This is an 18 mm × 1.0 HSS split die, a circular external thread-cutting tool intended for producing or repairing M18 × 1.0 metric fine threads on shafts and studs. The split die is used in a hand-operated die stock or compatible machine die holder to cut new threads, chase damaged threads, or restore thread form to worn components where a fine-pitch M18 is required.

The die is manufactured from M2 high speed steel (HSS) and is precision ground to size. It is heat-treated and tempered to provide a durable cutting edge and long tool life. The product conforms to ISO metric thread form standards (ISO 68‑1 for thread profile and ISO 965‑1 for tolerances) and is suitable for threads made to DIN 13 and BS 3643 specifications. The 18 mm diameter with 1.0 mm pitch is a fine-pitch metric external thread (M18 × 1.0). The split configuration allows controlled adjustment of the thread depth when clamped in a standard die stock, enabling light trimming or tighter fitment. The die has a bright ground finish; it is a tool steel product and should be stored oiled to minimise surface corrosion.

Because it is made from M2 HSS, this split die is suitable for cutting threads in mild steel, medium alloy steels, stainless steels (work-hardened grades may need slow feeds and cutting fluid), aluminium, brass and many engineering plastics. It is commonly used in engineering and maintenance workshops, automotive and hydraulic fitting repairs, precision instrument manufacture, and general mechanical fabrication where fine-pitch M18 fastenings are required.

Key benefits include the wear resistance and edge retention of M2 HSS, the fine-pitch accuracy compatible with ISO/DIN/BS thread standards, and the adjustability of the split design which aids reconditioning and on-site repair work. The die will not provide corrosion protection itself, so use appropriate lubricants during cutting and protect the tool in storage.

Duchy Fasteners stocks split dies across the metric range; this item is available individually and in multi-packs, and we also supply compatible die stocks and cutting fluids. Contact us for availability of other sizes, alternative pitches or bulk requirements.