Hertel K010374AS Thread Forming Tap 1/4-28 Unf Bottoming Hss

Product Description

The HERTEL K010374AS is a thread forming tap designed for blind hole threading in 1/4-28 UNF applications. Unlike cutting taps, thread forming taps displace material rather than cut it, producing stronger threads with no chips to clear from the hole. This tap is manufactured from high-speed steel with a bright, uncoated finish and carries a 2B class of fit with an H4 thread limit. It features a bottoming chamfer of 1 to 2 threads, making it suited for threading close to the bottom of a blind hole. Overall length is 2.5 inches with a thread length of 1 inch. Machinists, tool and die makers, and maintenance technicians install this type of tap in production and repair environments.

This tap is intended for blind hole threading in ductile and malleable materials where thread forming is appropriate, such as aluminum, brass, and low-carbon steel. The bottoming chamfer design allows threading to within a few pitches of the bottom of a blind hole, which is critical in tight-tolerance assemblies. The right-hand thread direction follows standard UNF conventions. It is used in machine shops, manufacturing cells, and MRO applications where a 1/4-28 UNF internal thread is required and chip-free thread production is preferred over cutting.

Key Features

• Bottoming chamfer (1-2P) for threading close to the bottom of blind holes
• Thread forming design displaces material, producing stronger threads with no chips
• High-speed steel construction for durability across a range of ductile materials
• Bright, uncoated finish suitable for use with cutting fluids or tapping compounds
• H4 thread limit for consistent 2B class of fit on 1/4-28 UNF threads
• Right-hand thread direction per standard UNF practice

Compatibility

Designed as a direct-use thread forming tap for 1/4-28 UNF blind hole applications in ductile and malleable workpiece materials. Verify workpiece material suitability before use, as thread forming taps are not appropriate for brittle materials such as cast iron or hardened steel.

Installation Notes

Thread forming taps require a properly sized forming tap drill hole, which is larger than the equivalent cutting tap drill size - consult a thread forming tap drill chart for the correct pilot hole diameter before use. Apply an appropriate tapping fluid or compound for the workpiece material. Secure the workpiece and ensure the tap is driven perpendicular to the surface to avoid tap breakage or thread distortion. This tap is intended for use by trained machinists or maintenance personnel familiar with threading operations and proper tap speed and feed selection.