Hertel K008084AS Straight Flute Tap 4-40 Unc Hss

Product Description

The HERTEL K008084AS is a straight flute tap designed for cutting 4-40 UNC internal threads in a variety of metalworking and machining applications. Built from high-speed steel with a bright/uncoated finish, this tap features a taper chamfer that helps align and start the thread accurately at entry. It runs a 3-flute configuration, which provides good chip clearance in through-hole applications. The H1 thread limit designation indicates a tight tolerance class suited to standard fastener fits. At 1.875 inches overall length with a 0.562-inch thread length, this is a compact tap intended for small-diameter work where precision matters.

This tap is used primarily in machine shops, maintenance and repair operations, and production environments where 4-40 UNC threaded holes are required. Typical applications include tapping holes in aluminum, mild steel, brass, and similar free-machining materials. The taper chamfer makes it well suited for starting threads in through holes. It is commonly used by machinists, tool-and-die technicians, and MRO professionals working on small assemblies, enclosures, and electronic hardware that require UNC miniature fastener threads.

Key Features

• 4-40 UNC thread form in a compact 1.875-inch overall length
• High-speed steel construction for durability across common shop materials
• Taper chamfer for easy thread starting and alignment in through holes
• 3 straight flutes for chip clearance in non-interrupted cuts
• H1 thread limit for close-tolerance standard fastener fits
• Bright/uncoated finish — no coating buildup to affect thread dimensions

Compatibility

Designed as a standard replacement or production tap for 4-40 UNC through-hole threading operations in general machining and MRO applications.

Installation Notes

This tap is intended for use by machinists and qualified shop personnel using a tapping machine, drill press, or hand tap wrench with proper alignment. Always drill the correct tap drill size before tapping and ensure the workpiece is securely fixtured. Apply appropriate cutting fluid to extend tool life and reduce galling, especially in steel. Do not force or back-tap beyond the thread length, as the small 4-40 diameter is susceptible to breakage under side load or torque overload.