5 Fine	
22.6219mm	.890625"	57/64"		
23mm	.9055"			
23.0188mm	.90625"	29/32"	1"-12 UNF	
23.4156mm	.921875"	59/64"	¾"-14 NPT	
23.5mm	.9252"			
23.8125mm	.9375"	15/16"		
24mm	.9449"		M27x3 coarse	
24.2094mm	.953125"	61/64"		
24.5mm	.9646"		M26x1.5 Fine	
24.6063mm	.96875"	31/32"		
25mm	.9843"		M27x2 Fine	
25.0031mm	.984375"	63/64"	1-1/8"-7 UNC	
25.4mm	1.000"	1"		
25.5mm	1.0039"		M27x1.5 Fine	
26.5mm	1.0433"		M30x3.5 coarse	
26.5mm	1.0433"		M28x1.5 Fine	
26.5906mm	1.046875"	1-3/64"	1-1/8"-12 UNF	
26.9875mm	1.0625"	1-1/16"		
28mm	1.1024"		M30x2 Fine	
28.1781mm	1.109375"	1-7/64"	1¼"-7 UNC	
28.5mm	1.122"		M30x1.5 Fine	
28.575mm	1.125"	1-1/8"		
29.3688mm	1.15625"	1-5/32"	1"-11½ NPT	
29.5mm	1.1614"		M33x3.5 coarse	
29.7656mm	1.171875"	1-11/64"	1¼"-12 UNF	
30.1625mm	1.1875"	1-3/16"		
31mm	1.2205"		M33x2 Fine	
32mm	1.2598"		M36x4 coarse	
33mm	1.2992"		M36x3 Fine	
34.1313mm	1.34375"	1-11/32"	1½"-6 UNC	
34.925mm	1.375"	1-3/8"		
35mm	1.378"		M39x4 coarse	
36mm	1.4173"		M39x3 Fine	
36.1156mm	1.421875"	1-27/64"	1½"-12 UNF	
36.5125mm	1.4375"	1-7/16"		
38.1mm	1.5"	1½"	1¼"-11½ NPT	
39.2906mm	1.546875"	1-35/64"	1¾"-5 UNC	
39.6875mm	1.5625"	1-9/16"		
41.275mm	1.625"	1-5/8"		
42.4656mm	1.671875"	1-43/64"	1¾"-12 UNF	
44.0531mm	1.734375"	1-47/64"	1½"-11½ NPT	
44.45mm	1.75"	1-3/4"		
45.2438mm	1.78125"	1-25/32"	2"-4½ UNC	
46.0375mm	1.8125"	1-13/16"		
47.625mm	1.875"	1-7/8"		
48.8156mm	1.921875"	1-59/64"	2"-12 UNF	
49.2125mm	1.9375"	1-15/16"		
56.3563mm	2.21875"	2-7/32"	2"-11½ NPT	
66.675mm	2.625"	2-5/8"	2½-8 NPT	
82.55mm	3.25"	3¼"	3"-8 NPT	
88.9mm	3.5"	3¾"	3½"-8 NPT	
107.95mm	4.25"	4¼	4"-8 NPT	

Legend 				
Fractional Inch				
Letter Drill				
Millimeters				
Number Drill				
Millimeters 	Inches 	Designation 	Tap Drill/Pilot 	
.3429mm	.0135"	#80		
.3683mm	.0145"	#79		
.3969mm	.015625"	1/64"	#0 Pilot, Soft-Wood	
.4064mm	.016"	#78		
.4572mm	.018"	#77		
.5mm	.0197"			
.508mm	.02"	#76		
.5334mm	.021"	#75		
.5715mm	.0225"	#74		
.6096mm	.024"	#73		
.635mm	.025"	#72		
.6604mm	.026"	#71		
.7112mm	.028"	#70		
.74168mm	.0292"	#69		
.75mm	.0295"		M1x.25 coarse	
.7874mm	.031"	#68		
.7938mm	.03125"	1/32"	#0 Pilot, Hard-Wood #1 Pilot, Hard & Soft-Wood #2 Pilot, Soft-Wood	
.8128mm	.032"	#67		
.8382mm	.033"	#66		
.85mm	.0335"		M1.1x.25 coarse	
.889mm	.035"	#65		
.9144mm	.036"	#64		
.9398mm	.037"	#63		
.95mm	.0374"		M1.2x.25 coarse	
