How to thread a 3/4 pipe

How to thread 3 4?

thread, pipe

From the information given above, it can be stated that threading on a pipe is not a difficult process and is quite doable at home.

The main thing is to choose the right device and all the elements for it, while the process of how to cut a thread on a pipe will not take much time and you will succeed.

Pipe clamp is a device for cutting external threads on metal pipes, which subsequently allows them to be connected. Such a tool is popular among plumbers when installing heating and plumbing systems.

DEMO: How to Thread Steel Pipe

Left die and other specialized models

Professionals use in their work, in addition to the usual traditional dies, and special ones. They allow for more precise carving. They also come in different types: metric, left-handed, pipe, tapered pipe and others. A metric die is needed in cases where the thread must be metric (hence the name). All measurements will be in millimeters. There is also a special marking. “M”. You can often see the following values ​​on such dies. M 8, M 10.

Then it must be borne in mind that with these devices you can make threads with diameters equal to 8 and 10 mm. The carving takes place step by step, but each step is equal to the distance between the turns. It is necessary to pay attention to the fact that each die is distinguished by its main step in the thread. The step is not only the main one, but also the additional one. Example: a die of grade M 12, the main step is 1.75. In addition, you can find such markings as: M 12-1.5; M 12-1; M 12-0.75; M 12-0.5. The distance of each turn will be less if the step itself is less.

The left die can say everything about itself with one name. Such devices are necessary when a left hand thread is needed. These works are not so frequent, but, nevertheless, they do happen, therefore, special tools are needed for them. Let’s say you need to thread the joints, which then have to rotate. And if, in such a connection, you make a regular right-hand thread, then the result will be as follows. they will all immediately unwind back. You can find such dies by marking, they are marked like this. “LN”.

The pipe die is intended for the manufacture of cylindrical threads, and it can be not only small tubes, but also studs, rods and pipes, but only of large diameter. Usually all sizes are in inches and range from half to 2. It is only recommended to work with such a device if the pipes are made of non-solid metals. In addition, the walls should not have deformations. A tapered (inch) die is needed where a tapered thread should be obtained. Basically, they are used in factories, factories and industries where there are fuel pipelines, various machine tools. They have their own marking in the form of the letter “K”.

Description of construction

The teeth are located at such angles that turns are formed when the scraper rotates. The cutting edge of the tool has the shape of a cone, with a scraper thickness of 8-10 turns (teeth).

In most cases, manual pipe threading is carried out using a solid round rod.

The device for forming turns is fixed in a special holder, and its surface can have up to five grooves.

These grooves make up the working part, which consists of three zones. In the upper and lower parts there are conical sections. cutting zones, with the help of which the cutting is performed.

The device for making turns of a round shape can be used for cutting pipe, metric or inch threads.

Such tools have one advantageous feature. when forming, all three edges of the working section work, this allows you to create a thread on the pipe in one pass.

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External threading

Outside threads on bolts, rods and screws are manually cut with dies.

They are divided depending on the device:

  • prismatic;
  • round;
  • sliding;
  • whole.

The prismatic ones have a pair of identical halves, which are fastened in a die in the form of a frame with handles. On the two outer sides of these dies there are prismatic grooves designed for prismatic protrusions of the die.

The prismatic dies have a pair of identical halves, which are mounted in a die in the form of a frame with handles.

Sliding dies are installed in the die so that the numbers on its parts are opposite the same numbers on the frame. Otherwise it will turn out wrong. They are fastened with a stop screw. A steel plate is placed between the die and the stop screw so that it does not burst when pressed with the screw.

The round die is fixed in the easy-holder with a pair or two pairs of stop screws.

With the help of the sliding version, you can make a thread if there are slight deviations in the diameter of the rod, which cannot be allowed when cutting with round solid dies. With a smaller diameter of the rod, an incomplete thread will be obtained, with a larger diameter. even.

It will take

In this case, the Chinese version is presented, quite good.

There is such a thing in the region of 200-500 rubles. It all depends on the diameter and the margin. Running models for diameters 1/2, 3/4 inches and inch as in my version.

You can ask the plumbers for the Soviet counterpart, if there is such an opportunity. Then it will be generally free for you.

