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Tap & Drill Chart UNC - UNIFIED NATIONAL COARSE
Size - Imperial
Threads Per Inch
TAPPING DRILL SIZE
Preferred
Alternative
mm
inch
mm
inch
#1
64
1.50
53
1.55
#2
56
1.85
50
1.80
#3
48
2.10
47
2.05
5/64
#4
40
2.35
3/32
2.30
43
#5
40
2.65
38
2.60
#6
32
2.85
36
2.80
7/64
#8
32
3.50
29
3.40
#10
24
3.90
25
3.00
5/32
#12
24
4.50
16
4.40
11/64
1/4
20
5.20
13/64
5.10
7
5/16
18
6.60
17/64
6.50
F
3/8
16
8.10
5/16
8.00
7/16
14
9.50
3/8
9.40
23/64
1/2
13
11.00
27/64
10.80
9/16
12
12.20
31/64
5/8
11
13.80
35/64
13.50
17/32
3/4
10
21/32
16.50
41/64
7/8
9
19.50
49/64
1
8
7/8
22.50
1-1/8
7
63/64
25.00
1-1/4
7
1-7/6
28.00
1-3/8
6
31.00
1-7/32
30.75
1-13/64
1-1/2
6
1-11/32
34.00
1-21/64
1-3/4
5
1-9/16
39.50
2
4-1/2
1-25/32
45.00
UNF - UNIFIED NATIONAL FINE
Size - Imperial
Threads Per Inch
TAPPING DRILL SIZE
Preferred
Alternative
mm
inch
mm
inch
#0
80
1.25
3/64
#1
72
1.55
53
#2
64
1.90
50
#3
56
2.15
45
#4
48
2.40
42
3/32
#5
44
2.70
37
2.65
#6
40
2.95
33
2.90
#8
36
3.60
9/64
3.50
29
#10
32
4.10
21
4.00
5/32
#12
28
4.70
14
4.60
1/4
28
5.50
7/32
5.40
3
5/16
24
6.90
17/64
6.80
1
3/8
24
8.50
Q
8.40
21/64
7/16
20
10.00
25/64
9.80
1/2
20
11.50
29/64
9/16
18
12.90
33/64
12.80
5/8
18
14.50
37/64
3/4
16
17.50
11/16
7/8
14
20.40
13/16
20.50
1
12
23.25
59/64
23.50
1
14*
23.50
15/16
1-1/8
12
26.50
1-3/64
1-1/4
12
29.50
1-11/64
1-3/8
12
33.00
1-19/64
1-1/2
12
36.00
1-27/64
*1-12 Thread is UNF standard, however 1-14 is popular demand and generally stocked in place of 1-12.
METRIC COARSE
Size - MM
Pitch
TAPPING DRILL SIZE
Preferred
Alternative
mm
inch
mm
inch
1.6
0.35
1.25
3/64
1.7
0.35
1.35
55
1.8
0.35
1.45
54
2
0.40
1.60
1/16
2.5
0.45
2.05
46
3
0.50
2.50
40
3.5
0.60
2.90
33
4
0.70
3.30
30
4.5
0.75
3.70
27
5
0.80
4.30
11/64
4.20
19
6
1.00
5.10
13/64
5.00
9
7
1.00
6.10
6.00
15/64
8
1.25
6.90
H
6.80
17/64
9
1.25
7.90
5/16
7.80
10
1.50
8.60
11/32
8.50
Q
11
1.50
9.50
3/8
12
1.75
13/32
10.20
Y
14
2.00
12.20
31/64
12.00
15/32
16
2.00
14.25
9/16
14.00
35/64
18
2.50
15.75
15.50
39/64
20
2.50
45/64
17.50
11/16
22
2.50
23/32
19.50
49/64
24
3.00
21.00
53/64
27
3.00
24.00
61/64
15/16
30
3.50
26.50
1-3/64
33
3.50
