Osg 0145201 Spiral Flute Sti Tap 8-32 Unc Vanadium Hss

Product Description

The OSG 0145201 is a spiral flute STI (Screw Thread Insert) tap designed for cutting internal threads that accept Heli-Coil-style inserts in metal workpieces. Manufactured from vanadium high-speed steel with a steam oxide finish, this tap handles demanding threading applications in carbon steel, hardened steel, and stainless steel. The 45-degree helix angle drives chips up and out of the hole, making it well-suited for through-hole and blind-hole work. The bottoming chamfer allows threading close to the base of a blind hole. Overall length is 2.125 inches, shank diameter is 0.168 inches, and thread length is 0.75 inches (0.311 inches in decimal). This is a 3-flute, right-hand-flute design with an H2 thread limit.

This tap is used in machine shop, manufacturing, and maintenance environments where stripped or damaged threads require insert repair, or where STI threads are specified in the original design. It cuts 8-32 UNC threads to accept the corresponding STI insert size. Typical applications include aerospace, automotive, and general metalworking operations on carbon steel, stainless steel, and hardened steel components. It is run in a tapping machine, CNC machining center, or drill press with appropriate tapping fluid for the workpiece material.

Key Features

• 8-32 UNC thread form sized for STI thread inserts
• 45-degree helix angle evacuates chips efficiently during tapping
• Bottoming chamfer threads close to the floor of blind holes
• Vanadium high-speed steel construction for wear resistance in ferrous materials
• Steam oxide finish reduces friction and provides light corrosion resistance
• H2 thread limit for controlled thread fit
• Right-hand flute, 3-flute design compatible with standard tapping holders

Compatibility

Designed for use in carbon steel, hardened steel, and stainless steel workpieces requiring 8-32 UNC STI threads. Verify STI insert series and tap holder shank requirements before installation.

Installation Notes

This tap should be installed by a machinist or qualified metalworker familiar with STI threading procedures. Secure the workpiece firmly and ensure the tap is held perpendicular to the work surface to avoid thread misalignment or tap breakage. Always apply an appropriate cutting fluid for the workpiece material, especially when tapping stainless or hardened steel. Power down all equipment and clear the work area before changing or inspecting taps.