Osg 2906408 Spiral Flute Tap 4-40 Unc Ticn Vanadium Hss

Product Description

The OSG 2906408 is a spiral flute tap designed to cut 4-40 UNC internal threads in a wide range of ferrous and engineered materials. Built from vanadium high-speed steel and finished with a TiCN coating, this tap delivers improved wear resistance and extended tool life compared to uncoated alternatives. The 45-degree helix angle evacuates chips upward out of the hole, making this geometry well-suited for blind-hole applications where chip packing is a concern. The modified bottoming chamfer allows threading close to the bottom of a blind bore. Machinists and toolroom technicians working on small-diameter threaded fastener features will find this tool appropriate for production and maintenance applications alike.

The OSG 2906408 is rated for use in alloy steel, carbon steel, cast iron, stainless steel, die steel, and hardened steel. Its H2 thread limit and 2B/3B class of fit make it suitable for standard UNC fastener engagement in both general-purpose and close-tolerance assemblies. It is commonly used in CNC machining centers, drill presses, and tapping arms where small-diameter precision threads are required in ferrous workpieces across aerospace, tooling, and general manufacturing environments.

Key Features

• Vanadium high-speed steel construction for improved toughness and wear resistance
• TiCN coating reduces friction and extends tool life in ferrous materials
• 45-degree right-hand spiral flute geometry promotes upward chip evacuation in blind holes
• Modified bottoming chamfer enables threading near the base of blind bores
• H2 thread limit with 2B/3B class of fit for standard UNC fastener applications
• No coolant-through requirement — compatible with flood or mist coolant delivery

Compatibility

Designed for cutting 4-40 UNC threads in alloy steel, carbon steel, cast iron, stainless steel, die steel, and hardened steel workpieces. Part of the OSG Series 290 spiral flute tap line.

Installation Notes

This tap is installed by machinists and toolroom technicians using a tapping chuck, CNC rigid tapping cycle, or a manual tapping arm. Ensure the workpiece is securely fixtured and the pilot hole diameter is correct for the 4-40 UNC thread form before beginning the tapping operation. Use an appropriate cutting fluid or flood coolant for the workpiece material to maximize tool life and thread quality. Do not force the tap if resistance is felt — back off to clear chips before continuing.