Osg 1700601 Spiral Point Tap 5/16-18 Unc 3 Flute

Product Description

The OSG 1700601 is a spiral point tap designed for threading through-holes in tough materials. It uses a plug chamfer entry and a 3-flute spiral point geometry to push chips ahead of the cut, keeping the flutes clear during through-hole tapping operations. Built from powdered metal with a steam oxide coating, this tap is suited for demanding applications where standard high-speed steel may wear prematurely. The overall length is 2.72 inches with a thread length of 0.669 inches, and the shank diameter measures 0.318 inches. It carries an H5 thread limit and a 2B class of fit for standard inch-tolerance threaded assemblies. Licensed trades and industrial machinists rely on this series for consistent thread quality in production and maintenance settings.

This tap is rated for use in hardened steel, stainless steel, high-nickel alloy, titanium, alloy steel, and die steel. The 5/16-18 UNC thread size is a common fastener specification across fabrication, maintenance, and repair applications in manufacturing, HVAC equipment assembly, and general mechanical work. The right-hand thread direction matches standard UNC fastener conventions. It is a single-piece tap sold individually and is part of OSG Series 312, a line engineered for performance in difficult-to-machine materials.

Key Features

• Spiral point geometry pushes chips forward, ideal for through-hole tapping
• Powdered metal construction provides increased wear resistance over standard HSS in abrasive and hard materials
• Steam oxide coating reduces friction and provides moderate corrosion resistance during cutting
• H5 thread limit and 2B class of fit for standard UNC tolerance requirements
• No coolant-through requirement simplifies setup in standard machining environments
• Right-hand, non-interrupted thread form for consistent engagement

Compatibility

Designed for through-hole tapping of 5/16-18 UNC threads in hardened steel, stainless steel, high-nickel alloy, titanium, alloy steel, and die steel workpieces. Not intended for blind-hole applications where chip evacuation is restricted.

Installation Notes

This tap is installed and operated by machinists, tool and die makers, and maintenance technicians using a standard tap wrench, tapping head, or CNC machine spindle. Ensure the workpiece is securely fixtured and the pilot hole diameter matches the recommended tap drill size for 5/16-18 UNC before beginning. Apply appropriate cutting fluid for the material being tapped to extend tool life and improve thread finish. Do not reverse the tap under load without first relieving chip pressure, and inspect flutes for wear or damage before reuse.