Guhring 9039950063500 Spiral Flute Tap 1/4-28 Unf Tin

Product Description

The GUHRING 9039950063500 is a spiral flute tap designed for blind hole threading in demanding metalworking applications. It features a 1/4-28 UNF thread form with a modified bottoming chamfer, allowing it to thread closer to the bottom of a blind hole than a standard plug tap. Built from powdered metal and coated with TiN (titanium nitride), this tap delivers extended tool life when cutting heat treatable hardened steel, high tensile steel, and tool steel. The 40-degree helix angle and fast flute style promote efficient chip evacuation in deep or tight blind holes. Overall length is 3.15 inches with a 0.255-inch shank diameter.

This tap is suited for production and maintenance machining environments where tight thread tolerances and consistent results are required in hard or high-tensile ferrous materials. The H3/H4 thread limit and 2B class of fit make it appropriate for standard fastener thread applications. It is typically used by machinists and tool and die professionals working on CNC machining centers, drill presses, and manual tapping operations where blind hole access demands a modified bottoming style tool.

Key Features

• Modified bottoming chamfer for threading close to the bottom of blind holes
• TiN coating improves wear resistance and reduces friction when tapping hardened and high tensile steels
• Powdered metal construction provides higher hardness and toughness compared to standard HSS
• 40-degree helix angle with fast flute style promotes reliable chip evacuation in blind hole applications
• H3/H4 thread limit supports 2B class of fit for standard UNF threaded fastener assemblies
• Right hand flute and right hand thread for conventional tapping operations

Compatibility

Designed for blind hole threading in heat treatable hardened steel, high tensile steel, and tool steel. Produces 1/4-28 UNF right hand threads to a 2B class of fit. Compatible with standard tap holders and collets accepting a 0.255-inch shank diameter.

Installation Notes

Installation and use should be performed by a qualified machinist following applicable shop safety procedures. Power down and de-energize any machine tool before securing or changing the tap in a holder. Use an appropriate cutting fluid or lubricant recommended for the workpiece material to extend tool life and maintain thread quality. Do not exceed the recommended speed and feed range for powdered metal taps in hardened steel, as overloading can cause tap breakage in blind holes.