Drill pipe lock (nipple and coupling) short version NKT-73

Designed for repair and technological needs during oil well workover, for assembly of technological columns. Threads of the nipple and coupling are made with hardening in the part that mates with each other and is constantly subjected to screwing and unscrewing during assembly and disassembly of the string, which increases the service life of threaded joints. The threads, which are used to connect to the pipes, are made without additional hardening and are not subject to disassembly during the entire service life.