Guhring 9039020063500 Spiral Point Tap 1/4-28 Unf

Product Description

The GUHRING 9039020063500 is a spiral point tap designed for right-hand, through-hole threading in steel. It cuts a 1/4-28 UNF thread to a 2B class of fit using three flutes and a plug chamfer that guides the tap smoothly into the workpiece. The tap is manufactured from HSS-E cobalt high-speed steel, which provides elevated heat and wear resistance compared to standard HSS. Overall length is 2.5 inches, thread length is 0.625 inches, and shank diameter is 0.255 inches. It carries a bright, uncoated finish and belongs to GUHRING Series 3902.

This tap is suited for through-hole threading operations in steel workpieces where chips can be pushed forward out of the hole rather than backed out. The plug chamfer — typically 3 to 5 threads — makes it appropriate for starting in a drilled through-hole with adequate material depth. It is commonly used in machining, fabrication, and maintenance environments where 1/4-28 UNF fastener threads are required. The H3/H4 thread limit provides a controlled oversize tolerance suitable for standard 2B fit fastener assemblies.

Key Features

• HSS-E cobalt material offers improved heat resistance and tool life in steel applications
• Spiral point geometry pushes chips forward, making it effective in through-hole applications
• Plug chamfer provides stable thread lead-in for consistent thread starts
• H3/H4 thread limit delivers controlled tolerance for standard 2B class of fit
• Bright, uncoated finish — no coating buildup to affect thread tolerance in tight applications
• Right-hand thread direction compatible with standard right-hand fastener assemblies

Compatibility

Designed for through-hole threading of 1/4-28 UNF threads in steel. The 2B class of fit and H3/H4 thread limit are compatible with standard 1/4-28 UNF fastener assemblies requiring a free or close fit per ASME B1.1 standards.

Installation Notes

This tap is intended for use by machinists and fabricators operating drill presses, CNC machining centers, or hand tapping equipment. Secure the workpiece fully before tapping and ensure the pilot hole is drilled to the correct tap-drill diameter for a 1/4-28 UNF thread. Use a thread-cutting lubricant appropriate for steel to extend tool life and protect thread quality. Spiral point taps are not recommended for blind-hole applications where chip packing is a concern.