1-11/64
1-5/32
36
4.00
1-17/64
29.50
1-1/4
39
4.00
35.00
1-3/8
32.00
METRIC FINE
Size - MM
Pitch
TAPPING DRILL SIZE
Preferred
Alternative
mm
inch
mm
inch
4
0.50
3.50
29
9/64
5
0.50
4.50
16
6
0.75
5.25
5
7
0.75
6.25
D
6.2
1/4
8
1.00
7.00
J
7.1
9/32
10
1.25
8.75
11/32
S
10
1.00
9.00
T
23/64
12
1.50
10.50
27/64
Z
12
1.25
27/64
12
1.00
11.00
7/16
14
1.50
12.50
31/64
1/2
16
1.50
14.75
37/64
14.5
9/16
18
2.00
16.00
5/8
18
1.50
16.50
21/32
16.5
20
2.00
18.00
45/64
20
1.50
18.50
47/64
22
2.00
20.00
25/32
22
1.50
20.50
13/16
20.5
24
2.00
22.00
7/8
24
1.50
22.50
7/8
BSW - BRITISH STANDARD WHITWORTH
Size - Imperial
Threads Per Inch
TAPPING DRILL SIZE
Preferred
Alternative
mm
inch
mm
inch
1/16
60
1.20
3/64
1.05
3/32
48
1.90
49
1.75
1/8
40
2.55
2.50
3/32
5/32
32
3.20
1/8
2.95
3/16
24
3.70
3.60
9/64
7/32
24
4.50
4.30
11/64
1/4
20
5.10
5.00
3/16
5/16
18
6.50
6.40
1/4
3/8
16
7.90
5/16
7.80
19/64
7/16
14
9.50
9.20
23/64
1/2
12
10.50
13/32
9/16
12
12.00
15/32
5/8
11
13.50
17/32
33/64
3/4
10
16.50
41/64
16.00
5/8
7/8
9
3/4
19.00
47/64
1
8
22.00
55/64
27/32
1-1/8
7
31/32
24.50
61/64
1-1/4
7
28.00
1-3/32
27.50
1-5/64
1-1/2
6
33.50
1-5/16
33.00
1-19/64
1-3/4
5
39.00
1-17/32
38.50
1-33/64
2
1-1/2
44.50
1-49/64
44.00
1-3/4
BSF - BRITISH STANDARD FINE
Size - Imperial
Threads Per Inch
TAPPING DRILL SIZE
Preferred
Alternative
mm
inch
mm
inch
3/16
32
4.00
5/32
3.90
1/4
26
5.30
5.20
13/64
5/16
22
6.80
17/64
6.70
3/8
20
8.30
21/64
8.20
5/16
7/16
18
9.50
3/8
1/2
16
7/16
11.00
27/64
9/16
16
1/2
12.50
31/64
5/8
14
14.00
35/64
13.80
17/32
3/4
12
16.50
21/32
7/8
11
25/32
19.50
49/64
1
10
57/64
22.50
7/8
1-1/4
9
28.50
1-1/8
1-7/64
1-1/2
8
34.50
1-23/64
1-11/32
1-3/4
7
40.50
1-19/32
40.00
1-37/64
NPT - NATIONAL PIPE TAPER
Size - Imperial
Threads Per Inch
TAPPING DRILL SIZE
Preferred
Alternative
mm
inch
mm
inch
1/16
27
D
6.30
1/4
1/8
27
R
8.70
11/32
1/4
18
7/16
11.10
3/8
18
9/16
14.50
37/64
1/2
14
23/32
18.00
3/4
14
59/64
23.25
15/16
1
11-1/2
1-5/32
29.00
1-1/4
11-1/2
1-1/2
38.00
1-1/2
11-1/2
1-47/64
44.00
2
11-1/2
2-7/32
56.00
2-1/2
8
2-5/8
67.00
3
8
3-1/4
82.50
DRILL SIZE
DEC EQUIV.
MM
DRILL SIZE
DEC EQUIV.
MM
DRILL SIZE
DEC EQUIV.
MM
DRILL SIZE
DEC EQUIV.
