Osg 2930608 Spiral Flute Tap 5/16-18 Unc Ticn Vanadium Hss

Product Description

The OSG 2930608 is a spiral flute tap designed for cutting 5/16-18 UNC right-hand internal threads in a wide range of metallic workpiece materials. Built from vanadium high-speed steel with a titanium carbonitride (TiCN) coating, this tap delivers improved wear resistance and lubricity compared to uncoated HSS tooling. The modified bottoming chamfer allows threading closer to the bottom of blind holes than a standard plug tap. With a 45-degree helix angle and 3 right-hand flutes, the design promotes efficient chip evacuation in through-hole and semi-blind applications. Overall length is 3.594 inches. It belongs to OSG Series 290 and carries an H2 thread limit for controlled fit tolerances. Installation is by hand tap wrench or machine tapping on CNC or drill press setups.

This tap is suited for production and maintenance tapping in alloy steel, carbon steel, cast iron, stainless steel, die steel, and hardened steel. The TiCN coating makes it particularly effective in abrasive or work-hardening materials where uncoated taps wear prematurely. Typical applications include threading fastener holes in machined components, fixturing, tooling plates, and general fabrication work. The modified bottoming chamfer is especially useful in blind-hole tapping where full thread depth close to the bottom of the hole is required. This tool is sold individually and is compatible with standard 5/16-inch tap holders and collet-style tool holders.

Key Features

• 5/16-18 UNC thread form with H2 thread limit for controlled tolerance fit
• TiCN coating improves surface hardness and reduces friction for longer tool life in abrasive materials
• Vanadium high-speed steel substrate provides toughness in interrupted cuts and hard materials
• 45-degree right-hand spiral flutes promote upward chip evacuation in blind and semi-blind holes
• Modified bottoming chamfer allows threading closer to the bottom of blind holes than plug-style chamfer
• Right-hand thread direction; no coolant-through feature required for standard tapping operations

Compatibility

Designed for use in alloy steel, carbon steel, cast iron, stainless steel, die steel, and hardened steel workpieces. Fits standard tap wrenches and machine tap holders sized for 5/16-inch taps with a 0.429-inch shank diameter.

Installation Notes

This tap is installed by machinists and toolroom professionals using a hand tap wrench, tapping head, or rigid machine tapping setup on a drill press, mill, or CNC machining center. Ensure the workpiece is securely fixtured and the pilot hole is drilled to the correct tap drill diameter for 5/16-18 UNC threads before tapping. Apply appropriate cutting fluid for the workpiece material, particularly when tapping stainless or hardened steel. Do not force the tap if resistance increases suddenly - back off to break chips and re-apply cutting fluid to avoid tap breakage.