The DIN EN 22568 HSS-G fully ground circular dies for BSW threads are designed for producing external British Standard Whitworth threads according to BS 84 on rods, pins, studs, special screws, mechanical components, industrial spare parts and parts that need to be manufactured, reworked or repaired. BSW threads use a 55° Whitworth profile and are found on components built to British standards, older machinery, equipment, technical assemblies, vintage vehicles, inch-based fastening systems and applications requiring compatibility with non-metric Whitworth threads.

The fully ground HSS-G high-speed steel construction provides accurate cutting geometry, stable thread profile and consistent thread quality. The ground cutting edges allow smoother machining compared with non-ground tools, improving die feed, profile cleanliness and machining repeatability. The 55° profile and closed pre-slotted Form B geometry allow controlled external BSW threads to be produced according to the Whitworth thread form. The closed Form B design provides stable guidance when starting the die on the workpiece, while the pre-slotted construction helps distribute cutting forces and supports correct thread formation.

These dies are suitable for materials with tensile strength up to approximately 800 N/mm², including structural steels, unalloyed steels, mild steels, free-cutting steels, brass, bronze and metallic materials compatible with HSS-G cutting tools. They are particularly useful for mechanical workshops, maintenance technicians, toolrooms, production departments, automotive work, technical restoration, industrial repairs and machining of components with BSW standards. It is important to correctly distinguish BSW threads from UNC, UNF, BSP and metric threads, because profile, pitch, thread angle and mating compatibility are different.

The correct version must be selected according to Whitworth size, pitch in threads per inch, outside die diameter, die height and compatibility with the die holder being used. Correct size identification is essential, especially when restoring existing components, because apparently similar inch threads may not be interchangeable.

To obtain accurate threads, the external workpiece diameter must be prepared correctly, a suitable starting chamfer must be made, the die must be kept coaxial and perpendicular to the component axis, and appropriate cutting lubricant must be used. Incorrect workpiece diameter, misaligned starting, insufficient lubrication or unstable guidance can cause incomplete threads, torn profiles, increased cutting effort, premature die wear and poor engagement with nuts or female components. During machining, progressive cutting and periodic chip breaking are recommended, especially on larger sizes or tougher materials.