Osg 1713501 Spiral Flute Sti Tap 2-56 Unc Vanadium Hss

Product Description

The OSG 1713501 is a spiral flute STI (Screw Thread Insert) tap designed for cutting 2-56 UNC internal threads in preparation for Heli-Coil or similar thread insert installation. Built from vanadium high-speed steel with a steam oxide finish, this tap handles carbon steel, hardened steel, and stainless steel workpieces. The 45-degree helix angle efficiently evacuates chips upward out of blind holes, reducing the risk of chip packing. A modified bottoming chamfer allows threading close to the bottom of a blind hole. The H2 thread limit designation ensures controlled tolerance for consistent insert fitment. This tool is suited for machining, maintenance, and repair operations where thread repair or reinforcement is required.

The OSG 1713501 is used in precision machining and toolroom environments where 2-56 UNC STI threads are needed for thread-insert repairs or original equipment manufacture. Its compact overall length of 1.75 inches and 0.141-inch shank diameter make it compatible with standard tap holders and CNC tooling setups. The 7/16-inch thread length accommodates typical shallow-threaded holes common in small fastener applications. It is appropriate for use on manual lathes, drill presses, and CNC machining centers across both production and repair shop settings.

Key Features

• 2-56 UNC thread form with STI profile for screw thread insert preparation
• 45-degree right-hand spiral flute for upward chip evacuation in blind holes
• Modified bottoming chamfer for threading close to hole bottom
• Vanadium high-speed steel construction for improved wear resistance and toughness
• Steam oxide finish reduces friction and provides light corrosion resistance during use
• H2 thread limit for controlled tolerance fitment with thread inserts

Compatibility

Designed as an STI tap for use with 2-56 UNC screw thread inserts in carbon steel, hardened steel, and stainless steel workpieces per Series 302 specifications.

Installation Notes

This tap should be installed and operated by a machinist or skilled tradesperson familiar with tapping procedures and thread insert systems. Secure the workpiece fully before tapping and use a properly aligned tap holder to avoid tap breakage in small-diameter applications. Apply appropriate cutting fluid for the workpiece material, particularly when tapping stainless or hardened steel. Follow the thread insert system manufacturer specifications for pre-tap drill size to ensure correct minor diameter before using this STI tap.