Osg 1180700 Straight Flute Tap 5/16-18 Unc Hss

Product Description

The OSG 1180700 is a straight flute tap designed for cutting 5/16-18 UNC internal threads in a wide range of ferrous and non-ferrous materials. Built from high-speed steel with a bright, uncoated finish, this tap features a plug chamfer with 3 flutes and a right-hand thread direction. It carries an H5 thread limit and a 2B class of fit, making it suitable for standard tolerance threading applications. With an overall length of 2-23/32 inches and a thread length of 1-1/8 inches, it fits standard tap holders and hand-tapping setups used by machinists, pipefitters, and maintenance trades.

This tap is intended for through-hole and blind-hole tapping operations where chip evacuation is managed manually or with cutting fluid. The plug chamfer provides a balance between ease of starting and thread engagement depth, making it a general-purpose choice for production and repair work. It is rated for use in aluminum, cast aluminum, cast iron, high-carbon steel, low-carbon steel, and medium-carbon steel. The straight flute design suits materials that produce short, brittle chips rather than long stringy ones.

Key Features

• 5/16-18 UNC thread form with right-hand thread direction
• Plug chamfer for general-purpose through-hole and blind-hole tapping
• 3 straight flutes suitable for short-chipping materials including cast iron and aluminum
• H5 thread limit and 2B class of fit for standard tolerance requirements
• High-speed steel construction without coating for versatile material compatibility
• Coolant-through design not required - suited for hand or machine tapping with applied cutting fluid

Compatibility

Designed for use in aluminum, cast aluminum, cast iron, high-carbon steel, low-carbon steel, and medium-carbon steel. Compatible with standard 5/16-18 UNC tapping applications using conventional tap holders.

Installation Notes

This tap should be installed in a properly sized tap wrench or machine tap holder before use. Always secure the workpiece and ensure the tap is aligned perpendicular to the drilled hole before beginning the thread-cutting operation. Apply an appropriate cutting fluid for the material being tapped to reduce heat buildup and extend tool life. Reverse the tap periodically to break chips and prevent binding, especially in deeper blind holes.