Screws have a gauge based on their diameter, just like wires
. A screw is named according to its diameter followed by the number of threads per inch. The ubiquitous 1/4-20 machine screw
, for example, has 20 threads per inch and a 1/4 inch diameter. The 1/4-20
, however, does not use the screw gauge scale. Screws that do include the 10-32, 8-32, etc.
, and drill
gauges, screw gauges go up with larger diameter, and it does not seem to be exactly standardized. The following are some screw gauge sizes, in inches