Osg 1122801 Straight Flute Tap 1/2-20 Unf Hss Oxide

Product Description

The OSG 1122801 is a straight flute tap designed to cut 1/2-20 UNF internal threads in a wide range of ferrous and non-ferrous materials. It features a plug chamfer, 4 flutes, and a right-hand thread direction. Built from high-speed steel with an oxide coating, this tap is suited for hand tapping and machine tapping operations where chip evacuation runs back through the flutes. Overall length is 3-3/8 inches with a thread length of 1-21/32 inches. The H3 thread limit and 3B class of fit make it appropriate for standard tolerance threading applications across production and maintenance environments.

This tap is used in metalworking applications across manufacturing, maintenance, and repair settings. It is rated for use in aluminum, cast aluminum, cast iron, high-carbon steel, low-carbon steel, and medium-carbon steel. The plug chamfer - typically 3 to 5 lead threads - makes it suitable for threading through-holes or starting a thread in a blind hole after a bottoming or taper tap has been used. It is appropriate for both manual and machine-assisted tapping operations in job shop and production environments.

Key Features

• 1/2-20 UNF thread form, right-hand direction, 3B class of fit
• H3 thread limit for standard tolerance threading
• 4 straight flutes for balanced cutting action in through and blind holes
• Plug chamfer for easy thread starting and versatile hole type compatibility
• High-speed steel construction with oxide coating for wear resistance and lubricity
• Rated for aluminum, cast iron, and low- to high-carbon steel applications

Compatibility

Designed for use in materials including aluminum, cast aluminum, cast iron, high-carbon steel, low-carbon steel, and medium-carbon steel. Compatible with standard 1/2-20 UNF tapping operations requiring a 3B class of fit and H3 thread limit.

Installation Notes

Installation is performed by machinists and maintenance technicians using a tap wrench, tapping head, or machine spindle. Always use appropriate tapping fluid for the workpiece material and ensure the tap is aligned perpendicular to the workpiece surface before applying torque. Back the tap off periodically to break chips and prevent tap breakage. Power down all equipment and secure the workpiece before beginning any tapping operation.