Osg 1765501 Extension Tap 1/2-13 Unc Spiral Point Vanadium Hss

Product Description

The OSG 1765501 is a spiral point plug extension tap designed for threading 1/2-13 UNC holes in metalworking applications. Built from vanadium high-speed steel with a steam oxide finish, it provides wear resistance and lubricity during cutting. The plug chamfer style makes it well suited for through-hole threading operations. With an overall length of 6 inches and a reduced shank diameter of 0.367 inches, this tap reaches into deeper workpiece setups that a standard-length tap cannot access. The H3 thread limit holds close tolerances for 3B class of fit threads. Three right-hand flutes and a right-hand helix push chips forward ahead of the tap during the cut.

This tap is used in machine shop, maintenance, and fabrication environments where threading into carbon steel, hardened steel, or stainless steel is required. The extension length is useful when threading recessed bosses, deep flanges, or other features where a standard tap length would not reach the thread start. It is designed for use in CNC machining centers, drill presses, and tapping machines where the longer reach is necessary without sacrificing rigidity from the reduced shank profile.

Key Features

• Spiral point (gun tap) design pushes chips forward for clean through-hole threading
• Vanadium high-speed steel construction for durability in carbon steel, hardened steel, and stainless steel
• Steam oxide finish reduces friction and improves chip flow
• H3 thread limit for accurate 3B class of fit tolerance control
• 6 inch overall length with reduced shank for extended reach applications
• Plug chamfer style for through-hole starting and threading

Compatibility

Designed for threading 1/2-13 UNC right-hand threads in carbon steel, hardened steel, and stainless steel workpieces. Suitable for use with standard 1/2-13 tapping chucks and extension holders that accept a 0.367 inch shank diameter.

Installation Notes

Extension taps are installed and operated by qualified machinists using appropriate tapping chucks, floating holders, or rigid tapping setups on machine tools. Ensure the workpiece is securely clamped and the tap is correctly aligned to the pilot hole before initiating the cut. Use cutting fluid appropriate for the workpiece material to extend tap life and improve thread finish. Inspect the tap for wear or chipping before each use and replace when cutting performance degrades.