Osg 1295400 Extension Tap 7/16-14 Spiral Point Hss

Product Description

The OSG 1295400 is a spiral point plug extension tap designed for threading operations that require greater reach than a standard-length tap provides. Built from high speed steel with a bright uncoated finish, this tap is intended for right-hand UNC threads at 7/16-14 and carries an H3 thread limit with a 3B class of fit. The overall length of 6 inches and a reduced shank give it the extended reach needed to thread deep holes or recessed features. With 3 flutes and a spiral point geometry, it pushes chips forward ahead of the cut, making it well suited for through-hole tapping in production environments.

This tap is applied in machining and fabrication work where standard-length taps cannot reach the thread zone. It is compatible with aluminum, carbon steel, cast iron, and hardened steel workpieces. The plug chamfer style makes it appropriate for through-hole applications rather than blind holes. Machinists, toolroom technicians, and maintenance professionals working in job shops, manufacturing facilities, or field repair settings will find this tap fits common manual and CNC tapping setups. The 7/16-14 UNC thread form is a widely used coarse thread standard in structural and mechanical assemblies.

Key Features

• Spiral point geometry pushes chips forward, reducing chip packing in through-hole tapping
• H3 thread limit provides controlled tolerance for 3B class of fit applications
• Extended 6-inch overall length with reduced shank for reaching deep or recessed holes
• High speed steel construction handles aluminum, carbon steel, cast iron, and hardened steel
• Plug chamfer suits through-hole threading applications
• Bright uncoated finish allows straightforward inspection and reconditioning

Compatibility

Designed as an OEM-style replacement or direct-use extension tap for 7/16-14 UNC through-hole tapping operations across aluminum, carbon steel, cast iron, and hardened steel workpieces.

Installation Notes

Extension taps are installed and operated by machinists or maintenance technicians using standard tap holders, extension holders, or CNC tapping chucks sized to the reduced shank diameter. Ensure the workpiece is securely fixtured and the tap is aligned perpendicular to the hole before starting the thread. Use appropriate cutting fluid for the workpiece material to extend tool life and improve thread quality. Inspect the tap for wear or chipping before each use, as a damaged cutting edge can produce out-of-tolerance threads.