The 13/16"-12 RH HSS split die is a round, adjustable cutting tool used to cut or restore external Unified Coarse (UNC) threads on cylindrical stock. Primarily intended for hand or machine use in a standard die stock, this split die produces 13/16" diameter threads with 12 threads per inch (13/16"-12 UNC), right-hand orientation, and is suitable for new thread cutting, thread repair and on-site maintenance.

This die is manufactured from M2 high speed steel (HSS) and hardened to a tool-grade hardness (typically around 60–62 HRC) to retain cutting edge and resist wear. The blank is ground to profile and supplied with a precision split and adjustment screw to allow fine control of thread fit. The thread form conforms to the Unified Coarse profile as defined by ANSI/ASME B1.1 and is produced to common tooling tolerances equivalent to a typical 2A external class fit for UNC threads. A black oxide finish is applied to reduce glare and provide light corrosion protection; as with all HSS tooling, the use of suitable cutting oil is recommended to prolong tool life and improve chip evacuation.

Typical applications include producing external fastener threads on studs and shafts, repairing damaged or corroded threads on agricultural and automotive components, and maintenance tasks in engineering workshops. Industries that commonly use this die include automotive and motorsport repair, agricultural machinery maintenance, heavy plant and construction equipment servicing, and general engineering and fabrication where imperial fasteners are employed.

Key benefits of this 13/16"-12 HSS split die are the wear resistance and heat tolerance of M2 HSS, the adjustability provided by the split design which allows correction for light oversize or undersize conditions, and compatibility with standard die stocks and holding tools. The die produces Unified Coarse threads compatible with UNC fasteners and nuts, making it suitable for repair and assembly work where interchangeability is required.

Duchy Fasteners stocks a comprehensive range of split dies and die sets in both imperial and metric sizes. This 13/16"-12 UNC split die is available as a single item and within assorted packs; please contact us for specific sizes, pack quantities and availability.