Pipe Threader

A pipe threader (or threading machine) cuts uniform helical grooves into the outside of rigid steel or iron pipe, creating male threads that mate with female-threaded fittings like couplings, elbows, and tees. Manual threaders are hand-cranked and used for smaller jobs or field work; powered threaders run on electricity or air and are standard in shops for volume work. The tool holds a die head with multiple cutting dies that advance gradually as you turn the handle or engage power, and you must use cutting fluid—usually a heavy oil—to cool the dies and clear chips.

Threaders come sized for specific pipe diameters (typically 1/8" through 2"), and using the wrong die head will produce poor threads or damage the tool. In the field, you run the threader slowly and steadily; rushing creates chatter marks and weak threads that fail under pressure or vibration. Always secure the pipe in a vise before threading—loose pipe will spin out and cause injury.

Threaded connections are still common in older homes and in gas lines where codes permit, but modern plumbers use far fewer threaded joints than PEX or soldered copper. When you do thread, cut clean threads without nicks, backups, or rough edges—a bad thread will leak under pressure or cross-thread and strip the fitting.