|
| | |
|

|
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 |
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 |
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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