22. Basic Profile of Threads Intro Thick Steel Conduit Threads (CTG) SP Internal Threads SL External Threads PO Threads per inch ST Steel Conduit Threads (CTC) Internal Threads ROLL External Threads CARBIDE Threads per inch LONG Bicycle Threads (BC) HAND TAPS Internal Threads EG (STI) External Threads SPECIAL THREADS, GAUGES Threads per inch THREAD Tire Valve Threads (TV), Bicycle Tire Valve Threads (CTV) MILLS Internal Threads DIES External Threads CENTER DRILLS Technical Threads per inch info 712