HSS Left‑Hand Threading Dies are specialised tools designed for cutting, repairing, and restoring external threads that rotate in the opposite direction to standard right‑hand threads. Manufactured from high‑speed steel, these dies deliver excellent hardness, wear resistance, and precise cutting performance, making them ideal for applications where reverse‑rotation components are required.
Left‑hand threads are commonly used for rotating machinery, shafts, automotive components, mechanical locking systems, and assemblies where vibration or rotational torque would loosen a standard fastener. These dies are available in both metric (M‑series) and imperial (UNF/UNC) thread forms to cover a wide variety of engineering, workshop, and maintenance needs.
Their precision‑ground cutting edges ensure smooth chip flow, accurate thread geometry, and consistent results across common workshop metals including mild steel, stainless steel, brass, and aluminium. With a range of OD sizes for compatibility with standard die stocks, HSS L/H Dies are an essential solution for technicians, engineers, and fabricators working with reverse‑thread components.