Osg 1120700 Straight Flute Tap 5/16-18 Unc Hss Plug

Product Description

The OSG 1120700 is a straight flute tap designed for cutting internal threads in a wide range of ferrous and non-ferrous materials. Built from high-speed steel with a bright uncoated finish, this tap produces 5/16-18 UNC right-hand threads to a 3B class of fit with an H3 thread limit. It features four flutes and a plug chamfer, which provides a gradual lead-in that works well in through-hole applications. Overall length is 2-23/32 inches with a thread length of 1-1/8 inches. This is a Series 101 tap from OSG, a precision cutting tool manufacturer. Machinists, toolroom technicians, and maintenance mechanics use this tap in hand or machine tapping operations.

This tap is suited for through-hole tapping in aluminum, cast aluminum, cast iron, low-carbon steel, medium-carbon steel, and high-carbon steel. The plug chamfer style makes it a versatile choice for general-purpose production tapping and repair work across light manufacturing, maintenance, and fabrication environments. The 5/16-18 UNC thread form is a standard unified coarse thread widely used in structural fastening and equipment assembly applications.

Key Features

• 5/16-18 UNC thread form with right-hand thread direction
• Plug chamfer for gradual thread engagement in through-hole applications
• 4 flutes for efficient chip formation in a broad range of materials
• H3 thread limit and 3B class of fit for standard tolerance threading
• High-speed steel construction provides durability across ferrous and non-ferrous workpieces
• Bright uncoated finish suitable for use with cutting fluids across many material types

Compatibility

Designed for tapping 5/16-18 UNC threads in aluminum, cast aluminum, cast iron, low-carbon steel, medium-carbon steel, and high-carbon steel workpieces. Compatible with standard hand tap wrenches and machine tap holders sized for a 0.318-inch shank diameter.

Installation Notes

This tap should be installed and used by machinists or maintenance technicians familiar with tapping operations and cutting tool handling. Secure the workpiece fully before beginning any tapping operation and use an appropriate cutting fluid for the material being tapped. When machine tapping, ensure the tap holder is aligned axially with the drilled hole to prevent tap breakage. Inspect the tap for wear or chipping before each use and replace when thread quality degrades.