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Self Tapping Screw
These screws are generally designed for fastening sheet metal (or thin metal). They cut threads into the material when tightened to secure into place. Most can start their own hole (self-piercing) but some may require a pilot hole, especially with larger sizes. Can be used with materials other than sheet metal, such as wood or plastic.
Other Names: Sheet Metal Screws, SMS, Zip Screw
Types: There are three different types A, B, and AB. Type AB is the most common type, featuring finer threads and a sharp point. Type A has wider spaced threads and sharp point. Type B has a blunt point but finer threads.
Dimensions - Type AB
ASME B18.6.4
| Dia. | Thread | Hex | Rec. Sheet Thickness |
|---|---|---|---|
| 2 | 32 | 0.0460 - 0.0500 | |
| 3 | 28 | 0.0460 - 0.0500 | |
| 4 | 24 | 0.0460 - 0.0500 | |
| 5 | 20 | 0.0460 - 0.0500 | |
| 6 | 20 | 1/4 | 0.0730 - 0.0770 |
| 7 | 19 | 1/4 | 0.0730 - 0.0770 |
| 8 | 18 | 1/4 | 0.1230 - 0.1270 |
| 10 | 16 | 5/16 | 0.1230 - 0.1270 |
| 12 | 14 | 5/16 | 0.1230 - 0.1270 |
| 1/4 | 14 | 3/8 | 0.1845 - 0.1905 |
| 5/16 | 12 | 1/2 | 0.1845 - 0.1905 |