Osg 1231700 Spiral Point Tap 3/8-16 Unc Bottoming Hss

Product Description

The OSG 1231700 is a spiral point tap designed for cutting 3/8-16 UNC internal threads in through-hole and production tapping applications. Built from high-speed steel with a bright finish, it features a bottoming chamfer and H3 thread limit, making it well-suited for applications that require threads close to the bottom of a blind hole. The 3-flute spiral point geometry pushes chips forward ahead of the cutting edge, reducing clogging in through-hole operations. Overall length is 2.938 inches with a thread length of 0.787 inches. This tap is installed by machinists, maintenance technicians, and tool-and-die professionals working with manual or CNC tapping equipment.

The OSG 1231700 is rated for use across a broad range of ferrous and non-ferrous workpiece materials including aluminum, cast aluminum, cast iron, low-carbon steel, medium-carbon steel, high-carbon steel, and hardened steel. Its right-hand thread direction and 3B class of fit make it a standard choice for general-purpose UNC fastener thread production in job shop, maintenance, and production environments. The bottoming chamfer style allows thread engagement very close to the floor of a blind hole, a common requirement in fixture and component assembly work.

Key Features

• 3/8-16 UNC thread size with 3B class of fit for standard fastener tolerance
• Bottoming chamfer for threading close to the base of blind holes
• H3 thread limit for controlled tolerance in medium-fit applications
• High-speed steel construction suitable for a wide range of workpiece materials
• Bright finish with no coating for straightforward re-sharpening
• Spiral point geometry pushes chips forward, reducing chip pack in through-hole tapping

Compatibility

Designed as a standard replacement spiral point tap for 3/8-16 UNC tapping operations across aluminum, cast iron, carbon steel, and hardened steel workpieces in manual, turret, and CNC tapping setups.

Installation Notes

Install in a tap wrench, tapping head, or CNC rigid tapping holder sized for the shank diameter before use. Power down or de-energize any CNC machine and confirm the spindle is fully stopped before changing tooling. Use appropriate cutting fluid for the workpiece material to extend tap life and improve thread finish. Inspect the tap for chipping or wear before each use, as a damaged tap can seize in the workpiece.