RECOMMENDED DRILL SIZES
FOR
SELF-TAPPING SCREWS (SHEET METAL)
|
Self-Tapping
Screw Size
|
Major
Thread Diameter
|
Minor
Thread Diameter
|
For
Heavy Metals
|
For
Light Metals
|
||||||||
|
No. |
Threads per Inch |
O.D. |
Max. |
Mean
|
Min.
|
Max.
|
Mean
|
Min.
|
Drill
Size
|
Drill
Size
|
||
|
2
|
32
|
.086
|
.088
|
.0850
|
.082
|
.064
|
.0620
|
.060
|
49
|
.0730
|
49
|
.0730
|
|
4
|
24
|
.112
|
.114
|
.1110
|
.108
|
.086
|
.0840
|
.082
|
41
|
.0960
|
41
|
.0960
|
|
5
|
20
|
.125
|
.130
|
.1265
|
.123
|
.094
|
.0920
|
.090
|
36
|
.1065
|
36
|
.1065
|
|
6
|
20
|
.138
|
.139
|
.1355
|
.132
|
.104
|
.1015
|
.099
|
32
|
.1160
|
32
|
.1160
|
|
7
|
19
|
.151
|
.154
|
.1505
|
.147
|
.115
|
.1120
|
.109
|
30
|
.1285
|
30
|
.1285
|
|
8
|
18
|
.164
|
.166
|
.1625
|
.159
|
.122
|
.1190
|
.116
|
28
|
.1405
|
29
|
.1360
|
|
10
|
16
|
.190
|
.189
|
.1855
|
.182
|
.141
|
.1380
|
.135
|
20
|
.1610
|
21
|
.1590
|
|
12
|
14
|
.216
|
.215
|
.2115
|
.208
|
.164
|
.1605
|
.157
|
13
|
.1850
|
14
|
.1820
|
|
1/4
|
14
|
.250
|
.246
|
.2415
|
.237
|
.192
|
.1885
|
.185
|
3
|
.2130
|
4
|
.2090
|
|
5/16
|
12
|
.313
|
.315
|
.3105
|
.306
|
.244
|
.2400
|
.236
|
I
|
.2720
|
H
|
.2660
|
|
3/8
|
12
|
.375
|
.380
|
.3755
|
.371
|
.309
|
.3040
|
.299
|
R
|
.3390
|
Q
|
.3320
|
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