The STI (Screw Thread Insert) V-Tap Guides are for Helicoil type taps to repair striped out threads. STI V-TAP Guide (Unified Coarse Threads): Can handle standard ground STI hand tap sizes: 9/16-12, 1/2-13, 7/16-14, 3/8-16, 5/16-18, 1/4-20, 12-24, 10-24, 8-32, 6-32. STI V-TAP Guide (Unified Fine Threads): Can handle standard ground STI hand tap sizes: 5/8-18, 9/16-18, 1/2-20, 7/16-20, 3/8-24, 5/16-24, 1/4-28, 10-32, 8-36. |