TAP DRILL SIZES
FOR THREAD FORMING TAPS
TAP SIZE |
TAP DRILL SIZE |
DECIMAL EQUIV. |
PERCENT OF THREAD |
0-80 |
1.35mm
#54 |
.0531
.0550 |
81
59 |
1-64 |
1.65mm
#51 |
.0650
.0670 |
75
56 |
1-72 |
1.65mm
#51 |
.0650
.067 |
85
64 |
2-56 |
1.95mm
#47
2.0mm |
.0768
.0785
.0787 |
76
62
60 |
2-64 |
#47
2.0mm
2.05mm |
.0785
.0787
.080 |
71
69
49 |
3-48 |
2.25mm
#43
2.3mm |
.0886
.0890
.0906 |
73
71
59 |
3-56 |
#43
2.3mm
2.35mm |
.0890
.0906
.0925 |
82
69
54 |
4-40 |
#39
#38
2.6mm |
.0995
.1015
.1024 |
74
62
57 |
4-48 |
#38
2.6mm
#37 |
.1015
.1024
.1040 |
74
68
57 |
5-40 |
#34
2.9mm
#32 |
.1110
.1142
.1160 |
82
64
53 |
5-44 |
#33
2.9mm
#32 |
.1130
.1142
.1160 |
78
70
58 |
6-32 |
3.1mm
1/8
3.2mm |
.1220
.1250
.126 |
75
61
56 |
6-40 |
1/8
3.2mm
#30 |
.125
.126
.1285 |
76
71
56 |
8-32 |
3.75mm
#25
#24 |
.1476
.1485
.1520 |
77
68
56 |
8-36 |
#25
#24
#23 |
.1495
.1520
.1540 |
77
64
53 |
10-24 |
#18
11/64
#17 |
.1695
.1719
.1730 |
72
64
60 |
10-32 |
#17
#16
#15 |
.1730
.177
.1800 |
80
61
47 |
12-24 |
#10
5.0mm
#7 |
.1935
.1968
.2011 |
79
68
53 |
12-28 |
5.0mm
5.1mm
13/64 |
.1968
.2008
.2031 |
79
63
53 |
1/4-20 |
5.7mm
#1
5.9mm |
.2244
.2280
.2323 |
75
65
52 |
1/4-28 |
5.9mm
15/64
6.0mm |
.2323
.2344
.2362 |
73
64
57 |
5/16-18 |
7.25mm
I
7.4mm |
.2854
.2900
.2913 |
72
60
56 |
5/16-24 |
7.4mm
M
19/64 |
.2913
.2950
.2969 |
75
62
55 |
3/8-16 |
8.75mm
S
8.9mm |
.3445
.3480
.3504 |
72
64
58 |
3/8-24 |
9.0mm
23/64 |
.3543
.3594 |
73
55 |
7/16-14 |
Y
13/32
Z |
.4040
.4062
.4130 |
69
64
50 |
7/16-20 |
Z |
.4130 |
72 |
1/2-13 |
15/32
12mm |
.4688
.4724 |
60
53 |
1/2-20 |
12mm |
.4724 |
81 |
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