OSG Screw Thread Insert STI Tap: Spiral Fute, 7/16"-20 UNF, H3 / 2B-3B, 3 Flute

An OSG spiral-flute STI tap is used to cut internal threads in a workpiece before installing a screw thread insert. It is designed for bottoming chamfer applications, producing threads to H3 / 2B-3B tolerance. Common in aerospace, automotive, and general manufacturing where strong, replaceable threads are needed.

The OSG 8017400 is a spiral-flute STI tap with a 7/16"-20 UNF thread size, H3 / 2B-3B tolerance, 3 flutes, and a bottoming chamfer. It is designed for threading holes that will accept screw thread inserts. The spiral flute design aids chip evacuation in blind-hole applications.

You can source OSG STI taps worldwide through 3G Electric, a global industrial equipment distributor. We handle full logistics, customs clearance, and delivery to your facility. Contact us for availability and lead time on the OSG 8017400 or other OSG threading tools.

To select the correct STI tap, match the tap's thread designation to the insert's thread size. For a 7/16"-20 UNF insert, use an STI tap with the same 7/16"-20 UNF marking. The tap's H3 / 2B-3B tolerance ensures the tapped hole meets the insert manufacturer's requirements. Always verify the chamfer type (bottoming vs. plug) for your application.