Hertel G837583 Extension Tap 1/4-28 Unf 4 Flute Hss

Product Description

The HERTEL G837583 is a high speed steel extension tap designed for cutting 1/4-28 UNF internal threads in a range of workpiece materials. Built to an H3 thread limit with a plug chamfer, it provides controlled thread tolerance suited to general-purpose tapping applications where precise fit is required. The 4-flute design offers chip clearance and thread engagement across the full 6-inch overall length. The bright, uncoated finish is appropriate for use with standard cutting fluids. This tap is intended for machinists, maintenance technicians, and toolroom professionals working with manually operated or CNC tapping equipment.

This extension tap is suited for applications requiring greater reach into deep holes or recessed bosses where a standard-length tap cannot achieve full thread depth. The 3B class of fit designation makes it appropriate for standard tolerance threaded assemblies in light industrial, mechanical, and maintenance repair operations. The reduced shank diameter supports use in chucks and collets sized below the thread diameter, expanding toolholder compatibility in confined setups.

Key Features

• 1/4-28 UNF thread form with H3 thread limit for controlled tolerance
• Plug chamfer with 4 flutes for balanced chip flow during tapping
• 6-inch overall length provides extended reach for deep or recessed holes
• High speed steel construction for general-purpose cutting performance
• Bright, uncoated finish compatible with standard tapping fluids
• Reduced shank diameter at 0.185 inches for flexible toolholder fitment

Compatibility

Designed as a standard replacement or production tap for 1/4-28 UNF threaded applications requiring a 3B class of fit in general machining and maintenance environments.

Installation Notes

This tap should be installed by a qualified machinist or toolroom technician using appropriate tap holders or floating collet chucks. Ensure the workpiece is securely fixtured and properly lubricated with a suitable cutting fluid before tapping. Do not force the tap through a hole that has not been drilled to the correct tap drill size for 1/4-28 UNF. Inspect the tap for wear or chipping before each use to avoid thread damage or tap breakage.