Threading dies. tool designs and shapes

The very first option we mentioned is a solid die, its use allows you to always achieve good quality threads. Both metric and inch dies can be solid. Achieving a good result is obtained due to the high rigidity of the material from which it is usually made, but the only drawback of such devices is low wear resistance. But cut models are used if high accuracy is not required. These devices may spring slightly during operation, and as a result, the thread being cut will change in diameter, and the difference is usually between 0.1 and 0.3 mm. The disadvantage is low rigidity, which affects the quality of work, a clean and accurate thread is not obtained.

To use the devices of the sliding type, you need to have a klupp when working. Thanks to special guides, it will be more convenient to work with sliding dies. Usually in such a model there are two main parts, which are tightly fixed in the frame of the die with a cracker and a special screw. It is the screw that helps to precisely adjust the created thread. To get started, you need to arm yourself with a whole die set, then you will be able to make threads of any size without coming up with any workarounds.

The form of these devices does not play a special role in the work. You can use round, square, hex options. The most important thing is to fix them firmly with the locking screws. Tapping chucks are often used for such purposes. To make this all possible, there are small conical grooves on the outer cylinders, as well as corner grooves. The grooves help in cases where the dies need to be cut with a grinding wheel. This work is carried out along the bridges and allows you to adjust the thread diameter well. If a round die is used, then collars are needed, on which there are five special screws. They also help to adjust the thread diameter well.

Thread cutter.

For fixing the dies, a die with a rectangular or oblique frame is used.Prismatic protrusions of the die enter the grooves of the dies, and from the side the dies are pressed with bolts.

To avoid direct pressure of the bolt on the dies, a so-called crackle is installed between the dies and the bolt (see Fig. 3, b), in the form of a dice.

The circumstances of the appearance of the defective thread

If the above requirements are not met, the thread may be defective, which will not allow properly and tightly connecting shut-off valves or fittings for sewer pipes.

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Much more often the circumstances of marriage are:

  • incorrectly selected tools. dies and pipe diameter, connection stroke or its type do not correspond to each other;
  • low-quality dies or klupp. if the cutting edge is damaged or dull, it will not be possible to make a high-quality connection;
  • insufficient lubrication;
  • use of dies without relevant experience in work.

Pipe threading tool.

On pipes, the thread is cut with a special die. Klupp for cutting pipes through the device differs from conventional die-blocks. Four steel combs enter the slots of its cage.

By turning the upper handle, they can be brought together or moved apart. Therefore, pipes of different diameters can be cut with one die. In addition, the klupp has guides that are adjustable with the lower handle.

Guides ensure the correct position of the die on the pipe when cutting.

When cutting, pipes are fixed with a special pipe clamp. The clamp consists of a frame, in which crackers are placed with cutouts for pipes of various diameters.


Before you can cut a thread on a pipe with your own hands, it is necessary to carry out a number of preparatory work:

How to Thread Pipe; A Beginner’s Tutorial

  • cut a piece of pipe to the desired size. If any section of the pipeline is being replaced, then it is required to carefully cut out the pipe that has become unusable;

The cut of the pipe must be perpendicular to its walls. Otherwise, the threaded connection will not be reliable.

  • the section of the pipe where the thread will be cut is cleaned of paint, rust, and so on. All foreign deposits interfere with the work;
  • a chamfer is removed from the end of the pipe to facilitate the work of the die.

Tools used for tapping

Before proceeding with the work, it is necessary to prepare a pipe threading tool, which includes the following accessories:

  • tape measure, pencil and caliper. The pipeline is assembled according to a previously prepared scheme. At the first stage, it is necessary to prepare pipes of a certain length, indicated in the diagram. A tape measure and a pencil are used for marking. A vernier caliper is used to measure the diameter of pipes and select the right tool;

Tape measure and caliper for measuring pipes

It is necessary to mark pipes very carefully and accurately. Any inaccuracy in measurement can lead to the assembly of the wrong design, leading to the need for re-fabrication of the pipeline.

