Wiseman HSS BSF Split Dies – British Standard Fine Right Hand Thread

Wiseman HSS BSF Split Dies are manufactured from High Speed Steel (HSS) and designed for cutting new external BSF (British Standard Fine) threads, as well as repairing, cleaning and restoring damaged or worn existing threads.

These round split dies feature an adjustable design, allowing minor adjustments to the thread fit when used with a suitable die stock. They are ideal for general engineering, thread cutting, maintenance and restoration applications.

BSF threads feature a 55° Whitworth thread profile with rounded crests and roots, but have a finer thread pitch than BSW (British Standard Whitworth) threads of the same nominal diameter. British Standard Fine threads are commonly found on older British machinery, classic vehicles, motorcycles, agricultural equipment and traditional engineering components.

Designed for right-hand thread cutting, these split dies are suitable for producing and restoring BSF threads on bolts, studs, rods and other externally threaded components.

Key Features

• High Speed Steel (HSS) – Durable construction for reliable thread cutting and maintenance.

• BSF Thread Form – Designed for British Standard Fine external threads.

• Right Hand Thread – Standard clockwise tightening thread direction.

• Adjustable Split Design – Allows minor adjustment of the thread fit when used with a suitable die stock.

• Round Die Construction – Designed for use with compatible die stocks and die holders.

• Thread Cutting & Restoration – Suitable for cutting new external threads and repairing existing threads.

• 55° Whitworth Thread Profile – Features rounded crests and roots with a finer pitch than BSW.

• Restoration Applications – Particularly useful for classic vehicles and older British machinery.

• Engineering & Workshop Use – Suitable for general machining, fabrication and maintenance.

Applications

Suitable for:

• Cutting new BSF external threads on rods, bolts and studs.

• Repairing damaged or worn BSF threads.

• Cleaning and restoring existing external threads.

• Classic car and vintage motorcycle restoration.

• Maintenance of older British machinery and equipment.

• Agricultural machinery repairs.

• General engineering and workshop machining.

• Manufacturing replacement bolts and studs.

• Applications requiring British Standard Fine threads.

Recommended Use

Select the correct BSF split die size and threads per inch (TPI) to match the required external thread.

Secure the die in a compatible die stock or holder, ensuring the adjustment screws are correctly positioned. Prepare the workpiece to the appropriate diameter and apply a suitable chamfer to help the die start squarely.

Apply an appropriate cutting lubricant and rotate the die clockwise to cut the thread. Periodically reverse the die slightly to break and clear chips where appropriate for the material and cutting conditions.

The adjustable split design allows minor adjustments to the thread fit. For accurate results, check the finished thread using a suitable BSF thread gauge or correctly specified mating component.

Important

• Suitable for BSF (British Standard Fine) right-hand external threads only.

• Not interchangeable with BSW, UNC, UNF, metric or other thread forms.

• Adjustable round split die for cutting and restoring external threads.

• Requires a compatible die stock or die holder.

• Select the correct nominal diameter and TPI before use.