This is a T40 Torx (star) screwdriver bit, 30mm in working length with a 10mm shank, designed for driving Torx head fasteners where a compact, accurately indexed bit is required. Its primary use is for assembly and maintenance tasks that use Torx T40 fasteners, providing positive engagement with the star recess to reduce cam‑out and allow higher torque transmission than conventional Phillips or slotted bits.

The bit is manufactured from S2 tool steel that has been hardened and tempered to provide a durable cutting surface and resistance to deformation under load. The working tip conforms to the Torx T40 profile and is produced to industry Torx dimensional tolerances so it mates precisely with Torx fasteners. The shank measures 10mm, enabling use with 10mm bit holders, adapters and magnetic sockets; there is no threaded connection on the bit. The finish is a black phosphate coating which offers basic corrosion resistance and reduces glare in workshop environments. Typical hardness after heat treatment is in the HRC mid‑50s, giving a useful balance of toughness and wear resistance for general workshop and trade use.

Torx bits are used across a wide range of industries including automotive assembly and repair, agricultural machinery, aerospace sub‑assemblies, electronics assembly and general engineering maintenance. The T40 size is commonly found on larger fasteners in vehicle bodies, commercial plant, industrial enclosures and HVAC equipment. The bit is suitable for use in powered screwdrivers, right‑angle drivers, manual T‑handle drivers and impact drivers when used as specified for S2 bits and magnetic holders.

Key benefits include secure drive engagement with reduced cam‑out, a hardened S2 construction for dependable service life, and a 10mm shank for compatibility with common bit holders and sockets. The black phosphate finish helps resist surface corrosion and eases identification in mixed tool sets.

Duchy Fasteners holds a comprehensive range of Torx bits and accessories, with T‑sizes from small to large and a variety of lengths and shank options; this T40 x 30mm bit is available individually or in multi‑packs to suit trade, workshop and industrial requirements. If you need alternate lengths or bit packs, please check our stock list or contact us.