Osg 0145308 Spiral Flute Sti Tap 8-32 Unc Hss

Product Description

The OSG 0145308 is a spiral flute STI tap designed for cutting Screw Thread Insert threads in a variety of materials. It features a 3-flute, 45-degree right-hand helix configuration and a bottoming chamfer, making it suitable for threading holes close to the bottom of a blind bore. The tap is manufactured from high-speed steel with a V finish and conforms to 8-32 UNC thread standards at a 2B class of fit. The H3 thread limit ensures consistent tolerance control across production runs. Licensed machinists and maintenance technicians working on precision assemblies will find this tap appropriate for insert-thread applications where standard tapped holes require reinforcement.

This tap is intended for use in applications requiring STI thread forms, typically in aerospace, automotive, and general industrial maintenance where Screw Thread Inserts are installed to repair or strengthen threaded holes. The 8-32 UNC specification places it in common use for smaller fastener assemblies. With an overall length of 2.375 inches and a 15/16-inch thread length, it is sized for use in standard hand tap handles or machine tapping fixtures. The bottoming chamfer allows threading to near the bottom of shallow blind holes where standard plug or taper chamfers cannot reach.

Key Features

• 8-32 UNC thread form at 2B class of fit for consistent STI thread production
• 45-degree right-hand helix promotes efficient chip evacuation in blind hole applications
• Bottoming chamfer allows threading close to the base of blind bores
• High-speed steel construction provides durability across a range of workpiece materials
• H3 thread limit supports controlled tolerance for insert-ready threads
• Series 302 designation identifies OSG standard STI tap product line

Compatibility

Designed as an OEM-style replacement spiral flute STI tap for standard 8-32 UNC insert-thread applications. No specific compatible model numbers or system families were identified in the available product data.

Installation Notes

This tap is installed by machinists or maintenance technicians using a standard tap handle or tapping machine set to the appropriate speed and feed for the workpiece material. Ensure the workpiece is securely fixtured and the tap is properly aligned to the pre-drilled STI hole before engagement. Apply cutting fluid appropriate to the material being tapped to extend tool life and improve thread quality. Inspect the tap for wear or chipping before each use and replace if thread form quality degrades.