Osg 3370516185 Spiral Point Tap 5/16-18 Unc Plug Hr

Product Description

The OSG 3370516185 is a spiral point tap designed for threading 5/16-18 UNC holes in demanding materials including hardened steel, stainless steel, and high-nickel alloys. It features a plug chamfer, three flutes, and an H5 thread limit with a 2B class of fit. The tap is manufactured from powdered metal and carries an HR coating for improved wear resistance and heat tolerance. With an overall length of 3.543 inches and a thread length of 1.25 inches, it is sized for standard through-hole tapping operations. Right-hand cut. Intended for use by machinists and maintenance professionals requiring consistent thread quality in tough material applications.

This tap is suited for production and maintenance tapping in ferrous and high-alloy workpieces. The powdered metal substrate and HR coating make it a practical choice when cutting threads in hardened steel or stainless steel where standard high-speed steel taps wear prematurely. The spiral point geometry pushes chips forward ahead of the tap, making it well suited for through-hole applications where chip evacuation is critical. It belongs to OSG Series 337NI, which is specifically formulated for nickel-bearing and corrosion-resistant alloys.

Key Features

• 5/16-18 UNC thread form with right-hand cut
• Plug chamfer for standard through-hole entry
• Powdered metal construction for enhanced hardness and toughness
• HR coating improves heat resistance and extends tool life in abrasive materials
• Spiral point geometry promotes forward chip ejection in through-hole tapping
• H5 thread limit, 2B class of fit for general-purpose tolerance control

Compatibility

Designed for tapping 5/16-18 UNC through holes in hardened steel, stainless steel, and high-nickel alloys. Part of OSG Series 337NI, engineered for nickel-bearing and corrosion-resistant alloy applications.

Installation Notes

Install in a tapping machine, CNC machining center, or hand tap wrench rated for the tool shank diameter of 0.318 inches. Power down and secure the workpiece before starting. Use appropriate cutting fluid for the material being tapped, particularly when working with stainless steel or nickel alloys, to reduce heat buildup and galling. Do not reverse-feed without disengaging to clear chips in deep applications.