BSPF BRITISH STANDARD PIPE FASTENING DIE NUTS

BSPF (British Standard Pipe Fastening) die nuts are hex-shaped threading tools used to repair, clean, and chase damaged male threads on pipes and fittings. Unlike standard round cutting dies, die nuts are turned with a conventional wrench or socket rather than a specialized die stock.

• Purpose: They are strictly for re-threading or cleaning existing bruised, rusty, or cross-threaded pipes. They are not designed to cut brand-new threads from blank stock.
• Thread Type: BSPF represents a parallel (straight) thread with a 55° thread angle, commonly used for mechanical fastening in plumbing and pipe joints.
• Shape: Six-sided (hexagonal) design allows easy operation in tight spaces using standard standard spanners, adjustable wrenches, or sockets. 

1. Clean the workpiece: Remove heavy rust or debris from the damaged thread with a wire brush.
2. Lubricate generously: Apply cutting oil or a heavy lubricant to reduce friction and prevent thread galling.
3. Align carefully: Place the die nut by hand onto the good portion of the thread to ensure it is perfectly straight and not cross-threaded.
4. Turn with a wrench: Fit a matching socket or spanner over the hex nut and rotate it clockwise. Back off a quarter-turn for every full turn forward to clear out metal chips.

BREAKDOWN OF 1/8 X 28TPI DIE NUT

• 1/8": This is the nominal pipe size, not the physical outer diameter of the thread or tool. A 1/8" BSP pipe has an actual external thread major diameter of approximately 9.73 mm (0.383 inches)
• BSPF: Stands for British Standard Pipe Fastening (also designated globally as G-threads). This denotes a parallel, non-tapering thread with a 55° Whitworth thread angle. It relies on a washer or O-ring rather than the thread itself to form a liquid-tight seal.
• Carbon (Carbon Steel): The material composition. Carbon steel dies feature a bright finish and are optimal for maintenance, DIY, and general-purpose work on softer materials like brass, copper, aluminum, and plastics. They are intended for standard upkeep rather than manufacturing high-precision, safety-critical threads. 
• Die Nut: A six-sided (hexagonal) thread-restoration tool. Unlike circular button dies that require a specialized round die-stock holder, a die nut has an Across Flats (AF) width of 23.5 mm, meaning it can be driven by a standard spanner, adjustable wrench, or deep socket.