Osg 1296200 Spiral Flute Extension Tap 6-32 Unc H3

Product Description

The OSG 1296200 is a spiral flute extension tap designed for threading 6-32 UNC holes in a range of common metals. Built from high-speed steel with a bright, uncoated finish, this tap runs a 50-degree helix angle and a plug chamfer to ease thread starting. It carries an H3 thread limit and a 2B class of fit, making it suitable for standard unified thread tolerance requirements. With an overall length of 4 inches and a reduced shank design, it reaches into deeper or recessed features that standard-length taps cannot access. Machinists and tool-and-die professionals are the primary users of this tool.

This tap is suited for production and maintenance threading operations in aluminum, carbon steel, and cast iron. The spiral flute geometry evacuates chips upward, keeping the cutting zone clear during blind-hole threading. The extended 4-inch overall length makes it a practical choice when tooling must reach past fixtures, adapters, or deep-set bosses in a workpiece. Right-hand thread direction and right-hand flute direction follow standard convention for general-purpose tapping setups.

Key Features

• Spiral flute design with 50-degree helix angle for efficient chip evacuation in blind holes
• H3 thread limit with 2B class of fit for standard unified thread tolerances
• 4-inch overall length with reduced shank for extended reach applications
• Plug chamfer for controlled thread starting
• High-speed steel construction rated for aluminum, carbon steel, and cast iron
• Bright, uncoated finish suitable for use with standard cutting fluids

Compatibility

Designed for threading 6-32 UNC right-hand threads in aluminum, carbon steel, and cast iron workpieces. Fits standard tap holders and tapping heads accepting a 0.141-inch shank diameter with a 0.11-inch square drive.

Installation Notes

Tapping operations should be performed by a qualified machinist following shop safety procedures. Ensure the workpiece is secured and the tap is properly aligned with the drilled pilot hole before applying torque. Use an appropriate cutting fluid for the material being tapped to extend tool life and improve thread finish. Do not force a tap that has stopped turning freely, as high-speed steel is brittle and susceptible to breakage under excessive lateral load.