Osg 1720001 Spiral Flute Tap 5/16-18 Unc 3 Flute 2B

Product Description

The OSG 1720001 is a spiral flute tap designed for threading 5/16-18 UNC holes in demanding materials including stainless steel, hardened steel, titanium, and high-nickel alloys. Built from powdered metal with a steam oxide coating, this tap delivers controlled chip evacuation in blind-hole applications where chip packing is a concern. The modified bottoming chamfer allows threading close to the bottom of a hole without sacrificing thread quality. With a 10-degree helix angle and 3 right-hand flutes, it produces clean 2B-class threads in tight tolerances. It is part of OSG Series 313NI, a line engineered specifically for difficult-to-machine alloys.

This tap is suited for precision machining, tool and die, aerospace, and industrial fabrication applications where hard or exotic materials are encountered. It performs in both production and maintenance environments. The modified bottoming chamfer makes it the right choice when threads must extend close to the base of a blind hole. Licensed machinists, toolroom technicians, and CNC operators are the typical users. At 2-23/32 inches overall length and a shank diameter of 0.3180 inches, it fits standard tap holders and CNC tooling systems sized for 5/16-inch taps.

Key Features

• 5/16-18 UNC thread form with 2B class of fit for standard tolerance threaded assemblies
• Spiral flute design evacuates chips upward, reducing packing in blind holes
• Modified bottoming chamfer threads close to hole bottom with minimal incomplete threads
• Powdered metal construction with steam oxide coating improves wear resistance and lubricity
• Rated for stainless steel, hardened steel, titanium, and high-nickel alloys
• H5 thread limit for consistent, repeatable thread sizing in production runs

Compatibility

Designed for use in 5/16-18 UNC blind-hole tapping applications in stainless steel, hardened steel, titanium, and high-nickel alloys. Fits standard tap holders and tapping heads configured for 5/16-inch shank taps.

Installation Notes

Install in a rigid tap holder or CNC tapping head; floating holders may be used where axial compliance is needed for blind holes. Always verify the tap drill size for 5/16-18 UNC per applicable standards before threading. Apply cutting fluid rated for the workpiece material, especially when tapping stainless steel or titanium. Inspect the tap for chipping or wear after use in hardened or high-nickel alloy materials, as these accelerate tool wear.