Hertel K033000AS Spiral Flute Tap 4-40 Unc Hss

Product Description

The HERTEL K033000AS is a spiral flute tap designed to cut 4-40 UNC internal threads in through-holes and blind holes where chip evacuation is critical. Built from high speed steel with a bright, uncoated finish, this plug-chamfer tap suits general-purpose tapping operations across a range of workpiece materials. The right-hand spiral flute geometry at a 52-degree helix angle pulls chips up and out of the hole ahead of the tap, reducing the risk of chip packing in confined bores. It carries a Class of Fit rating of 2B and 3B with an H2 thread limit, making it appropriate for standard fastener-fit applications in production and maintenance environments.

This tap is used in machine shop, toolroom, and maintenance repair operations where 4-40 UNC threads are required. It is well-suited for tapping aluminum, mild steel, brass, and similar materials on drill presses, CNC machining centers, and tapping machines. The plug chamfer provides a gradual lead-in, making it the standard choice for through-hole tapping and for blind holes with adequate thread relief at the bottom. Machinists, tool-and-die makers, and maintenance technicians are the primary users of this tool.

Key Features

• 4-40 UNC thread form with right-hand thread and right-hand spiral flute direction
• 52-degree helix angle promotes efficient chip ejection from the cutting zone
• Plug chamfer provides gradual lead-in suitable for through-hole and most blind-hole applications
• H2 thread limit holds Class 2B and 3B fit tolerances for standard fastener assemblies
• High speed steel construction offers good toughness and wear resistance for general tapping
• Bright, uncoated finish allows visual inspection of tool condition during service

Compatibility

Designed as a standard replacement or production tap for 4-40 UNC through-hole and blind-hole tapping operations in machining and maintenance applications.

Installation Notes

This tap is installed in a tap holder, collet chuck, or dedicated tapping head rated for the tool shank diameter. Always use the correct tap drill size for 4-40 UNC threads and ensure the workpiece is securely fixtured before tapping. Apply appropriate cutting fluid for the workpiece material to extend tool life and improve thread quality. Replace the tap if flute edges show chipping or if thread quality degrades, as running a worn tap risks breakage and scrap.