Osg 1225805 Spiral Point Tap 5/16-18 Unc Tin Hss

Product Description

The OSG 1225805 is a spiral point tap designed for cutting 5/16-18 UNC internal threads in through-hole applications. Built from high-speed steel with a titanium nitride (TiN) coating, it delivers extended tool life and reduced friction compared to uncoated taps. The plug chamfer configuration allows progressive thread engagement over the first few threads, making it well-suited for production tapping in through holes. With 2 flutes and a right-hand thread direction, the 1225805 pushes chips forward ahead of the cut, keeping the flutes clear during operation. Overall length is 2.719 inches with a thread length of 0.724 inches.

This tap is rated for use across a broad range of workpiece materials including aluminum, cast aluminum, cast iron, low-carbon steel, medium-carbon steel, high-carbon steel, and hardened steel. It fits standard production and maintenance tapping operations in machine shops, fabrication facilities, and field service environments where 5/16-18 UNC threads are required. The H2 thread limit designation makes it appropriate for general-purpose tolerance requirements in most standard threaded fastener assemblies.

Key Features

• 5/16-18 UNC thread form with right-hand direction and H2 thread limit
• TiN coating reduces friction and extends tool life across varied material types
• Plug chamfer for progressive engagement in through-hole tapping
• Spiral point geometry pushes chips forward to keep the cutting zone clear
• High-speed steel construction handles a wide range of ferrous and non-ferrous materials
• No coolant-through requirement — compatible with standard flood or manual lubrication

Compatibility

Designed as a direct-fit spiral point tap for 5/16-18 UNC through-hole applications in machine tools, CNC tapping heads, and hand-tapping operations using standard tap holders for this thread size.

Installation Notes

Installation should be performed by machinists or qualified tradespeople using a properly sized tap wrench, tapping head, or CNC rigid tapping setup. Ensure the workpiece is securely fixtured and the tap is aligned perpendicular to the hole before engagement. Apply appropriate cutting fluid for the workpiece material to reduce heat and extend tap life. Follow applicable shop safety procedures and machinery guarding requirements when using power tapping equipment.