Which method is typically used to join iron pipes?

The method typically used to join iron pipes is threading. Threading involves cutting a helical groove into the end of the pipe, allowing it to be screwed into a matching threaded fitting or another pipe. This technique is widely used in plumbing and other applications where a strong, leak-proof connection is necessary for transporting liquids or gases.

Threaded joints provide a reliable way to connect pipes without the need for additional materials, such as adhesives or solder, and allow for easy disassembly if maintenance is required. In comparison, other methods such as soldering, crimping, and welding are more common in different contexts or for different types of materials. Soldering, for example, is primarily used with copper pipes, while crimping is generally used with flexible tubing in specific applications. Welding may be appropriate for certain metal pipes but is less common for smaller iron pipe installations due to the special equipment and skills required.