How to Connect Black Iron Pipe Without Threads

Black iron pipe is used for gas lines in the home. The pipe is coated black so that it can easily be distinguished from other types of steel pipe. It comes in pre-cut lengths and is threaded at both ends. The pipes are connected together using couplings. Sometimes, if a gas pipe has been cut, the ends on each side of the cut won't be threaded. However, for the two pieces of pipe to be connected properly (and if used for a gas line they certainly need to be), the ends will need to be threaded prior to installation.

• 1

  Place one unthreaded pipe in a pipe vise, with the end roughly 12 inches from the vise jaws. Smear cutting oil around the pipe end with a brush. Place a die against the end of the pipe. Push and turn the die clockwise at the same time. Turn the die a half turn before turning it counterclockwise a quarter turn to help remove metal shavings from the die.

• 2

  Turn the die another clockwise half turn, then turn it counterclockwise another quarter turn. Repeat this process until the pipe end nearly sticks out of the other end of the die. Remove the die from the pipe by turning it counterclockwise, and clean the new thread with a rag. Repeat this whole process with the other unthreaded pipe end.

• 3

  Apply thread compound around both newly threaded pipe ends --- use a brush. Thread on a steel coupling to one of the pipe ends by hand. Place a pipe wrench around the coupling to tighten it in place. Thread the remaining pipe into the other end of the coupling by hand. Tighten the pipe in place using the wrench.