Osg 0138701 Spiral Flute Tap 1/2-13 Unc Bottoming 2B Vss

Product Description

The OSG 0138701 is a spiral flute tap designed for cutting internal 1/2-13 UNC threads in a bottoming configuration. It features a 45-degree helix angle that ejects chips upward out of the hole, making it well suited for blind-hole tapping operations. Constructed from vanadium high-speed steel and finished with a steam oxide coating, it provides improved lubricity and corrosion resistance during use. With a 2B class of fit and H5 thread limit, the tap produces threads within standard tolerance for general mechanical assemblies. The overall length is 3.375 inches with a shank diameter of 0.367 inches.

This tap is intended for use in ferrous materials including stainless steel, high-carbon steel, low-carbon steel, and medium-carbon steel. The bottoming chamfer allows threading to the bottom of a blind hole, which is a common requirement in close-tolerance mechanical work. It is appropriate for use in machine shop environments and by machinists, millwrights, and maintenance technicians working with 1/2-13 UNC fastener applications.

Key Features

• 45-degree right-hand spiral flute geometry for efficient upward chip ejection in blind holes
• Bottoming chamfer for threading to the base of blind holes
• Vanadium high-speed steel construction for toughness in ferrous materials
• Steam oxide coating improves lubricity and reduces galling
• H5 thread limit with 2B class of fit for standard tolerance internal threads
• No coolant-through design; suitable for use with cutting fluid applied externally

Compatibility

Designed for tapping 1/2-13 UNC internal threads in stainless steel, high-carbon steel, low-carbon steel, and medium-carbon steel workpieces. Compatible with standard 1/2-13 UNC bottoming tap applications in machine, maintenance, and production environments.

Installation Notes

This tap should be installed in a rigid tapping holder or CNC tapping chuck rated for the shank diameter. Ensure the workpiece is securely fixtured and the drill press or machining center is powered down before changing tooling. Apply a suitable cutting fluid or tapping compound appropriate for the workpiece material prior to use. Follow shop safety protocols and ANSI B94.9 standards for tap selection and application.