Osg 1105611708 Spiral Point Tap 5/16-18 Unc Ticn

Product Description

The OSG 1105611708 is a spiral point tap designed for threading 5/16-18 UNC holes in demanding materials including hardened steel, stainless steel, high-nickel alloy, titanium, and alloy steel. Built from powdered metal with a TiCN coating, this tap delivers superior wear resistance and heat tolerance compared to standard HSS tooling. The plug chamfer style allows it to start threads progressively, making it well suited for through-hole applications. With an H3 thread limit and a 3B class of fit, it produces threads that meet standard tolerance requirements for general mechanical assemblies. Three flutes provide efficient chip evacuation ahead of the cutting edge during the tapping operation.

This tap is intended for use in CNC machining centers, drill presses, and tapping machines where right-hand threading is required. The 5/16-18 UNC designation makes it a common choice for fastener holes in industrial equipment, structural assemblies, and mechanical components across manufacturing and maintenance environments. It is typically used by machinists, tool and die makers, and maintenance technicians working with ferrous and high-alloy workpieces. The Series 312TI designation places it within OSGs TiCN-coated powdered metal tap line, optimized for difficult-to-machine materials where standard coatings fall short.

Key Features

• TiCN coating increases surface hardness and reduces friction for extended tool life in abrasive materials
• Powdered metal substrate provides finer grain structure and greater toughness than conventional HSS
• Plug chamfer style for progressive thread engagement in through-hole applications
• H3 thread limit with 3B class of fit for standard tolerance threading
• Three flutes promote forward chip evacuation, reducing recutting in through-hole operations
• Right-hand thread direction compatible with standard tapping equipment

Compatibility

Designed for threading 5/16-18 UNC right-hand threads in hardened steel, stainless steel, high-nickel alloy, titanium, and alloy steel workpieces. Suitable for use in manual and CNC tapping operations requiring H3 thread limit and 3B class of fit.

Installation Notes

This tap should be installed in a tap holder or collet that provides axial float to prevent thread distortion during machine tapping. Always ensure the workpiece is securely fixtured and the pilot hole diameter is correct for 5/16-18 UNC before starting. Use an appropriate cutting fluid for the workpiece material, particularly when tapping stainless or high-nickel alloys, to reduce heat buildup and extend tap life. Inspect the tap for chipping or wear before each use and replace when cutting torque increases noticeably.