Guhring 9039780111130 Spiral Flute Tap 7/16-20 Unf

Product Description

The GUHRING 9039780111130 is a spiral flute tap designed for blind hole threading in steel and alloyed steel workpieces. It cuts a 7/16-20 UNF right-hand internal thread to a 2B class of fit, which meets standard fastener assembly tolerances. The tap is manufactured from cobalt high-speed steel and carries a TiN (titanium nitride) coating to reduce friction and extend tool life in demanding cutting conditions. With a 40-degree helix angle and a fast flute style, it evacuates chips efficiently from the bottom of a blind bore. Overall length is 3.157 inches. Licensed machinists and toolroom technicians are the primary users.

This tap is suited for production and maintenance threading operations in ferrous materials including unalloyed steel and alloyed steel. The bottoming chamfer allows threading to within a few pitches of the bottom of a blind hole, making it the correct choice when full thread depth close to the bottom of a bore is required. The H4 and H5 thread limits support typical clearance fits used in precision assembly applications. It is appropriate for use on CNC machining centers, knee mills, and drill presses equipped with a tapping head or rigid tapping cycle.

Key Features

• Bottoming chamfer for full thread depth in blind holes
• Cobalt HSS construction for heat and wear resistance in alloyed steels
• TiN coating reduces friction and extends tool life
• 40-degree helix angle with fast flute style for efficient chip evacuation
• H4 and H5 thread limits for 2B class of fit compliance
• Right-hand flute and right-hand thread configuration

Compatibility

Designed for blind hole threading in unalloyed steel and alloyed steel. Compatible with standard 7/16-inch tap holders and quick-change tapping chucks accepting a 0.323-inch shank diameter with a 0.242-inch square drive. Series 3978.

Installation Notes

Installation is performed by qualified machinists following standard tapping procedures. Secure the workpiece and ensure the pre-drilled hole diameter matches the recommended tap drill size for a 7/16-20 UNF thread before starting. Use a compatible cutting fluid or tapping compound appropriate for steel to prevent galling and premature wear. Verify spindle alignment and use rigid tapping or a floating holder to avoid thread form errors and tap breakage.