Osg 10801700 Spiral Flute Sti Tap 3/4-10 Unc Hss

Product Description

The OSG 10801700 is a high-speed steel spiral flute STI tap designed for cutting Screw Thread Insert (STI) tapped holes in a 3/4-10 UNC thread form. It features four right-hand flutes with a 50-degree helix angle, which promotes efficient chip evacuation in blind-hole applications. The bottoming chamfer allows threading to the bottom of a hole with minimal unthreaded depth remaining. A bright finish provides a clean, uncoated surface suited for general-purpose tapping operations. This tap is used by machinists, maintenance technicians, and tool-and-die professionals working with ferrous and non-ferrous materials requiring STI thread repair or new thread creation.

This tap is suited for through-hole and blind-hole threading operations where an STI insert is required to restore or establish a stronger thread in a parent material. The 3/4-10 UNC thread size is commonly encountered in heavy equipment, structural assemblies, and machinery maintenance. The Series S108 designation indicates it meets OSG standard tolerances for STI tapping. A 2B class of fit produces a standard tolerance threaded hole appropriate for general mechanical assembly. The 50-degree helix angle makes this tap particularly effective in softer materials and blind holes where chip flow upward out of the hole is essential.

Key Features

• 3/4-10 UNC thread form with STI profile for use with Screw Thread Insert installations
• 50-degree spiral helix angle drives chips upward for efficient blind-hole evacuation
• Bottoming chamfer allows threading to near full depth in blind holes
• 4-flute right-hand configuration provides stable cutting action and consistent thread form
• High-speed steel construction offers toughness and wear resistance across common workpiece materials
• Bright finish with H5 thread limit for standard STI tolerance requirements

Compatibility

Designed as a direct-fit STI tapping tool for 3/4-10 UNC applications requiring a 2B class of fit and H5 thread limit, consistent with standard Screw Thread Insert tooling requirements in the Series S108 product line.

Installation Notes

This tap should be installed and operated by qualified machinists or maintenance technicians familiar with STI tapping procedures. Ensure the workpiece is securely fixtured and the spindle or tap handle is properly aligned before beginning the cut to avoid tap breakage. Apply a cutting fluid appropriate for the workpiece material throughout the operation. Inspect the tap for wear or chipping before each use, as a damaged tap can produce out-of-tolerance threads or seize in the hole.