Osg 1140700 Straight Flute Tap 5/16-18 Unc Plug Hss

Product Description

The OSG 1140700 is a straight flute tap designed for cutting internal threads in a variety of ferrous and non-ferrous metals. Built from high-speed steel with a bright, uncoated finish, it cuts a 5/16-18 UNC right-hand thread to a 2B class of fit with an H5 thread limit. The plug chamfer - typically 3 to 5 lead threads - makes it well suited for through-hole tapping where the tap can extend past the bottom of the hole. With 4 flutes and a 1-1/8 inch thread length, this tap removes chips efficiently during hand or machine tapping operations. Overall length is 2-23/32 inches. Machinists, tool-and-die technicians, and maintenance tradespeople reach for this tap when threading in tight tolerances is required.

This tap is intended for use in through-hole and open-hole tapping applications. Material compatibility includes aluminum, cast aluminum, cast iron, low-carbon steel, medium-carbon steel, and high-carbon steel. It is appropriate for use on drill presses, tapping machines, CNC machining centers, or manual hand-tapping setups. The 5/16-18 UNC thread size is a standard fastener thread widely used in structural and mechanical assemblies across industrial, HVAC, and mechanical contracting work.

Key Features

• 5/16-18 UNC right-hand thread, 2B class of fit with H5 thread limit for consistent tolerance control
• Plug chamfer style for through-hole tapping applications
• 4 straight flutes for chip evacuation in through-hole conditions
• High-speed steel construction provides durability across a broad range of workpiece materials
• Bright, uncoated finish - suitable for use with standard cutting fluids
• Compatible with aluminum, cast iron, low-, medium-, and high-carbon steel

Compatibility

Designed for tapping 5/16-18 UNC through-holes in aluminum, cast aluminum, cast iron, low-carbon steel, medium-carbon steel, and high-carbon steel workpieces. Part of OSG Series 101.

Installation Notes

Use the appropriate tap drill size for a 5/16-18 UNC thread before tapping. Apply a suitable cutting fluid or tapping compound for the workpiece material to reduce heat and extend tap life. Secure the workpiece fully before beginning the tapping operation. When using on a machine, ensure the tap is aligned perpendicular to the workpiece surface to avoid tap breakage or thread distortion.