Internal Hex, Internal Torx, External Hex, TX, Hex
Imperial, Metric, AF, Torx, SAE
4 mm, 7/32 ", 9/32 ", 5/16 ", 9/16 "
1/2, 1-1/2, 1, 1/4, 2-1/2
38.1, 9.53, 6.35, 19.05, 25.4
Special Steel, Molybdenum Steel, Alloy Steel, Steel, Chrome Molybdenum Alloy Steel
Phosphatized, Phosphated, Oxidised, Black Phosphate, Black Oxide