.9652mm	.038"	#62		
.9906mm	.039"	#61		
1mm	.0394"			
1.016mm	.04"	#60		
1.0414mm	.041"	#59		
1.0668mm	.042"	#58		
1.0922mm	.043"	#57		
1.1mm	.0433"		M1.4x.3 coarse	
1.1811mm	.0465"	#56		
1.1906mm	.046875"	3/64"	#0-80 UNF #2 Pilot, Hard-wood #3 Pilot, Soft-Wood #4 Pilot, Soft-Wood	
1.25mm	.0492"		M1.6x.35 coarse	
1.3mm	.0512"		M1.7x.35 coarse	
1.3208mm	.052"	#55		
1.397mm	.055"	#54		
1.45mm	.0571"		M1.8x.35 coarse	
1.5mm	.0591"			
1.5113mm	.0595"	#53	#1-64 UNC #1-72 UNF	
1.5875mm	.0625"	1/16"	#0 Wood Shank Hole #3 Pilot, Hard-Wood #4 Pilot, Hard-wood #5 Pilot, Soft-wood #6 Pilot, Soft-wood #7 Pilot, Soft-wood	
1.6mm	.063"		M2x.4 coarse	
1.6129mm	.0635"	#52		
1.7018mm	.067"	#51		
1.75mm	.0689"		M2.2x.45 coarse	
1.778mm	.07"	#50	#2-64 UNF #2-56 UNC	
1.8542mm	.073"	#49		
1.9304mm	.076"	#48		
1.9844mm	.078125"	5/64"	#1 Wood Shank Hole #5 Pilot, Hard-wood #6 Pilot, Hard-wood #8 Pilot, Soft-wood #9 Pilot, Soft-wood	
1.9939mm	.0785"	#47	#3-48 UNC	
2mm	.0787"			
2.05mm	.0807"		M2.5x.45 coarse	
2.0574mm	.081"	#46		
2.0828mm	.082"	#45	#3-56 UNF	
2.1844mm	.086"	#44		
2.2606mm	.089"	#43	#4-40 UNC	
2.3749mm	.0935"	#42	#4-48 UNF	
2.3813mm	.09375"	3/32"	#2 Wood Shank Hole #7 Pilot, Hard-wood #8 Pilot, Hard-wood #10 Pilot, Soft-wood #11 Pilot, Soft-wood	
2.4384mm	.096"	#41		
2.4892mm	.098"	#40		
2.5mm	.0984"		M3x.5 coarse	
2.5273mm	.0995"	#39		
2.5781mm	.1015"	#38	#5-40 UNC	
2.6416mm	.104"	#37	#5-44 UNF	
2.7051mm	.1065"	#36	#6-32 UNC	
2.7781mm	.109375"	7/64"	#3 Wood Shank Hole #4 Wood Shank Hole #9 Pilot, Hard-wood #10 Pilot, Hard-wood #12 Pilot, Soft-wood #14 Pilot, Soft-wood	
2.794mm	.11"	#35		
2.8194mm	.111"	#34		
2.8702mm	.113"	#33	#6-40 UNF	
2.9mm	.1142"		M3.5x.6 coarse	
2.9464mm	.116"	#32		
3mm	.1181"			
3.048mm	.12"	#31		
3.175mm	.125"	1/8"	#5 Wood Shank Hole #11 Pilot, Hard-wood #12 Pilot, Hard-wood	
3.2639mm	.1285"	#30		
3.3mm	.1299"		M4x.7 coarse	
3.4544mm	.136"	#29	#8-32 UNC #8-36 UNF	
3.5mm	.1378"		M4x.5 Fine	
3.5687mm	.1405"	#28		
3.5719mm	.140625"	9/64"	#6 Wood Shank Hole #14 Pilot, Hard-wood #16 Pilot, Soft-wood #18 Pilot, Soft-wood	
3.6mm	.1417"		M4x.35 Fine	
3.6576mm	.144"	#27		
3.7mm	.1457"		M4.5x.75 coarse	
3.7338mm	.147"	#26		
3.7973mm	.1495"	#25	#10-24 UNC	
3.8608mm	.152"	#24		
3.9116mm	.154"	#23		
3.9688mm	.15625"	5/32"	#7 Wood Shank Hole #16 Pilot, Hard-wood	
3.9878mm	.157"	#22		
