Guhring 9039010222250 Spiral Point Tap 7/8-9 Unc Hss-e

Product Description

The GUHRING 9039010222250 is a spiral point tap designed for through-hole threading in steel and similar materials. Built from HSS-E cobalt high-speed steel, it delivers the hardness and heat resistance needed for production tapping in tough ferrous stock. The 7/8-9 UNC thread profile with a plug chamfer and 4-flute spiral point geometry pushes chips forward through the hole, keeping the flutes clear and reducing the risk of tap breakage. This tap holds a 2B class of fit and a H6/H7 thread limit, making it suitable for standard commercial-tolerance fastener holes. Machinists and tool-and-die trades use this tap in CNC tapping operations and manual tapping heads alike.

This tap is intended for right-hand through-hole threading applications in steel workpieces. The plug chamfer provides a gradual lead-in that distributes cutting forces across the first few threads, making it well suited for production runs where consistent thread quality matters. With a thread length of 2.625 inches and an overall length of 4.689 inches, it fits standard tap holders used in CNC machining centers, drill presses, and manual tapping fixtures. The Series 3901 designation places it within GUHRING's standard spiral point tap product line. No coolant-through feature is present, so external cutting fluid or tapping compound application is the standard practice.

Key Features

• HSS-E cobalt construction for improved heat resistance and tool life in steel applications
• Spiral point geometry pushes chips forward, reducing chip packing in through-hole operations
• Plug chamfer distributes cutting load across multiple lead threads for consistent engagement
• 2B class of fit with H6/H7 thread limit meets standard commercial fastener hole tolerances
• Bright/uncoated finish — compatible with a wide range of tapping fluids and coolants
• Right-hand thread direction for use with standard tapping heads and holders

Compatibility

Designed for through-hole threading of 7/8-9 UNC fastener holes in steel and similar ferrous materials. Fits standard tap holders accepting a 0.697-inch shank diameter.

Installation Notes

Installation and use should be performed by qualified machinists following shop safety protocols. Secure the workpiece firmly before tapping and ensure the tap is aligned perpendicular to the hole to prevent thread misalignment or tap breakage. Apply an appropriate cutting fluid or tapping compound throughout the operation to reduce heat buildup and extend tool life. Inspect the tap for wear or chipping between production runs.