Hertel K008346AS Straight Flute Tap 1/4-28 Unf Hss

Product Description

The HERTEL K008346AS is a straight flute tap designed for cutting internal threads in ferrous and non-ferrous materials. Built from high-speed steel with a bright, uncoated finish, it cuts a 1/4-28 UNF right-hand thread with a taper chamfer for easy thread starting. The four-flute configuration provides clean chip evacuation in through-hole and short blind-hole applications. With an overall length of 2.5 inches and a thread length of 1 inch, this tap is sized for standard machine and hand tapping operations. Machinists, tool and die makers, and maintenance technicians use this tap for production and repair threading work.

This tap is suited for threading 1/4-28 UNF holes in general manufacturing, maintenance, and repair applications. The taper chamfer — typically 8 to 10 threads of lead — makes it the preferred choice for starting threads in through-holes or for the initial pass in a two-tap sequence. It performs well in steel, cast iron, aluminum, and similar machinable materials. The H2 thread limit provides a controlled fit tolerance appropriate for most standard UNF fastener assemblies.

Key Features

• 1/4-28 UNF thread form, right-hand direction
• Taper chamfer for controlled thread starting
• 4 straight flutes for efficient chip removal in through-hole applications
• High-speed steel construction for durability across a range of machinable materials
• H2 thread limit for standard tolerance UNF fits
• Bright, uncoated finish — no coating buildup concerns for light to moderate duty use

Compatibility

Designed as an OEM-style replacement or standard shop tap for any application requiring a 1/4-28 UNF internal thread in through-hole or short blind-hole configurations.

Installation Notes

A licensed machinist or experienced maintenance technician should verify proper tap drill size before threading — the correct drill produces the required minor diameter for a 1/4-28 UNF thread. Use cutting fluid appropriate for the workpiece material to extend tap life and improve thread finish. Always back off periodically when hand tapping to break chips and prevent tap breakage. Secure the workpiece fully before applying torque to avoid misalignment or tap breakage.