Osg 2931501 Spiral Flute Tap 3/8-16 Unc Vanadium Hss

Product Description

The OSG 2931501 is a spiral flute tap designed for cutting 3/8-16 UNC right-hand internal threads in a wide range of ferrous materials. Built from 3% vanadium high-speed steel and finished with a steam oxide coating, this tap offers improved wear resistance and reduced friction during threading operations. The 45-degree helix angle drives chips up and out of the hole, making it well suited for blind-hole applications where chip evacuation is critical. The modified bottoming chamfer allows threading closer to the bottom of a hole than a standard plug tap. With an overall length of 3.156 inches and a shank diameter of 0.323 inches, this tool fits standard tap holders and machine spindles used in production and maintenance environments.

This tap is intended for threading operations in alloy steel, carbon steel, cast iron, stainless steel, die steel, and hardened steel. The H2 thread limit provides a controlled tolerance class appropriate for standard UNC fit requirements. It is used in machine shop production, maintenance and repair operations, and toolroom applications where accurate, repeatable thread quality is required. The tap is run without coolant-through capability, making it compatible with external flood or manual lubrication setups.

Key Features

• 3/8-16 UNC right-hand thread form with H2 thread limit for controlled tolerance fit
• 45-degree spiral flute helix for efficient upward chip evacuation in blind holes
• Modified bottoming chamfer for threading near the bottom of blind holes
• 3% vanadium high-speed steel construction for elevated wear resistance
• Steam oxide coating reduces friction and provides mild corrosion protection
• Compatible with alloy steel, carbon steel, cast iron, stainless steel, die steel, and hardened steel

Compatibility

Designed for use in alloy steel, carbon steel, cast iron, stainless steel, die steel, and hardened steel workpieces requiring 3/8-16 UNC right-hand internal threads. Part of the OSG Series 290 spiral flute tap line.

Installation Notes

This tap is installed and operated by a machinist or toolroom technician using a standard tap holder, tapping head, or CNC machine spindle. Ensure the workpiece is securely fixtured and the pilot hole diameter is correct for the H2 thread limit before beginning the tapping cycle. Apply an appropriate cutting fluid compatible with the workpiece material to extend tool life. Do not exceed the tap's rated cutting speed for the material being threaded, and reverse the tap periodically in manual operations to break chips.