4mm	.1575"			
4.0386mm	.159"	#21	#10-32 UNF	
4.0894mm	.161"	#20		
4.2mm	.1654"		M5x.8 coarse	
4.2164mm	.166"	#19		
4.3053mm	.1695"	#18		
4.3656mm	.171875"	11/64"	#8 Wood Shank Hole #20 Pilot, Soft-wood	
4.3942mm	.173"	#17	#12-24 UNC	
4.4958mm	.177"	#16		
4.5mm	.1772"		M5x.5 Fine	
4.572mm	.18"	#15	#12-28 UNF	
4.6228mm	.182"	#14		
4.699mm	.185"	#13		
4.7625mm	.1875"	3/16"	#9 Wood Shank Hole #10 Wood Shank Hole #18 Pilot, Hard-wood	
4.8006mm	.189"	#12		
4.8514mm	.191"	#11		
4.9149mm	.1935"	#10		
4.9784mm	.196"	# 9		
5mm	.1969"		M6x1 coarse	
5.0546mm	.199"	# 8		
5.1054mm	.201"	# 7	¼"-20 UNC	
5.1594mm	.203125"	13/64"	#11 Wood Shank Hole #20 Pilot, Hard-wood	
5.1816mm	.204"	# 6		
5.2197mm	.2055"	# 5		
5.25mm	.2067"		M6x.75 Fine	
5.3086mm	.209"	# 4		
5.4102mm	.213"	# 3	¼"-28 UNF	
5.5mm	.2165"		M6x.5 Fine	
5.5563mm	.21875"	7/32"	#12 Wood Shank Hole	
5.6134mm	.221"	# 2		
5.7912mm	.228"	# 1		
5.9436mm	.234"	A		
5.9531mm	.234375"	15/64"		
6mm	.2362"		M7x1 coarse	
6.0452mm	.238"	B		
6.1468mm	.242"	C		
6.2484mm	.246"	D	1/16"-27 NPT	
6.25mm	.2461"		M7x.75 Fine	
6.35mm	.25"	1/4"	#14 Wood Shank Hole	
6.35mm	.25"	E		
6.5mm	.2559"			
6.5278mm	.257"	F	5/16"-18 UNC	
6.6294mm	.261"	G		
6.7469mm	.265625"	17/64"	#16 Wood Shank Hole	
6.7564mm	.266"	H		
6.8mm	.2677"		M8x1.25 coarse	
6.9088mm	.272"	I	5/16"-24 UNF	
7mm	.2756"		M8x.5 Fine	
7.0358mm	.277"	J		
7.1374mm	.281"	K		
7.1438mm	.28125"	9/32"		
7.25mm	.2854"		M8x.75 Fine	
7.366mm	.29"	L		
7.493mm	.295"	M		
7.5mm	.2953"		M8x1 Fine	
7.5406mm	.296875"	19/64"	#18 Wood Shank Hole	
7.6708mm	.302"	N		
7.8mm	.3071"		M9x1.25 coarse	
7.9375mm	.3125"	5/16"	3/8"-16 UNC	
8mm	.315"		M9x1 Fine	
8.0264mm	.316"	O		
8.2042mm	.323"	P		
8.3344mm	.328125"	21/64"	#20 Wood Shank Hole	
8.4328mm	.332"	Q	3/8"-24 UNF	
8.5mm	.3346"		M10x1.5 coarse	
8.6106mm	.339"	R	1/8"-27 NPT	
8.7313mm	.34375"	11/32"		
8.8mm	.3465"		M10x1.25 Fine	
8.8392mm	.348"	S		
9mm	.3543"		M10x1 Fine	
9.0932mm	.358"	T	7/16"-14 UNC	
9.1281mm	.359375"	23/64"		
9.25mm	.3642"		M10x.75 Fine	
9.3472mm	.368"	U		
9.5mm	.374"		M11x1.5 coarse	
9.525mm	.375"	3/8"		
9.5758mm	.377"	V		
9.8044mm	.386"	W		
9.9219mm	.390625"	25/64"	7/16"-20 UNF	
10mm	.3937"		M11x1 Fine	
10.0838mm	.397"	X		
10.2mm	.4016"		M12x1.75 coarse	
10.2616mm	.404"	Y		
10.3188mm	.40625"	13/32"		
10.4902mm	.413"	Z		
10.5mm	.4134"		M12x1.5 Fine	
