Osg 1301901203 Spiral Flute Tap 5/16-24 Unf Nitride Hss

Product Description

The OSG 1301901203 is a spiral flute tap designed for cutting 5/16-24 UNF internal threads with a modified bottoming chamfer. Manufactured from vanadium high-speed steel with a nitride coating, it delivers extended tool life in production and maintenance tapping applications. The 3-flute spiral design pulls chips up and out of the hole, making it well suited for blind-hole work. Thread class of fit is 3B with an H3 thread limit, providing controlled tolerance for standard UNF fastener fitment. Overall length is 1.875 inches with a thread length of 0.444 inches.

This tap is rated for use in aluminum and is commonly used in HVAC equipment assembly, pump housings, valve bodies, and other light-metal components that require precise UNF threaded holes. The modified bottoming chamfer allows threading closer to the bottom of blind holes compared to a standard plug chamfer, making it useful in tight-clearance repair and fabrication work. The nitride coating reduces friction and improves wear resistance in production environments. It is sold individually and is a fit for both shop and field toolkits.

Key Features

• 5/16-24 UNF thread form with 3B class of fit and H3 thread limit for controlled tolerance
• Spiral flute geometry pulls chips out of blind holes during tapping
• Modified bottoming chamfer threads closer to hole bottom than plug style
• Vanadium high-speed steel construction for toughness and edge retention
• Nitride coating reduces friction and extends service life in aluminum
• Right-hand thread direction, right-hand flute helix at 50 degrees

Compatibility

Designed for tapping 5/16-24 UNF blind or through holes in aluminum and similar non-ferrous materials. Part of OSG Series 13019.

Installation Notes

Use in a drill press, CNC machine, or hand tap handle with appropriate 5/16-24 UNF tap drill size. Apply cutting fluid rated for the workpiece material before tapping. Secure the workpiece fully before operation and back the tap out periodically to clear chips. Follow applicable shop safety practices and machine guarding requirements.