Tapping Screw Gauge to Metric Size
The nominal diameter of a self tapping screw can be identified in metric mm or imperial gauge size.
For example a No.6 gauge self tapping screw is also a 3.5mm self tapping screw. The nominal diameter can be measured across the threaded portion of the tapping screw.
The accompanying table shows imperial gauge diameters and their metric equivalent.
Gauge | No.2 | No.4 | No.6 | No.7 | No.8 | No.10 | No.12 | No.14 | No.16 |
---|---|---|---|---|---|---|---|---|---|
mm | 2.2 | 2.9 | 3.5 | 3.9 | 4.2 | 4.8 | 5.5 | 6.3 | 8.0 |

For more detailed information please view the following pages:
Square Drive Pan Tapping Screw Standard
Square Drive Csk Tapping Screw Standard
View all available Self Tapping Screws