MM
-
.0039
0.10
45
.0820
2.08
4
.2090
5.31
15/32
.4688
11.91
-
.0079
0.20
44
.0860
2.18
3
.2130
5.41
-
.4724
12.00
-
.0098
0.25
43
.0890
2.26
7/32
.2188
5.56
31/64
.4844
12.30
-
.0118
0.30
42
.0935
2.37
2
.2210
6.61
1/2
.5000
12.70
80
.0135
0.34
3/32
.0938
2.38
1
.2280
5.79
-
.5118
13.00
79
.0145
0.37
41
.0960
2.44
A
.2340
5.94
33/64
.5156
13.10
1/64
.0156
0.40
40
.0980
2.5
15/64
.2344
5.95
17/32
.5312
13.49
78
.0160
0.41
39
.0995
2.53
-
.2362
6.00
35/64
.5469
13.89
77
.0181
0.46
38
.1015
2.58
B
.2380
6.05
-
.5512
14.00
-
0.197
0.50
37
.1040
2.64
C
.2420
6.15
9/16
.5625
1429
76
.0200
0.51
36
.1065
2.71
D
.2460
6.25
37/64
.5781
14.68
75
.0210
0.53
7/64
.1094
2.78
1/4
.2500
6.35
-
.5906
15.00
74
.0225
0.57
35
.1100
2.79
E
.2500
6.35
19/32
.5938
15.08
-
.0236
0.60
34
.1110
2.79
F
.2570
6.53
39/64
.6094
15.48
73
.0240
0.61
33
.1130
2.87
G
.2610
6.63
5/8
.6250
15.88
72
.0250
0.64
32
.1160
2.95
17/64
.2656
6.75
-
.6299
16.00
71
.0260
0.66
-
.1181
3.00
H
.2660
6.76
41/64
.6406
16.27
-
.0276
0.70
31
.1200
3.05
I
.2720
6.91
21/32
.6562
16.67
70
.0280
0.71
1/8
.1250
3.18
-
.2756
7.00
-
.6693
17.00
69
.0292
0.74
30
.1285
3.26
J
.2770
7.04
43/64
.6719
17.07
-
.0295
0.75
29
.1360
3.45
K
.2810
7.14
11/16
.6875
17.46
68
.0310
0.79
28
.1405
3.57
9/32
.2812
7.14
45/64
.7031
17.88
1/32
.0313
0.79
9/64
.1406
3.57
L
.2900
7.37
-
.7087
18.00
-
.0315
0.80
27
.1440
3.66
M
.2950
7.49
23/32
.7188
18.26
67
.0320
0.81
26
.1470
3.73
19/64
.2969
7.54
47/64
.7344
18.65
66
.0330
0.84
25
.1495
3.80
N
.3020
7.67
-
.7344
18.65
65
.0350
0.89
24
.1520
3.86
5/16
.3125
7.94
3/4
.7500
19.05
-
.0354
0.90
23
.1540
3.91
-
.3150
8.00
49/64
.7656
19.45
64
.0360
0.91
5/32
.1562
3.97
O
.3160
8.03
25/32
.7812
19.84
63
.0370
0.94
22
.1570
3.99
P
.3230
8.20
-
.7874
20.00
62
.0380
0.97
-
.1575
4.00
21/64
.3281
8.33
51/64
.7969
20.24
61
.0394
0.99
21
.1590
4.04
Q
.2230
8.43
13/16
.8125
20.64
-
.0394
1.00
20
.1610
4.09
R
.3390
8.61
-
.8268
21.00
60
.0400
1.02
19
.1660
4.22
11/32
.3438
8.73
53/64
.8281
21.03
59
.0410
1.04
18
.1695
4.31
S
.3480
8.84
27/32
.8438
21.43
58
.0420
1.07
11/64
.1719
4.37
-
.3543
9.00
55/64
.8594
21.84
57
.0430
1.09
17
.1730
4.39
T
.3580
9.09
-
.8661
22.00
56
.0465
1.18
16
.1770
4.50
23/64
.3594
9.13
7/8
.8750
22.23
3/64
.0469
1.19
15
.1800
4.57
U
.3680
9.35
57/64
.8906
22.62
55
.0520
1.32
14
.1820
4.62
3/8
.3750
9.35
-
.9055
23.00
54
.0550
1.40
13
.1850
4.70
V
.3770
9.56
29/32
.9062
23.02
53
.0595
1.51
3/16
.1875
4.76
W
.3860
9.80
59/64
.9219
23.42
1/16
.0625
1.59
12
.1890
4.80
25/64
.3906
9.92
15/16
.9375
23.81
52
.0635
1.61
11
.1910
4.85
-
.3937
10.00
-
.9449
24.00
51
.0670
1.70
10
.1935
4.91
X
.3970
10.08
61/64
.9531
24.21
50
.0700
1.78
9
.1960
4.98
Y
.4040
10.26
31/32
.9688
24.61
49
.0730
1.85
-
.1968
5.00
13/32
.4062
10.32
-
.9842
25.00
48
.0760
1.93
8
.1990
5.05
Z
.4130
10.49
63/64
.9844
25.00
5/64
.0781
1.98
7
.2010
5.11
27/64
.4219
10.72
1
1.00
25.40
47
.0785
1.99
13/64
.2031
5.16
-
.4331
11.00
-
.0787
2.00
6
.2040
5.18
7/16
.4375
11.11
46
.0810
1.06
5
.2055
5.22
29/64
.4531
11.51
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