Osg 1240802 Spiral Point Tap 5/16-18 Unc Hss

Product Description

The OSG 1240802 is a spiral point tap designed for threading through-holes in a wide range of metallic workpieces. It carries a 5/16-18 UNC thread form with a plug chamfer and a 2-flute spiral point geometry that pushes chips forward ahead of the cutting zone, reducing clogging in through-hole applications. The tap is manufactured from high-speed steel and finished with an elektraLUBE coating, which provides built-in lubricity to extend tool life and reduce heat buildup during cutting. Thread fit is Class 2B with an H5 thread limit, producing a standard commercial thread tolerance. Thread length is 1.125 inches. The right-hand cutting direction suits standard CNC and manual tapping operations.

This tap is suited for threading through-holes in production machining, maintenance, and repair environments. It is specified for Series 105 and handles a broad material application range including aluminum, cast aluminum, cast iron, low-carbon steel, medium-carbon steel, high-carbon steel, and hardened steel. It is a practical choice for job shops and maintenance machinists who need a single tap capable of working across common ferrous and non-ferrous workpiece materials without changing tooling.

Key Features

• 5/16-18 UNC thread form with plug chamfer for standard through-hole tapping entry
• 2-flute spiral point geometry pushes chips forward, reducing chip packing in through-holes
• High-speed steel construction provides toughness across a wide material range
• elektraLUBE coating delivers integrated lubrication to reduce friction and extend tool life
• H5 thread limit and Class 2B fit meet standard commercial thread tolerance requirements
• Right-hand cutting direction; compatible with standard tapping heads, CNC rigid tapping, and manual tap wrenches

Compatibility

Designed for through-hole tapping in aluminum, cast aluminum, cast iron, low-carbon steel, medium-carbon steel, high-carbon steel, and hardened steel workpieces per the OSG Series 105 specification.

Installation Notes

Install in a standard tap holder, rigid tapping chuck, or manual tap wrench sized for the shank. Ensure the workpiece is securely fixtured and the pilot hole diameter is correct for a 5/16-18 UNC tap before starting. Apply cutting fluid if supplemental lubrication beyond the elektraLUBE coating is required for the specific material. Verify spindle direction and speed settings before engaging the tap in CNC applications to avoid thread damage or tool breakage.