Osg 1651502208 Spiral Point Tap 5/16-24 Unf 3 Flute

Product Description

The OSG 1651502208 is a high-performance spiral point tap designed to cut 5/16-24 UNF internal threads in through-hole applications. Built from powdered metal (grade PMT15) and coated with TiCN for extended tool life, it features a plug chamfer that gradually engages the workpiece to reduce chipping and tap breakage. The 3-flute spiral point geometry pushes chips forward through the hole, making it well-suited for production environments where chip evacuation is critical. With an overall length of 3.543 inches and a thread length of 0.661 inches, this tap fits standard tap holders and is sized for 5/16-inch work. Right-hand thread direction and a 2B class of fit ensure compatibility with standard UNF thread gages. This tool is installed by machinists, toolroom techs, and maintenance professionals working with threaded fastener applications.

The 1651502208 is rated for use across a broad range of workpiece materials including low-carbon, medium-carbon, high-carbon, and alloy steels, as well as cast iron, stainless steel, die steel, aluminum, cast aluminum, and hardened steel. It is appropriate for CNC machining centers, manual tapping machines, and hand-tapping setups where a plug-style entry is preferred for starting in a drilled through-hole. The H4 thread limit designation targets a tolerance range suitable for standard 2B UNF fits without oversize compensation. No coolant-through feature is present, so external flood or mist coolant delivery should be used when machining harder or gummier materials.

Key Features

• 5/16-24 UNF right-hand thread form with 2B class of fit and H4 thread limit
• Powdered metal (PMT15) substrate for improved wear resistance over standard HSS
• TiCN coating reduces friction and extends tool life in ferrous and non-ferrous materials
• 3-flute spiral point design pushes chips ahead of the tap in through-hole cutting
• Plug chamfer provides gradual thread engagement and reduces tap breakage risk
• No coolant-through bore - compatible with external flood or mist coolant setups

Compatibility

Rated for use in alloy steel, aluminum, cast aluminum, cast iron, hardened steel, high-carbon steel, low-carbon steel, medium-carbon steel, stainless steel, and die steel. Part of OSG Series 16515.

Installation Notes

This tap should be installed by a qualified machinist or toolroom technician using a properly sized tap holder or collet chuck. Ensure the spindle and workpiece are secured before beginning the tapping cycle, and verify the pilot hole diameter matches the recommended tap drill size for 5/16-24 UNF threads. Apply appropriate cutting fluid or external coolant when machining stainless, hardened, or high-carbon steels to prevent galling and premature wear. Do not exceed the recommended cutting speed for the workpiece material, and reverse the tap periodically in manual applications to break chips.