Osg 1765001 Extension Tap 1/4-20 Spiral Point Vanadium Hss

Product Description

The OSG 1765001 is a spiral point plug extension tap designed for threading operations in ferrous and stainless materials. Built from vanadium high-speed steel and finished with a steam oxide coating, it handles carbon steel, hardened steel, and stainless steel applications. The tap cuts a 1/4-20 UNC right-hand thread to a 3B class of fit, making it suitable for precision threaded assemblies that require close tolerance. At 6 inches overall length, it reaches deeper into workpieces or fixtures than a standard-length tap, which is its primary advantage over a conventional jobber-length tool. Three flutes with a spiral point geometry push chips forward ahead of the tap, keeping the flutes clear in through-hole applications.

This tap is used in machining, fabrication, and maintenance operations where standard-reach taps cannot access the thread location. The extended overall length and reduced shank allow it to reach recessed bosses, deep counterbores, and confined areas on structural assemblies and mechanical components. It is suited for use in vertical mills, drill presses, and CNC tapping operations where a 1/4-20 UNC thread is required. The spiral point plug chamfer means it is intended for through-hole threading rather than blind-hole work.

Key Features

• Spiral point plug geometry drives chips forward for clean through-hole tapping
• Vanadium high-speed steel construction for improved wear resistance on carbon steel, hardened steel, and stainless steel
• Steam oxide finish reduces friction and provides light corrosion resistance during storage and use
• H3 thread limit provides controlled oversize tolerance for reliable fit in 3B class threads
• Reduced shank diameter allows use in standard tap holders while extending reach into confined areas
• 6 inches overall length with 1.5 inches neck length for deep-reach threading applications

Compatibility

Designed for through-hole threading of 1/4-20 UNC fastener threads in carbon steel, hardened steel, and stainless steel workpieces. Fits standard tap holders and tapping chucks that accept a 0.255 inch shank diameter with a 0.191 inch square drive.

Installation Notes

This tap should be installed and operated by a machinist or maintenance technician familiar with tapping speeds and feeds for the workpiece material. Always secure the workpiece completely and ensure the tap is aligned perpendicular to the hole before engaging. Use appropriate cutting fluid for the material being tapped, particularly when working stainless steel. Inspect the tap for chipping or wear before each use, as a damaged tap can seize in the hole and cause workpiece damage.