This is a 5/16in AF bi‑hex (12‑point) socket with a 1/2in square drive, designed to fit 5/16 inch across‑flats imperial hex fasteners. Its primary use is with 1/2in drive ratchets, torque wrenches and breaker bars for loosening and tightening bolts and nuts where a compact engagement angle and robust drive connection are required.

The socket is manufactured from chrome‑vanadium steel (Cr‑V) and is heat treated, hardened and tempered to give good torsional strength and fatigue resistance. The exterior is chrome plated to resist corrosion and to provide a smooth surface for tool handling. The product uses a 12‑point bi‑hex internal profile manufactured to the common ISO/DIN 12‑point geometries for sockets, and it accepts a standard 1/2in square drive on the outer face. There is no threaded connection on the socket; it is a push‑fit onto standard 1/2in drive tools.

Typical applications include automotive and heavy vehicle maintenance, industrial plant repair, agricultural machinery servicing and general mechanical engineering. The 12‑point profile is particularly useful where access is restricted: it allows engagement every 30 degrees, reducing the swing arc needed to reposition the drive. Workshops, fleet maintenance departments and onsite service engineers frequently specify this style of socket for situations where speed of operation and repeatable engagement are important.

Key benefits include good corrosion resistance from the chrome finish and high torque capability from the heat‑treated Cr‑V construction. The 12‑point (bi‑hex) shape increases the number of engagement positions, improving usability in confined spaces; it will also engage 6‑point fasteners, although dedicated 6‑point sockets remain preferable for the very highest torque applications to maximise bearing surface. The 1/2in drive is widely compatible with a large range of ratchets, extensions and impact‑resistant drive accessories.

Duchy Fasteners stocks this Draper 5/16in AF bi‑hex 1/2in drive socket individually and as part of socket sets. We carry a wide range of imperial and metric sockets in single pieces and assorted packs — please check our website or contact us for current sizes and pack quantities.