1. For tube casings and couplings 2. Multi-tooth thread, 8API Round ... oil and gas industry at home and abroad for many years. SMT carbide API threading inserts are ... buttress threads, 3,4,5,8,10 TPI available for cutting J55, L80, L80, and P110. Any ... forms with drawings and samples are also welcome. For more information, you are very welcome to contact ... -lock Multi-tooth Carbide API Inserts for couplings