  • angle grinder. The tool is used to cut pipes according to previously applied markings. Instead of an angle grinder, you can use a hacksaw for metal;

Tool for cutting metal pipes

  • vice. Pipe threading should be done clearly horizontally. For this, the pipe section must be securely fixed;

Device for fixing the pipe in a certain position

  • machine oil and any other lubricant. Cutting threads on pipes by hand will be much easier if the tool and the end of the pipe are lubricated with special agents;
  • glasses for eye protection. Any work must be done in compliance with all safety rules. When threading, metal shavings can get into the eyes and cause severe damage to them, therefore protection in the form of goggles is necessary;
  • pipe threading tool. This can be one of three options:

A set of dies for cutting threads of different sizes

Internal threading tools

Tool selection should be based on thread type and foreman priority. To apply external threads, dies are used, which are installed in a die or die holder. To apply internal threads, taps are used.

Die-cutting technology.

Cutting with prismatic dies is somewhat different from cutting with lers. When cutting with dies, the rods are not cut into a cone, but the dies are moved apart.

Then they are clamped on a rod, the end of which must coincide with the upper plane of the dies. By turning the screw to the right and slightly to the left, the thread is cut.

How to Thread Pipe EXTREMELY FAST

The position of the holder and the die is set strictly perpendicular to the rod to be cut, otherwise the thread will be oblique and one-sided.

I cut a thread on a pipe with a stick or a die.

For threading on a pipe with a diameter of 15 (aka 1/2 ″, aka half an inch), I usually use a lerk holder, which I put on the prepared pipe cut, with the side that has edges, due to its length, it acts as a guide, which is important for uniform engagement with a scraper. I lightly press down on the butt with my hand and rotate it over the edges with an adjustable wrench, clockwise. It is not always possible to use the guiding side, this is due to the fact that the pipe cut for some reason was made very close to the tie-in into the riser, then you make the entry from the side of the bench

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In this case, you need to be more careful, keep the stick perpendicular to the pipe axis, otherwise the thread may go crooked and the fourth coil will push the pipe through and through. Actually, if the chamfer is removed along the entire diameter evenly, then the entry will go exactly, respectively, and the entire thread

It is not always possible to use the guiding side, this is due to the fact that for some reason the pipe cut was made very close to the tie-in into the riser, then the entry is made from the side of the bench. In this case, you need to be more careful, keep the stick perpendicular to the pipe axis, otherwise the thread may go crooked and the fourth coil will push the pipe through and through. Actually, if the chamfer is removed along the entire diameter evenly, then the entry will go exactly, respectively, and the entire thread.

You can also cut a thread with a die, but usually a pipe of this diameter is used for routing, and it is not possible to use a knob due to its massiveness.

On a pipe with a diameter of 20 (aka 3/4 ″, aka three-quarters of an inch), I cut the threads with a die, although just in case I have a three-quarter cutter in the holder. For the same reasons as in the above paragraph.

And pipes with a diameter of 25 (aka 1 ″, aka inch) and a diameter of 32 (aka 1 1/4 ″. She is an inch and a quarter), I cut only with klups with a ratchet wrench. This is due solely to the complexity of this work. Using kluppa, the process is much simpler, easier and faster.

In the photo, in addition to the lerka and screw plugs with a knob, I presented what I use for the tightness of the threaded connection, namely, universal, plumbing sealant and plumbing flax. After I cut the thread, I put a sealant on it, trying to distribute it evenly over all the turns, and after that I wind the flax, I talk about this (and show) in detail in another article, I will leave the link below.

Connections are not only threaded.

In my profession, I have to combine polypropylene with cast iron when installing a sewage system. Basically, this connection is carried out by means of a transitional rubber cuff, which, by coating with sealant, is inserted into the socket of a cast-iron pipe or fitting, and already into it you insert a fitting or a polypropylene pipe coated with sealant. Due to this, the connection is tight.

The photo shows a bobbin, different in thickness, it is also used when installing the sewage system, by ramming it into the gap between the materials described above. The use of a bobbin is convenient because you can dissolve it and choose a strand of the required thickness. Its use is relevant in the case when the transitional cuff does not fit in size, such cases are not common, but still occur.

Perhaps these articles will be useful to you: How to thread a pipe. 10 important nuances How to wind up the thread tightly How easy it is to cut with an angle grinder

If you have any questions or additions, write in the Комментарии и мнения владельцев section. That’s it for today, success in your work, sincerely Andrey.

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