This product is a 1/8" BSPF (1" outside diameter) right‑hand split die manufactured in high‑speed steel for cutting or repairing 1/8" BSP parallel pipe threads. Its primary use is to form or restore BSP parallel (BSPP/BSPF) threads on round bar, fittings and short pipe stubs, using a hand die stock or compatible machine die holder for maintenance and fabrication work.

The die is produced from M2 high‑speed steel (HSS) with a bright, ground finish to the cutting faces. It cuts the BSP thread form (55° Whitworth profile) to the standard 1/8" size, 28 threads per inch (tpi), right‑hand direction. The split design permits slight adjustment of the effective diameter via the closing screw, allowing compensation for wear or fine tuning to fit mating components. Chamfered lead‑in faces ease start‑up and improve alignment when entering the workpiece. The thread form conforms to recognised BSP parallel thread geometry as defined by ISO 228‑1 (and associated British practice), so threads will be compatible with standard BSP parallel fittings and connections.

Typical applications include plumbing and hydraulic fixture repairs, instrumentation fittings, pneumatic and fluid power assemblies, marine and automotive service work, and general maintenance in workshops where parallel pipe threads are required. The die is suitable for cutting into mild steel, brass and aluminium bar; with appropriate cutting fluid and correct technique it can be used on stainless steels for occasional rework.

The key benefits of this HSS split die are its wear resistance and ability to retain hardness at elevated cutting temperatures (characteristics of M2 HSS), the adjustable split to prolong service life and achieve a better thread fit, and compatibility with standard BSP parallel fittings. As a manual or light machine tool it provides a cost‑effective method for on‑site thread repair and small batch production.

Duchy Fasteners stocks a broad range of HSS split dies, die stocks and taps, available in single units and multi‑packs. Sizes cover common BSP and metric thread forms; please contact us for availability of 1/8" BSPF and matching die holders (product code DIEPF0012).