Osg 1170802 Straight Flute Tap 5/16-18 Unc Bottoming Hss

Product Description

The OSG 1170802 is a straight flute bottoming tap designed for threading operations in a wide range of ferrous and non-ferrous materials. Built from high-speed steel, this tap cuts a 5/16-18 UNC right-hand thread with a 3B class of fit and an H3 thread limit. It features 3 flutes and a bottoming chamfer, making it suited for threading holes where maximum thread depth is required close to the bottom of a blind bore. Overall length is 2-23/32 inches with a thread length of 1-1/8 inches. No coolant-through capability is present. Machinists and maintenance technicians will find this tap ready for production and repair work across a broad range of shop materials.

The OSG 1170802 is intended for tapping operations in aluminum, cast aluminum, cast iron, high-carbon steel, low-carbon steel, and medium-carbon steel. Its bottoming chamfer makes it the correct choice when threading must extend to the base of a blind hole after a taper or plug tap has already started the thread. This tap fits standard manual tap handles and machine tap holders used in drill press, CNC, and hand-tapping applications.

Key Features

• Bottoming chamfer for threading close to the bottom of blind holes
• 5/16-18 UNC thread form with right-hand direction and 3B class of fit
• H3 thread limit for consistent dimensional tolerance across production runs
• High-speed steel construction for durability across ferrous and non-ferrous materials
• 3-flute geometry for chip clearance and stable cutting action
• No coolant-through design suits standard manual and light machine tapping setups

Compatibility

Designed as an OEM-style replacement or standard-production straight flute bottoming tap compatible with 5/16-18 UNC threaded applications in aluminum, cast aluminum, cast iron, high-carbon steel, low-carbon steel, and medium-carbon steel workpieces.

Installation Notes

This tap is installed and operated by qualified machinists or maintenance technicians familiar with threading operations. Always secure the workpiece and use a properly sized tap wrench or machine holder before beginning. Apply appropriate cutting fluid for the workpiece material to extend tool life and improve thread quality. When threading blind holes, use a taper or plug tap first to establish the thread before using this bottoming tap to complete depth.