Nominal Size Major Dia. Minor Dia. Point Dia Point Taper Length Minimum Practical screw Length 6 20 .139 .132 .104 .099 .095 .089 .100 .075 1/4 9/32 7 19 .154 .147 .115 .109 .105 .099 .105 .079 1/4 5/16 8 18 .166 .159 .122 .116 .112 .106 .111 .083 9/32 11/32 10 16 .189 .182 .141 .135 .130 .123 .125 .094 5/16 3/8 12 14 .215 .208 .164 .157 .152 .145 .143 .107 11/32 7/16 14 14 .246 .237 .192 .185 .179 .171 .143 .107 3/8 1/2
Threads For Self-Tapping Screws Type B ANSI
B18.6.4
Threads per Inch
Max
Min
Max
Min
Max
Min
Max
Min
90° Heads
Csk
Heads
Suggest Test Plate Thickness & Hole Sizes for Types AB, B, 25 | |||||
Nominal Size |
Thickness |
Hole Size | |||
Gage |
Max |
Min |
Drill Size |
Hole Dia. | |
2-32 |
18 |
.0500 |
.0460 |
48 |
.0760 |
3-28 |
18 |
.0500 |
.0460 |
46 |
.0810 |
4-24 |
18 |
.0500 |
.0460 |
44 |
.0860 |
5-20 |
18 |
.0500 |
.0460 |
36 |
.1065 |
6-20 |
14 |
.0770 |
.0730 |
32 |
.1160 |
7-19 |
14 |
.0770 |
.0730 |
30 |
.1285 |
8-18 |
14 |
.1270 |
.1230 |
29 |
.1360 |
10-16 |
1/8 |
.1270 |
.1230 |
21 |
.1590 |
12-14 |
1/8 |
.1270 |
.1230 |
3/16 |
.1875 |
¼-14 |
3/16 |
.1905 |
.1845 |
5.5mm |
.2165 |
5/16-12 |
3/16 |
.1905 |
.1845 |
I |
.2720 |
3/8-12 |
3/16 |
.1905 |
.1845 |
21/64 |
.3281 |