Wiseman HSS UNEF Split Dies – Unified Extra Fine Right Hand Thread

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

These precision-engineered round split dies feature an adjustable split design, allowing minor adjustments to the thread fit when used with a suitable die stock. This makes them particularly useful for precision engineering, thread cutting, maintenance and specialist workshop applications.

UNEF threads feature a 60° thread profile and a finer pitch than UNC (Unified National Coarse) and UNF (Unified National Fine) threads of the same nominal diameter. Unified National Extra Fine threads are commonly specified in precision engineering, automotive, aerospace and specialist machinery applications where fine thread adjustment or limited thread engagement depth is required.

Manufactured with a right-hand thread profile, these split dies are suitable for producing and restoring UNEF threads on bolts, studs, rods and other externally threaded components.

Key Features

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

• UNEF Thread Form – Designed for Unified National Extra 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.

• 60° Thread Profile – Unified thread form featuring an extra-fine thread pitch.

• Precision Thread Cutting – Suitable for applications requiring fine-pitch external threads.

• Professional Quality – Manufactured by Wiseman Threading Tools for engineering and workshop applications.

Applications

Suitable for:

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

• Repairing damaged or worn UNEF threads.

• Cleaning and restoring existing external threads.

• Precision engineering and workshop machining.

• Automotive and specialist machinery repairs.

• Aerospace maintenance where approved tooling and procedures permit.

• Fabrication and maintenance of fine-pitch threaded components.

• Manufacturing replacement bolts and studs.

• Applications requiring Unified National Extra Fine threads.

Recommended Use

Select the correct UNEF split die size and pitch to match the required external thread.

Secure the die in a suitable 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 help 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 thread gauge or mating component.

Important

• Suitable for UNEF (Unified National Extra Fine) right-hand external threads only.

• Not compatible with 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.

• Ensure the correct thread diameter and threads per inch (TPI) are selected before use.