Guhring 9044094063500 Spiral Flute Tap 1/4-28 Unf

Product Description

The GUHRING 9044094063500 is a spiral flute tap designed for blind hole threading in a wide range of ferrous and non-ferrous materials. Part of the Series 4409 line, it cuts a 1/4-28 UNF right-hand internal thread to a 2B/3B class of fit. The modified bottoming chamfer allows threading close to the bottom of a blind hole, making it well-suited for tight-tolerance applications. Constructed from cobalt high-speed steel and finished with an oxide coating, this tap delivers added wear resistance and lubricity compared to standard HSS tooling. The 40-degree helix angle promotes efficient chip evacuation up and out of the flute channel during the cutting cycle.

This tap is intended for use in drilling and machining operations across industries such as manufacturing, fabrication, and maintenance repair. Rated material applications include alloy steel, alloy tool steel, aluminum alloy, case-hardened steel, cast iron, ductile iron, free-cutting steel, heat-treated steel, malleable cast iron, stainless steel, structural steel, and tool steel. It is suited for use in CNC machining centers, drill presses, and manual tapping setups where a spiral flute geometry is preferred for blind hole work. The H4 thread limit designation indicates the tolerance band for the tapped thread.

Key Features

• Modified bottoming chamfer for threading close to the bottom of blind holes
• Cobalt HSS construction for improved hardness and heat resistance over standard M2 HSS
• Oxide coating reduces friction and improves chip flow
• 40-degree right-hand helix angle promotes chip evacuation in blind hole applications
• 3 flutes, fast flute style for efficient material removal
• H4 thread limit, 2B/3B class of fit for standard and close-tolerance thread requirements

Compatibility

Designed as a Series 4409 OEM-style spiral flute tap for blind hole threading applications requiring a 1/4-28 UNF thread in materials up to and including stainless steel and heat-treated steel.

Installation Notes

Installation is performed by machinists and toolroom technicians using a tapping attachment, rigid tap holder, or manual tap wrench appropriate for the square drive size. Ensure the workpiece is securely clamped and that the pilot hole diameter is correct for the desired thread class before beginning the tapping operation. Apply a compatible cutting fluid or tapping compound recommended for the specific workpiece material to extend tap life and improve thread quality. Do not force the tap if resistance increases unexpectedly; back out to clear chips before continuing.