A 3mm hexagon key is an L‑shaped hand tool used to drive fasteners with a 3.0 mm hexagonal (6‑point) socket. It provides the correct across‑flats contact to tighten or loosen hex socket screws, set screws and bolts where a compact, low‑profile drive is required. The primary use case is assembly and maintenance work where metric hex socket fasteners are specified.

This version from the Draper Tools Group D line is manufactured from hardened chrome‑vanadium (CrV) / S2 tool steel and has been heat treated to give a durable working hardness and good resistance to wear. The surface is finished with a black oxide coating to reduce corrosion and minimise light reflection in workshop environments. The tool conforms to standard metric L‑key dimensions used in production and maintenance (equivalent to ISO/DIN metric hex key profiles), the drive type is a straight hexagon (no ball end) and the head is the classic short/long arm L shape. Thread type is not applicable to the tool itself; it is designed for hex socket fasteners complying with metric socket standards.

Typical applications include general engineering and mechanical assembly, plant maintenance, furniture fitting, bicycle and motorcycle servicing, electrical panel work and precision equipment assembly. It is useful wherever confined access requires a slim hex key and where controlled torque application is needed to avoid rounding socket heads. Industries that commonly use 3mm hex keys are light manufacturing, maintenance & facilities, automotive repair, and joinery/furniture manufacture.

Key benefits include improved corrosion resistance from the black oxide finish, enhanced toughness and edge retention from heat treatment of CrV/S2 steel, and dimensional compatibility with standard metric hex socket fasteners to reduce the risk of strip‑out. The L‑shape provides two working distances: the short arm for higher torque and the long arm for reach and leverage.

Duchy Fasteners stocks the DR33498 3mm hexagon key as single items and within metric L‑key sets. We hold both short and long arm lengths and a range of pack sizes to suit tradesmen, workshops and production requirements.