Osg 2830801 Spiral Point Tap 5/16-18 Unc Plug H3

Product Description

The OSG 2830801 is a spiral point plug tap designed for cutting internal threads in through-hole applications. Built from vanadium high-speed steel (HSS-E) with a steam oxide coating, it produces 5/16-18 UNC threads to a 3B class of fit with an H3 thread limit. The plug chamfer provides a gradual lead-in for production tapping in CNC machining centers, drill presses, and manual tapping operations. The spiral point geometry pushes chips forward ahead of the cutting teeth, making it suited for through-hole work at consistent feed rates. Right-hand thread direction. Installed by machinists and tool-and-die professionals.

The OSG 2830801 is part of the OSG Series 280 tap line. It is rated for use in a wide range of materials including aluminum, low-carbon steel, medium-carbon steel, high-carbon steel, alloy steel, die steel, cast iron, stainless steel, and hardened steel. It does not require coolant-through capability and does not cut interrupted threads. Typical applications include production threading in manufacturing, fabrication shops, and maintenance repair operations where a standard through-hole UNC tap is required.

Key Features

• 5/16-18 UNC thread form, H3 thread limit, 3B class of fit for controlled thread tolerance
• Vanadium high-speed steel (HSS-E) construction for improved wear and heat resistance over standard HSS
• Steam oxide coating reduces friction and provides moderate lubrication retention
• Spiral point geometry pushes chips forward — optimized for through-hole tapping
• 3 flutes, plug chamfer for gradual thread engagement and consistent lead-in
• Right-hand cut, no coolant-through, non-interrupted thread — standard production tap configuration

Compatibility

Designed for cutting 5/16-18 UNC through-hole threads in aluminum, low-carbon steel, medium-carbon steel, high-carbon steel, alloy steel, die steel, cast iron, stainless steel, and hardened steel workpieces. OSG Series 280.

Installation Notes

Power down or lock out any tapping machine before loading or changing tooling. Use appropriate tapping fluid or cutting oil for the workpiece material to extend tool life and improve thread finish. Secure the tap in a proper tap holder or floating chuck to prevent misalignment and tap breakage. Follow shop-standard speeds and feeds for the material being tapped — excessive feed rate is a primary cause of tap breakage with plug-style taps.