Osg 1590800 Spiral Point Tap 5/16-18 Unc Plug Hss

Product Description

The OSG 1590800 is a spiral point tap designed to cut 5/16-18 UNC threads in through-hole applications. Made from high-speed steel with a bright finish, this 2-flute plug chamfer tap pushes chips ahead of the cutting edge and out of the hole, making it well suited for production tapping on CNC machines and manual drill presses. The overall length is 2.719 inches with a thread length of 0.724 inches and a shank diameter of 0.318 inches. The H11 thread limit accommodates oversize tolerance requirements, with an oversize value of 0.0050 inches. The part weighs 0.052 pounds. Licensed machinists, tool-and-die makers, and CNC operators are the typical end users.

This tap is intended for through-hole tapping across a broad range of metals in both job shop and production environments. The material application list includes aluminum, cast aluminum, cast iron, low-carbon steel, medium-carbon steel, high-carbon steel, and hardened steel. The plug chamfer geometry provides a gradual thread lead-in, making it a reliable general-purpose choice when hole depth is not a limiting factor. It is part of the OSG Series 105H product line.

Key Features

• Spiral point geometry pushes chips forward and out of the hole during through-hole tapping
• High-speed steel construction provides durability across ferrous and non-ferrous materials
• H11 thread limit with 0.0050 inches oversize accommodates standard tolerance class fits
• Plug chamfer provides gradual thread lead-in for stable entry
• Right-hand thread direction, 5/16-18 UNC
• Bright finish, no coating — suitable for use with cutting fluid in most tapping applications

Compatibility

Designed for through-hole tapping of 5/16-18 UNC threads in aluminum, cast aluminum, cast iron, low-carbon steel, medium-carbon steel, high-carbon steel, and hardened steel. Coolant-through feature is not present on this tap.

Installation Notes

This tap should be installed in a tapping chuck or rigid holder with proper alignment to the drilled hole to prevent tap breakage. Power down or de-energize the machine before changing tooling. Use an appropriate cutting fluid for the material being tapped; dry tapping is not recommended for steel. Follow shop safety procedures and applicable OSHA guidelines when operating tapping equipment.