How it connects
Slip-on fit: the female hex is pushed axially over the male hex and drives it by flank contact; held only by clearance friction or a magnet, no seal and no locking.
Male and female halves
This is the female (socket) half; the male half is the external hex of a nut or bolt head. Sized by width across flats of the hex it fits.
Usually connects to
Common sizes
- Sized by across-flats: inch about 3/16" to 3/4" (5/16" common for no-hub clamps and hex-washer-head screws), metric about 3 mm to 24 mm.
Where it is used
hand toolspower-tool nut settersplumbing (no-hub coupling torque wrenches)fastening / assembly
Variations
- 6-point vs 12-point
- magnetic vs non-magnetic tip
- hollow shaft nut driver
- 1/4" hex-shank nut setter
- inch (SAE) vs metric across-flats
How to recognise it
A cylindrical tool end with a six-flat hexagonal hole, often with the across-flats size stamped on the side (e.g. 5/16", 14mm), on a handle, T-handle torque wrench or 1/4" hex shank.
Often confused with
| Confused with | How to tell them apart |
|---|---|
| Square drive socket (1/4", 3/8", 1/2") | Square drive is the 4-sided hole at the back of a socket that takes a ratchet; the hex nut socket is the 6-sided front opening. |
| 1/4" hex shank (male hex bit drive) | The hex shank is a male hex on the driver end that fits a drill chuck or bit holder; the nut socket is a female hex at the working end. |
| Hex key / Allen socket (internal hex drive) | Allen drive uses a male hex key into a female recess in the screw head; here the tool is female and the fastener is male. |
| 12-point socket | 12-point has twelve star-like points inside; 6-point has six flat flanks. |
Also called
6-point socketnut driver tipnut setterfemale hex drive
Good to know
This is a tool-to-fastener drive interface, not a pipe/electrical connection. ISO 2725 / ASME B107.x define socket wrench dimensions, but not verified here so left out of standards. Size is the fastener's across-flats, not a thread size.
Related connections
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