Drive Types
5 indexed entriesPart of Tools & Home Improvement.
Items
Hex / Allen
Hex (Allen) drives feature a 6-sided internal socket. Metric sizes range from 1.5mm to 19mm, while Imperial fractional sizes range from 1/16" to 3/4". Mixing metric and imperial drivers strips hex sockets.
Phillips vs Pozidriv
Phillips drives feature rounded corners and a 57° cross recess designed to cam out under high torque. Pozidriv has parallel ribs and a 45° drive angle with radial indicator marks. Using a Phillips bit in a Pozidriv screw strips the head.
Robertson (Square)
Robertson (square) drive uses a tapered square socket that grips the driver on all four sides, virtually eliminating cam-out. Patented by P.L. Robertson starting in 1907, it is color-coded by size -- orange #00 through black #3 -- and remains especially common in Canadian construction and woodworking.
Slotted (Flathead)
Slotted (flathead) is the oldest screw drive: a single straight slot cut across the head. ISO 2380-1 standardizes screwdriver blade widths from about 3/32 in (2.4mm) up to 1/2 in (13mm) for corresponding screw sizes. It has no built-in cam-out limit, so the blade can slip sideways under torque.
Torx
Torx (hexalobular internal) uses a 6-pointed star profile standardized in ISO 10664. Its 15-degree drive angle prevents driver cam-out, enabling higher torque transmission without damaging screw heads.