A pipe threader is used to create external threaded pipes and the die head contains a set of dies that are used to create the threads on the pipe. The number of dies will depend on the size of the pipe being threaded. The size of the pipe thread is based on the outside diameter of the pipe and not the inside diameter. The inside diameter of the pipe is commonly referred to as flow size. Here is an example of how that measurement is presented
In this example the outside diameter of the pipe will be 1/4" and there are 12 threads on the pipe. The pipe form is NPT which stands for American Standard Pipe Taper Thread. There are many forms of pipe thread and here is a list of the most commonly used pipe thread forms.
How does it work?
The threading machine works by using carbide tip pipe dies that are held in by a die head. They typically pulls 4-6 feet of pipe through 5-10 feet of threaded pipe at one time, depending on the size being used. Pipe are typically designed to handle standard sized couplings that can have various thicknesses or diameter sizes. It is also possible for a worker to use two machines hooked together for pipe threading. This is done by using two machines that are opposite one another, pulling the piping through a longer section of larger pipe.
To begin, fill the machine with the appropriate threading oil. Cut the pipe to the desired length using a circular saw that can cut pipe and then ream the inside of the pipe using a pipe reamer. Select the right die size and change the the die in the machine's carriage. For safety purposes always wear cut proof gloves when handling pipes and cutting equipment. Insert the pipe onto the threader and secure it. Begin threading the pipe and once it is complete, untighten the clamp that secures the pipe and remove the pipe from the machine. It is important to properly maintain the machine after threading so ensure that the oil is cleaned and any metal chips are removed prior to storing.
Steps on How to Thread the Pipe:
1. ✅ Put pieces of pipe into the proper order with a coupling in between each piece.
2. ✅ Insert threader fully through first piece of pipe by pulling it out on the other side while rotating the adjustable handle clockwise so that it draws up on itself.
3. ✅ Put threads on both sides of pieces being joined or at least on the "cold" side of each piece as if it were a standard threaded connection.
4. ✅ Carefully pull back on the pipe being joined so that the threads sink into the material completely and form a solid seal. Most threaders have a depth gauge that allows you to judge how far in they've gone without pulling them out.
5. ✅ Push the threader forward, rotating the handle anti-clockwise and release it from the pipe.
6. ✅ The threader can then be removed and threaded material inserted into next section of pipe. Continue until all pieces to be combined have been joined.
How does a manual threader work?
A manual threader works by first cutting the end of the pipe with a pipe cutter. Place your pipe on a pipe vise or stand for holding pipe and use the pipe cutter to get a clean cut. Now using a pipe reamer, ream the end to remove any burrs that were created when the pipe was cut. The next step is to find which size die works for the pipe you are threading and once you determine the appropriate size put the die head onto the ratchet. Place the pipe guide over the pipe and begin applying pressure to the die head by moving the handle in a downward force with pressure from the top. The threading has now commenced and you can continue threading using a high quality threading oil. Rotating in the opposite direction will remove the die from the pipe and your external thread should be complete.
How to remove broken threaded pipe
If you have broken threaded pipe removing it can be difficult. To properly remove this type of pipe, you will need a new length of threaded pipe and a pipe extractor. Pipe extractors are used to remove broken pieces of threaded or PVC piping by drilling into the broken piece and pulling out the old pipe from inside it.
How to connect two threaded pipes:
1. ✅Measure and mark a spot on the outside of one section of threaded pipe that's about an inch away from where you want to place your new connection.
2. ✅Apply a liberal amount of PVC primer to this area on the inside of the pipe as well as to both sides of the new fitting, near its opening.
3. ✅Carefully insert the threaded end of the new pipe into the existing line, pushing it through until it reaches your mark.
4. ✅Tighten nut onto male side of pipe with adjustable wrench, creating a tight seal with the female threading on the other side.
Common Types of Pipe Thread Forms:
a. NPT: American Standard Pipe Taper
b. NPSC: American Standard Straight Coupling Pipe
c. NPTR: American Standard Taper Railing Pipe
d. BSPT: British Standard Pipe Thread Tapered
e. NPSM: American Standard Straight Mechanical Pipe
f. NPSL: American Standard Straight Locknut Pipe
g. NPTF: American Standard Pipe Tapered (Dryseal)
h. BSPP: British Standard Pipe Parallel
What are Tapered Threads:
Tapered threads are very important to secure pipe connections. The thread of the pipe is tapered rather than consistent at each level of the thread for the male fitting to rotate and secure into the female end. The male thread form inserts into the female tapered thread and as the male is rotated into the female to create a hydraulic seal. To secure it even further and prevent any leaks, pipe sealant is also used. Knowing the number of threads inside helps the user know how many turns it will take to complete the connection.