Osg 1010802 Straight Flute Tap 1-72 Unf Bottoming Hss

Product Description

The OSG 1010802 is a straight flute tap designed to cut internal threads in pre-drilled holes. Sized for 1-72 UNF threads and ground to an H2 thread limit, this bottoming tap features a short chamfer length that allows threading close to the bottom of a blind hole. With two flutes and a right-hand thread form conforming to 2B class of fit, it is manufactured from high-speed steel for consistent performance across a range of ferrous and non-ferrous materials. Overall length is 1.6875 inches with a thread length of 0.375 inches. Machinists and maintenance technicians use it in manual tap handles, T-handles, or machine tapping setups.

This tap is suited for production and maintenance applications where fine unified threads in the number 1 screw size are required. Typical uses include tapping holes in small mechanical assemblies, instrument enclosures, electronics hardware, and precision fixtures. The bottoming chamfer makes it the correct choice for blind holes where thread engagement must reach near the bottom of the bore. Compatible materials include aluminum, cast aluminum, cast iron, low-carbon steel, medium-carbon steel, and high-carbon steel, covering the most common workpiece materials encountered in general machining and maintenance work.

Key Features

• Bottoming chamfer for threading close to the bottom of blind holes
• 1-72 UNF thread form ground to 2B class of fit for standard tolerance assemblies
• H2 thread limit for controlled fit in typical production applications
• Two-flute straight design for chip management in through and shallow blind holes
• High-speed steel construction for use across aluminum, cast iron, and carbon steel
• Right-hand thread direction, compatible with standard tap handles and tapping machines

Compatibility

Designed for use in aluminum, cast aluminum, cast iron, low-carbon steel, medium-carbon steel, and high-carbon steel workpieces requiring 1-72 UNF internal threads to a 2B class of fit.

Installation Notes

Machinists and maintenance technicians install this tap using a standard tap handle, T-handle wrench, or machine tapping setup. The workpiece should be securely fixtured and the tap properly aligned with the drilled hole before threading begins to avoid tap breakage in small-diameter applications. Use an appropriate cutting fluid for the workpiece material to extend tool life and improve thread finish. For bottoming operations in blind holes, a spiral-point or plug tap should be used first to start the thread before switching to this bottoming tap.