Introduction
Threading galvanized or black steel pipe is a necessary step to connect existing or new pipe together. Threading can be done by hand or machine but the correct tool is necessary for the job.
Thread Type
Steel or iron pipe is typically cut to the National Pipe Thread standard or NPT. The threading has a slight taper which allows the pipe to create a tight seal in fittings. You can find other types of metal pipe such as brass or plastic that have the same threading and it is commonly referred to as “Iron Pipe” thread due to its common use with steel pipes. There are other thread types that are also used with steel pipe but NPT is the most common in North America.
Tools Required
Before starting to thread steel pipe, it’s best to have the required tools and safety equipment prior to starting. For safety equipment, always wear eye protection while threading pipe. Sharp metal shavings can fly off and land in your eye. Gloves can be used when using a ratchet threader but not when using a pipe threading machine as the gloves can get caught in the rotating pipe.
Tools such as pipe clamps or pipe stands are necessary to secure the pipe when using a threader. If using a threading machine, the machine might serve as both the clamp and stand. Other tools such as pipe cutters and reamers are necessary to cut and clean the pipe prior to threading.
Ratchet Threader
A ratchet threader such as the RIGID threader works by installing dies into the threader body and ratcheting to cut the pipe. Here is a video that demonstrates how to use a ratchet threader.
Machine Threader
A machine threader such as the Milwaukee threader works by securing and rotating the die across the pipe. Other machines such as the RIGID pipe threader rotate the pipe and the die is wheeled by the operator on to the pipe. Here is a video that demonstrates the Milwaukee threader machine:
Which Tool Should I Choose?
For most DIYers, renting a threading tool is the most economical option. If you plan to have a tool in the toolbox, we’d recommend purchasing a ratchet threader as they are the least expensive option for small projects. If you are threading pipe for major project or professionally, a powered pipe threader is the best investment.