A hexalobular drive recess, or external head, with six rounded lobes, sized by a T number such as T25 or T30. The nearly parallel drive walls push tangentially instead of outward, so the bit does not ride up and out and the recess survives repeated assembly with power tools. Tamper-resistant versions add a center pin, and Torx Plus and external E-Torx are related shapes that are not interchangeable with the standard bit.
Seat bolts are T50 Torx and they're in there tight, so put the bit on a breaker bar and keep it square.
Also heard as
- star drive
- hexalobular
- six-lobe
Related terms
Phillips
A cross-shaped recess drive with tapered walls, the default drive on sheet metal, wood and small machine screws.
Cam-out
The driver bit climbing out of a screw recess under torque, chewing up the recess and wearing the bit.
Robertson
A square-socket screw drive, standard in Canadian construction, with color-coded bit and handle sizes.
Allen key
Shop name for an L-shaped hex key used to drive socket head cap screws and set screws.