10.7156mm	.421875"	27/64"	½"-13 UNC	
11mm	.4331"		M12x1 Fine	
11.1125mm	.4375"	7/16"	¼"-18 NPT	
11.25mm	.4429"		M12x.75 Fine	
11.5mm	.4528"			
11.5094mm	.453125"	29/64"	½"-20 UNF	
11.9063mm	.46875"	15/32"		
12mm	.4724"		M14x2 coarse	
12.3031mm	.484375"	31/64"	9/16"-12 UNC	
12.5mm	.4921"		M14x1.5 Fine	
12.7mm	.5"	1/2"		
12.8mm	.5039"		M14x1.25 Fine	
13mm	.5118"		M14x1 Fine	
13.0969mm	.515625"	33/64"	9/16"-18 UNF	
13.4938mm	.53125"	17/32"	5/8"-11 UNC	
13.5mm	.5315"			
13.8906mm	.546875"	35/64"		
14mm	.5512"		M16x2 coarse	
14.2875mm	.5625"	9/16"	5/8"-18 UNF	
14.5mm	.5709"		M16x1.5 Fine	
14.6844mm	.578125"	37/64"	3/8"-18 NPT	
15mm	.5906"		M16x1 Fine	
15.0813mm	.59375"	19/32"		
15.4781mm	.609375"	39/64"		
15.5mm	.6102"		M18x2.5 coarse	
15.875mm	.625"	5/8"		
16mm	.6299"		M18x2 Fine	
16.2719mm	.640625"	41/64"	¾"-10 UNC	
16.5mm	.6496"			
16.6688mm	.65625"	21/32"		
17mm	.6693"		M18x1 Fine	
17.0656mm	.671875"	43/64"		
17.4625mm	.6875"	11/16"	¾"-16 UNF	
17.5mm	.689"		M20x2.5 coarse	
17.8594mm	.703125"	45/64"	½"-14 NPT	
18mm	.7087"		M20x2 Fine	
18.2563mm	.71875"	23/32"		
18.5mm	.7283"		M20x1.5 Fine	
18.6531mm	.734375"	47/64"		
19mm	.748"		M20x1 Fine	
19.05mm	.75"	3/4"		
19.4469mm	.765625"	49/64"	7/8"-9 UNC	
19.5mm	.7677"		M22x2.5 coarse	
19.8438mm	.78125"	25/32"		
20mm	.7874"		M22x2 Fine	
20.2406mm	.796875"	51/64"		
20.5mm	.8071"		M22x1.5 Fine	
20.6375mm	.8125"	13/16"	7/8"-14 UNF	
21mm	.8268"		M24x3 coarse M22x1 Fine	
21.0344mm	.828125"	53/64"		
21.4313mm	.84375"	27/32"		
21.5mm	.8465"			
21.8281mm	.859375"	55/64"		
22mm	.8661"		M24x2 Fine	
22.225mm	.875"	7/8"	1"-8 UNC	
22.5mm	.8858"		M24x1.5 Fine	
22.6219mm	.890625"	57/64"		
23mm	.9055"			
23.0188mm	.90625"	29/32"	1"-12 UNF	
23.4156mm	.921875"	59/64"	¾"-14 NPT	
23.5mm	.9252"			
23.8125mm	.9375"	15/16"		
24mm	.9449"		M27x3 coarse	
24.2094mm	.953125"	61/64"		
24.5mm	.9646"		M26x1.5 Fine	
24.6063mm	.96875"	31/32"		
25mm	.9843"		M27x2 Fine	
25.0031mm	.984375"	63/64"	1-1/8"-7 UNC	
25.4mm	1.000"	1"		
25.5mm	1.0039"		M27x1.5 Fine	
26.5mm	1.0433"		M30x3.5 coarse	
26.5mm	1.0433"		M28x1.5 Fine	
26.5906mm	1.046875"	1-3/64"	1-1/8"-12 UNF	
26.9875mm	1.0625"	1-1/16"		
28mm	1.1024"		M30x2 Fine	
28.1781mm	1.109375"	1-7/64"	1¼"-7 UNC	
28.5mm	1.122"		M30x1.5 Fine	
28.575mm	1.125"	1-1/8"		
29.3688mm	1.15625"	1-5/32"	1"-11½ NPT	
29.5mm	1.1614"		M33x3.5 coarse	
