Osg 1431300 Spiral Flute Tap 7/16-14 Unc Bottoming Hss

Product Description

The OSG 1431300 is a spiral flute bottoming tap designed for cutting 7/16-14 UNC right-hand internal threads in a wide range of ferrous and non-ferrous materials. Built from high-speed steel with a bright uncoated finish, it features three flutes at a 50-degree helix angle that actively eject chips upward out of the hole - the defining advantage of spiral flute geometry in blind-hole applications. The bottoming chamfer allows threading to within one to two threads of the bottom of a blind hole. The H3 thread limit provides a controlled tolerance class appropriate for standard UNC fits. With an overall length of 3.156 inches and a shank diameter of 0.323 inches, this tap seats in standard tap holders and tapping heads used in production and maintenance environments.

This tap is suited for blind-hole tapping operations in aluminum, cast aluminum, cast iron, low-carbon steel, medium-carbon steel, and high-carbon steel. The 50-degree right-hand spiral flute makes it particularly effective in ductile and gummy materials such as aluminum and low-carbon steel, where chip packing in blind holes is a common problem. It fits applications ranging from manual tapping on the bench to CNC machining centers and drill press tapping fixtures where consistent H3 tolerance is required. It is sold individually and is part of OSG Series 107.

Key Features

• 7/16-14 UNC right-hand thread form with H3 thread limit for controlled tolerance
• Bottoming chamfer for threading close to the bottom of blind holes
• 50-degree right-hand spiral flute geometry ejects chips upward out of the cut
• High-speed steel construction handles aluminum, cast iron, and carbon steels
• Bright uncoated finish suitable for use with cutting fluids and tapping compounds
• No coolant-through requirement - compatible with flood or applied cutting fluid

Compatibility

Designed for use in standard tap holders, collet chucks, and tapping heads that accept a 0.323-inch shank diameter; compatible with materials including aluminum, cast aluminum, cast iron, low-carbon steel, medium-carbon steel, and high-carbon steel as stated by the manufacturer.

Installation Notes

This tap should be installed by a machinist or maintenance technician familiar with threading operations and proper tap alignment. Always ensure the workpiece is securely fixtured and the spindle or tap handle is aligned axially with the drilled hole before engaging the tap. Apply an appropriate cutting fluid or tapping compound for the workpiece material - aluminum and cast iron have different lubrication requirements. Back the tap out periodically to break chips if operating manually, and replace the tap at the first signs of torque increase or thread quality degradation to avoid breakage in the blind hole.