Osg 1296600 Spiral Flute Extension Tap 8-32 Unc H3

Product Description

The OSG 1296600 is a spiral flute extension tap designed for right-hand threading of 8-32 UNC threads in a 2B class of fit. Built from high-speed steel with a bright, uncoated finish, this tap features a 50-degree helix angle that promotes efficient chip evacuation up and out of the hole during the threading operation. The plug chamfer provides a gradual lead-in, making it well suited for through-hole tapping applications. Overall length is 4 inches, with a thread length of 3/4 inch (0.401 inch decimal), giving it the extended reach required for recessed or obstructed hole locations.

This extension tap is used in machining and fabrication environments where standard-length taps cannot reach the workpiece. Rated for use in aluminum, carbon steel, and cast iron, it fits into production and maintenance tapping operations across metalworking, tooling, and industrial repair shops. The reduced shank and 3/4-inch neck length allow clearance in confined areas. Installers and machinists working with tapping heads, hand tap wrenches, or CNC tapping cycles will find the spiral flute geometry effective for consistent thread formation in these common materials.

Key Features

• Spiral flute design with 50-degree helix angle for upward chip evacuation in through-hole applications
• 8-32 UNC thread size with H3 thread limit for consistent 2B class of fit tolerances
• Plug chamfer provides gradual thread lead-in for smooth starting
• 4-inch overall length with reduced shank and neck for extended reach in obstructed locations
• High-speed steel construction for durability across aluminum, carbon steel, and cast iron
• Bright, uncoated finish - no coating buildup to affect thread dimensions

Compatibility

Rated for threading aluminum, carbon steel, and cast iron. Designed as an OSG Series 918 extension tap for 8-32 UNC through-hole tapping applications requiring a plug chamfer and 2B class of fit.

Installation Notes

This tap is installed and operated by machinists or maintenance technicians using a hand tap wrench, tapping head, or CNC tapping cycle. Ensure the workpiece is securely clamped and the tap is aligned perpendicular to the hole before engagement. Apply appropriate cutting fluid for the workpiece material to extend tool life and improve thread quality. Reverse the tap periodically when hand tapping to break chips and prevent binding.