Osg 8011200 Spiral Flute Sti Tap 1/4-20 Unc Hss

Product Description

The OSG 8011200 is a spiral flute STI (Screw Thread Insert) tap designed for cutting internal threads that accept helical wire thread inserts. Built from high-speed steel with a bright finish, this tap produces a 1/4-20 UNC thread in a variety of metals including aluminum, carbon steel, cast iron, and hardened steel. The 50-degree helix angle promotes efficient chip evacuation in blind and through holes. The bottoming chamfer allows threading close to the bottom of a blind hole, making this tap well suited for applications where full thread depth is required. It is a right-hand flute design and carries an H3 thread limit for consistent dimensional accuracy.

This tap is used in machining, maintenance, and repair operations where STI threaded inserts are required to restore or strengthen threads in production or field environments. It is commonly installed by machinists, maintenance technicians, and toolroom professionals working on aluminum housings, steel fabrications, and cast iron components. The 3-flute geometry handles a range of materials without specialized coatings, and the bright finish suits general-purpose applications where cutting fluid is applied during tapping.

Key Features

• STI thread form produces oversized internal threads designed to accept helical wire inserts
• 50-degree helix angle promotes chip evacuation in blind holes and interrupted cuts
• Bottoming chamfer allows threading to within one to two threads of the hole bottom
• High-speed steel construction handles aluminum, carbon steel, cast iron, and hardened steel
• H3 thread limit provides controlled tolerance for consistent insert fitment
• Right-hand flute direction for standard right-hand thread cutting

Compatibility

Designed for use with 1/4-20 UNC STI thread insert systems in aluminum, carbon steel, cast iron, and hardened steel workpieces. Suitable for use with standard tapping heads, drill presses, CNC machining centers, and hand tapping operations in Series S108 STI tooling applications.

Installation Notes

STI taps should be used with appropriate cutting fluid for the workpiece material to extend tool life and improve thread quality. Secure the workpiece and ensure the tap is aligned perpendicular to the hole before beginning. Use a calibrated torque wrench or tapping driver to avoid overloading the tool, particularly in hardened steel. Follow shop-specific tooling procedures and applicable safety standards when operating tapping equipment.