Hertel K011005AS Hand Tap 4-40 Unc Plug 3-flute Hss

Product Description

The HERTEL K011005AS is a straight-flute hand tap designed for cutting 4-40 UNC internal threads in a wide range of materials. Built from high speed steel with a bright, uncoated finish, this tap delivers consistent thread form in light-duty tapping applications. The plug chamfer — typically 3 to 5 threads — allows the tap to start easily in through-holes while providing adequate guidance. With a thread limit of H4, this tool produces threads in the upper tolerance range of the 4-40 UNC class, making it suitable for applications that require a slightly looser fit for plating or coating allowance. Overall length is 1.875 inches with a shank diameter of 0.141 inches.

This tap is suited for machinists, tool and die technicians, and maintenance professionals working with small-diameter fastener threads in ferrous and non-ferrous metals, plastics, and similar materials. The 4-40 UNC designation is a common thread size found in electronics enclosures, instrument panels, and light mechanical assemblies. The 3-flute straight-flute design performs well in through-hole applications where chip evacuation is straightforward. A plug chamfer makes this tap the standard choice for general-purpose tapping when a bottoming tap is not required.

Key Features

• 4-40 UNC thread form with H4 thread limit for controlled upper-tolerance fit
• Plug chamfer for easy starting in through-holes
• 3-flute straight-flute geometry supports chip flow in general-purpose tapping
• High speed steel construction provides wear resistance across a broad range of workpiece materials
• Bright, uncoated finish for use with cutting fluid on a variety of materials
• Compact 1.875-inch overall length suited to hand tapping and small machine setups

Compatibility

Designed as an OEM-style hand tap for use in standard 4-40 UNC tapping applications across general machining, maintenance, and light manufacturing environments.

Installation Notes

This tap is intended for use by machinists or maintenance technicians familiar with hand tapping procedures. Always use an appropriate cutting fluid for the workpiece material and back off periodically to break chips. Ensure the tap is started square to the hole to prevent breakage, especially at this small diameter. Do not apply excessive torque — 4-40 taps are susceptible to breakage if overdriven.