This is a 41 mm bi‑hex (12‑point) socket designed for use with 3/4 inch square‑drive ratchets, breaker bars and torque wrenches. Its primary use is to apply and remove large metric hex fasteners where higher torque and access in confined spaces are required, for example wheel nuts on heavy vehicles, large hydraulic fittings and structural bolting on plant and machinery.

The socket is manufactured from heat‑treated chrome vanadium (Cr‑V) steel to provide the toughness and fatigue resistance required for heavy duty workshop use. The external surface is chrome‑plated to resist corrosion and to make cleaning simple after exposure to grease and workshop fluids. The 12‑point bi‑hex profile permits engagement on either the flats or the points of a fastener, allowing easier alignment with fasteners in tight clearances and facilitating use with indexed or angled approach. The socket accepts a 3/4 in square drive and is compatible with standard 3/4 in drive tools and extensions.

Dimensions and tolerances are produced to recognised hand‑tool standards (DIN 3122 and ISO 1174) and are compatible with typical British Standard hand‑tool tolerances. The larger 3/4 in drive transmits high torque safely—making this socket suitable for heavy commercial, agricultural, plant maintenance, rail, marine and oil & gas industries where robust fastener removal and tightening is needed.

Typical applications include heavy truck and trailer maintenance, installation and servicing of construction plant (excavators, loaders), tightening hydraulic and pipework flange bolts, and general maintenance where 41 mm metric fasteners are used. Key benefits include the corrosion resistance of the chrome finish, the strength and impact resistance of heat‑treated Cr‑V steel, and the versatility of the 12‑point profile which reduces rounding on damaged fasteners and allows use in tighter access situations than a 6‑point socket.

Duchy Fasteners stocks this 41 mm bi‑hex 3/4 in drive socket across a range of lengths and in single‑unit packs or mixed 3/4 in drive sets. Contact us for availability of alternative sizes and bulk pack options.