Guhring 9039020222250 Spiral Point Tap 7/8-14 Unf 4 Flutes

Product Description

The GUHRING 9039020222250 is a spiral point tap designed for right-hand through-hole threading in steel and similar ferrous materials. Built from HSS-E cobalt high-speed steel, this tap delivers increased heat resistance and wear life compared to standard HSS tooling. It carries a 7/8-14 UNF thread specification with a plug chamfer for controlled entry and features a 4-flute geometry that pushes chips forward ahead of the cutting zone, making it suited for through-hole applications where chip evacuation is critical. Overall length is 4.689 inches with a thread length of 0.875 inches and a shank diameter of 0.697 inches.

This tap is intended for threading through-holes in steel workpieces in both production machining and maintenance repair environments. The plug chamfer provides a gradual lead-in that distributes cutting forces across several threads, reducing the risk of tap breakage in tougher materials. Thread limit is H6/H7, and the class of fit is 2B, making it appropriate for standard UNF fastener assemblies requiring a free-running to close fit. It belongs to GUHRING Series 3902 and is sold individually. Coolant-through capability is not included in this design.

Key Features

• HSS-E cobalt construction for extended tool life in steel applications
• Spiral point geometry pushes chips forward for reliable through-hole performance
• Plug chamfer distributes cutting load across the lead threads
• 4-flute design provides rigidity and consistent thread form
• H6/H7 thread limit suits 2B class-of-fit requirements
• Bright/uncoated finish — no added coating thickness to affect thread tolerance

Compatibility

Designed for through-hole threading operations producing 7/8-14 UNF 2B internal threads in steel. Verify spindle speed, feed rate, and fixturing against the workpiece material and machine specifications before use.

Installation Notes

This tap is intended for use by machinists and maintenance technicians operating drill presses, CNC machining centers, or tapping machines. Ensure the workpiece is securely fixtured and the spindle is properly aligned before engaging the tap. Use an appropriate cutting fluid rated for tapping steel to extend tool life and maintain thread quality. Inspect the tap for wear or damage before each use and replace if cutting edges show signs of dulling or chipping.