Hertel G859443 Extension Tap 3/8-24 Hss Spiral Point Plug

Product Description

The HERTEL G859443 is a spiral point plug extension tap designed for cutting right-hand internal threads in metal workpieces. It is built from high speed steel (HSS) and features a bright, uncoated finish. The tap cuts 3/8-24 Unified National Fine (UNF) threads to an H3 thread limit with a 3B class of fit, making it suitable for applications requiring precise thread tolerance control. With an overall length of 6 inches and a reduced shank, this extension tap reaches into deeper or recessed bores that standard-length taps cannot access. It carries 3 flutes and a plug chamfer for general-purpose through-hole and blind-hole tapping in production and maintenance settings. Machinists and tool-and-die tradespeople are the primary users of this tap.

This tap is suited for production machining, maintenance and repair operations, and fabrication environments where 3/8-24 UNF threads are required in steel, aluminum, cast iron, and similar machinable materials. The extended overall length of 6 inches is specifically useful when tapping features in deep housings, fixtures, or assemblies where clearance to the workpiece surface is limited. The spiral point geometry pushes chips ahead of the cutting zone, making it well adapted for through-hole tapping at production feed rates on CNC machining centers, drill presses, and tapping heads.

Key Features

• 3/8-24 UNF thread form with H3 thread limit for controlled tolerance fit
• 3B class of fit for standard precision threaded assemblies
• Spiral point plug geometry pushes chips forward, ideal for through-hole tapping
• 6 inch overall length with reduced shank for extended reach into deep bores
• High speed steel construction provides toughness across a wide range of machinable materials
• Bright, uncoated finish suitable for use with standard cutting fluids

Compatibility

Designed as a standard extension-length spiral point plug tap for 3/8-24 UNF threaded applications in general machining and maintenance environments. Verify spindle collet or chuck capacity accepts the reduced shank diameter before installation.

Installation Notes

This tap should be installed by a qualified machinist or tooling technician using an appropriate tap holder, tapping head, or rigid CNC toolholder. Always apply cutting fluid rated for the workpiece material to extend tool life and maintain thread quality. Ensure the workpiece is securely fixtured and the spindle is properly aligned before starting the cut to prevent tap breakage. Inspect the tap for chipping or wear regularly, especially when working with harder alloys.