This is a 4 mm right‑hand (RH) split die manufactured from high speed steel, designed for cutting or restoring external metric threads — typically M4 × 0.7. The split design gives a slight radial adjustment so you can tighten or relax the die in a standard die stock to obtain a close or loose thread fit and to compensate for wear or material differences. Its primary use is on bar, rod or stud material where a clean, accurate external thread is required during fabrication or repair.

The die is produced from M2 grade high speed steel (HSS), precision ground and heat treated to provide the hardness and toughness needed for repeated cutting operations in mild steel, brass, aluminium and certain plastics when used with appropriate lubrication. The thread form conforms to the ISO metric 60° profile (compatible with DIN 13 / ISO 68‑1 nominal forms) and is supplied as a right‑hand thread. The unit is unmounted and intended for use with a standard T‑type or adjustable die stock; the split cut allows controlled adjustment of the effective thread size.

Typical applications include machine shop maintenance, prototyping, general engineering, instrument making and small‑batch production where restoring or forming external threads is required. It is commonly used in automotive repair, electrical enclosures, bracket manufacture and any situation where M4 fastenings are needed but tapped components are not available.

Key benefits of an M2 HSS split die are dimensional stability and wear resistance under repeated cutting, with the split feature giving fine control of thread fit. While HSS is not stainless, it offers better corrosion resistance than untreated carbon tool steels; routine oiling after use will prolong life. The die’s compatibility with standard die holders and the ISO metric thread form makes it straightforward to integrate into existing tooling and assembly processes.

Duchy Fasteners carries a wide range of split dies and matching die stocks in common metric sizes. Items are available individually or in multi‑packs to suit workshop or production requirements; please contact us for specific size and pack availability.