Iron roughnecks are tools used in the drilling industry to connect and disconnect sections of drill pipe. These machines assemble drilling pipes by clamping the lower pipe in place while a rotary wrench fastens the top pipe. The pipes mate by a series of mating threads. To replace a drill bit or upon completion of the well, the pipe is backed out of the well and the roughneck's job is completed in reverse. What was once a dangerous and dirty job for manual laborers has been replaced by this machine which is typically automated or remotely controlled.
Video credit: Euzy2007