Threading Inserts

STI Thread Taps

STI (Screw Thread Insert) taps are precision cutting tools designed with an oversized pitch diameter to accommodate helical wire inserts while maintaining standard nominal internal thread dimensions. Manufactured from high-speed cobalt steel and often utilizing low-friction PVD coatings, they manage high cutting forces during the oversize threading process. Available in various geometries such as spiral flute or spiral point, they ensure specific tolerance classes (e.g., 2B or 3B) are met. They are mandatory preparatory tools for thread reinforcement and repair operations in soft alloys and cast metals.