29.7656mm	1.171875"	1-11/64"	1¼"-12 UNF	
30.1625mm	1.1875"	1-3/16"		
31mm	1.2205"		M33x2 Fine	
32mm	1.2598"		M36x4 coarse	
33mm	1.2992"		M36x3 Fine	
34.1313mm	1.34375"	1-11/32"	1½"-6 UNC	
34.925mm	1.375"	1-3/8"		
35mm	1.378"		M39x4 coarse	
36mm	1.4173"		M39x3 Fine	
36.1156mm	1.421875"	1-27/64"	1½"-12 UNF	
36.5125mm	1.4375"	1-7/16"		
38.1mm	1.5"	1½"	1¼"-11½ NPT	
39.2906mm	1.546875"	1-35/64"	1¾"-5 UNC	
39.6875mm	1.5625"	1-9/16"		
41.275mm	1.625"	1-5/8"		
42.4656mm	1.671875"	1-43/64"	1¾"-12 UNF	
44.0531mm	1.734375"	1-47/64"	1½"-11½ NPT	
44.45mm	1.75"	1-3/4"		
45.2438mm	1.78125"	1-25/32"	2"-4½ UNC	
46.0375mm	1.8125"	1-13/16"		
47.625mm	1.875"	1-7/8"		
48.8156mm	1.921875"	1-59/64"	2"-12 UNF	
49.2125mm	1.9375"	1-15/16"		
56.3563mm	2.21875"	2-7/32"	2"-11½ NPT	
66.675mm	2.625"	2-5/8"	2½-8 NPT	
82.55mm	3.25"	3¼"	3"-8 NPT	
88.9mm	3.5"	3¾"	3½"-8 NPT	
107.95mm	4.25"	4¼	4"-8 NPT	

Tap Drill Size Chart for Standard Threads	

American Standard Thread		......	ISO Metric Thread		
Thread Size	Tap Drill Size (in.)		Thread Size	Tap Drill Size(mm)	
0-80	3/64		M1 x 0.25	0.75	
1-64	53		M1.1 x 0.25	0.85	
1-72	53		M1.2 x 0.25	0.95	
2-56	51		M1.4 x 0.3	1.10	
2-64	50		M1.6 x 0.35	1.25	
3-48	5/64		M1.8 x 0.35	1.45	
3-56	46		M2 x 0.4	1.60	
4-40	43		M2.2 x 0.45	1.75	
4-48	42		M2.5 x 0.45	2.05	
5-40	39		M3 x 0.5	2.50	

Thread Size	Tap Drill Size (in.)	......	Thread Size 	Tap Drill Size(mm)	
5-44	37		M3.5 x 0.6	2.90	
6-32	36		M4 x 0.7	3.30	
6-40	33		M4.5 x 0.75	3.70	
8-32	29		M5 x 0.8	4.20	
8-36	29		M6 x 1	5.00	
10-24	25		M7 x 1	6.00	
10-32	21		M8 x 1.25	6.80	
12-24	17		M9 x 1.25	7.80	
12-28	15		M10 x 1.5	8.50	
1/4-20	7		M11 x 1.5	9.50	

Thread Size	Tap Drill Size (in.)	......	Thread Size 	Tap Drill Size(mm)	
1/4-28	3		M12 x 1.75	10.20	
5/16-18	F		M14 x 2	12.00	
5/16-24	I		M16 x 2	14.00	
3/8-16	5/16		M18 x 2.5	15.50	
3/8-24	Q		M20 x 2.5	17.50	
7/16-14	U		M22 x 2.5	19.50	
7/16-20	W		M24 x 3	21.00	
1/2-13	27/64		M27 x 3 	24.00	
1/2-20	29/64		M30 x 3.5	26.50	
9/16-12	31/64		M33 x 3.5	29.50	

Thread Size	Tap Drill Size (in.)	......	Thread Size 	Tap Drill Size(mm)	
9/16-18	33/64		M36 x 4	32.00	
5/8-11	17/32		M39 x 4	35.00	
5/8-18	37/64		M42 x 4.5	37.50	
3/4-10	21/32		M45 x 4.5	40.50	
3/4-16	11/16		M48 x 5	43.00	
7/8-9	49/64		M52 x 5	47.00	
7/8-14	13/16		M56 x 5.5	50.50	
1"-8	7/8		M60 x 5.5	54.50	
1"-14	15/18		M64 x 6	58.00	
			M68 x 6	62.00