Osg 2935408 Spiral Flute Tap 1/4-28 Unf Ticn Vanadium Hss

Product Description

The OSG 2935408 is a spiral flute tap designed for threading 1/4-28 UNF right-hand internal threads in a wide range of metallic materials. Built from vanadium high-speed steel and finished with a TiCN (titanium carbonitride) coating, this tap delivers enhanced wear resistance and lubricity compared to uncoated HSS tooling. The modified bottoming chamfer allows threading close to the bottom of blind holes. With a 45-degree helix angle and 3 right-hand flutes, the spiral geometry lifts chips upward and out of the hole, reducing the risk of chip packing in interrupted or deep-hole applications. Overall length is 2.5 inches, and the thread limit is H4 with a 2B class of fit for standard commercial tolerance work.

This tap is suited for production and maintenance machining operations where 1/4-28 UNF threads are required in blind or through holes. Compatible material applications include alloy steel, carbon steel, cast iron, stainless steel, die steel, and hardened steel, making it a versatile choice across aerospace, automotive, tooling, and general fabrication environments. The TiCN coating is particularly beneficial when tapping abrasive or harder materials that would rapidly wear uncoated tooling. Machinists, toolmakers, and maintenance technicians working on CNC machining centers, drill presses, or tapping arms will find this tap appropriate for medium to high-volume production runs as well as one-off repair work.

Key Features

• 1/4-28 UNF thread form with H4 thread limit and 2B class of fit for standard commercial tolerance
• 45-degree right-hand spiral flutes promote upward chip evacuation, reducing packing in blind holes
• TiCN coating increases surface hardness and reduces friction for longer tool life in abrasive materials
• Modified bottoming chamfer allows threading near the bottom of blind holes
• Vanadium high-speed steel substrate provides toughness across a wide range of work materials
• No coolant-through requirement - suitable for external flood coolant or cutting oil applications

Compatibility

Rated for use in alloy steel, carbon steel, cast iron, stainless steel, die steel, and hardened steel. Part of OSG Series 290 spiral flute tap lineup.

Installation Notes

Installation should be performed by a qualified machinist or toolmaker following standard tapping practices. Ensure the workpiece is securely fixtured and the tap is properly aligned to the drilled pilot hole before engagement to prevent tap breakage. Apply an appropriate cutting fluid or tapping compound for the work material to improve finish and extend tool life. Inspect the tap for wear or chipping before each use, particularly when working with hardened or abrasive materials.