Hertel K008591AS Spiral Flute Tap 3/4-10 Unc 4 Flute Hss

Product Description

The HERTEL K008591AS is a spiral flute tap designed for threading 3/4-10 UNC holes in a wide range of metalworking applications. Built from high speed steel with a bright, uncoated finish, this plug chamfer tap features four right-hand flutes with a 52-degree helix angle that efficiently evacuates chips upward during through-hole tapping operations. The H3 thread limit provides a controlled fit tolerance suitable for standard UNC fastener assemblies. At 4.25 inches overall length and a 0.590-inch shank diameter, it fits standard tap holders and machine spindles used in production and maintenance machining environments. Licensed machinists and tool-and-die technicians are the primary users of this tap.

This tap is well suited for through-hole tapping in materials such as aluminum, mild steel, and other free-machining metals where chip evacuation is a priority. The spiral flute design pulls chips away from the cutting edge during the threading pass, reducing the risk of chip packing and tap breakage. It is commonly used in CNC machining centers, drill presses, and manual tapping arms for both production runs and low-volume repair work. The plug chamfer allows the tap to start easily in a pre-drilled hole and thread progressively to depth.

Key Features

• 3/4-10 UNC thread form with right-hand thread and right-hand flute direction
• 52-degree helix angle promotes upward chip evacuation ideal for through-hole applications
• H3 thread limit for controlled tolerance fit in standard UNC assemblies
• High speed steel construction provides good wear resistance across common workpiece materials
• Plug chamfer for progressive thread engagement and easy hole starting
• Bright, uncoated finish suitable for use with cutting fluids or tapping compounds

Compatibility

Designed as an OEM-style cutting tool for use in standard 3/4-10 UNC tapping applications where a plug chamfer spiral flute tap with H3 thread limit is specified.

Installation Notes

This tap is installed by qualified machinists using standard tap holders, collet chucks, or floating tap adapters sized for the 0.590-inch shank diameter. Always secure the workpiece firmly and ensure the pilot hole is drilled to the correct tap drill diameter for 3/4-10 UNC before threading. Apply an appropriate cutting fluid or tapping compound to extend tool life and improve thread finish. Back the tap off periodically to break chips when tapping in blind holes, though the spiral flute design is optimized for through-hole work.