How to cut external threads on a pipe - Metals and their processing

How to cut external threads on a pipe?

When a pipeline is being repaired, it becomes necessary to insert it into the existing pipeline. If metal pipes are laid, you can use welding. To connect shut-off valves, you must have a special tool for cutting threads on pipes. Moreover, its production with such a device can be easily done at home with your own hands.

In most cases, a threaded connection remains the main type of joining of metal pipes. It has several parameters that are taken into account when installing the fittings. Correctly selected dimensions allow you to create a reliable and tight connection.

To work with a thread cutter, it is necessary to distinguish between types of thread, its parameters and characteristics.

Inch and metric cutting

Several parameters are considered to be a characteristic difference:

The part measurement is expressed in inches.
The thread profile resembles an isosceles triangle, the apex of which is 55 degrees.
Features a large step.
Large profile.
High strength.

In Russia, all measurements are performed in the metric system. Threading a threaded connection was no exception . The characteristic differences are:

Dimensions are indicated in millimeters.
The profile resembles an equilateral triangle.
A small step.

To connect water pipes, the inch system is used, the manufacture of fasteners is done in the metric system. If the reinforcement is screwed in a clockwise direction, the connection is called right-handed. If on the contrary, the thread is considered left-handed.

Types of tools

For the manufacture of threaded connections, the industry produces special cutting devices. They are designed to perform certain technological operations. A screw-like tool for creating internal threads is called a tap.

The device cuts chip grooves on the body of the pipe. For fastening in the driver, the tap has a long shank. The tool is produced in accordance with the current standard.

There are special tables that indicate the size of the tap, its number and type.

The cutting kit includes two taps. Their main difference is the depth of groove cutting:

Chernova - No. 1.
Finishing - No. 2.

Die device

This device is sometimes called a lerka. The tool is equipped with a kind of nut with several holes. It is this that creates the cutting edges.

The industry produces lerks of various shapes:

Klupp.
Round.
Split.
Sliding.
Whole.

Description of the clamp

It differs from other devices in its special guide, which centers the die relative to the pipe. The device can be electric or manual. For use at home, when cutting will occur no more than two or three times, it would be more rational to work with a manual clamp. Its cost is much less than an electric tool.

This tool is very convenient to work with. The thread is very clean and reliable. The light weight of the device and the simplicity of the design allow you to quickly replace the cutters.

The most important characteristic of a clamp is the material from which it is made. Expensive tool steel is used to create the die. But carving is created only by incisors. They must be highly durable.

The clamp does not have expensive non-functional elements. Therefore, a set of dies costs much less. The cost of threading a stainless steel pipe is dramatically reduced. Home craftsmen, not wanting to incur large financial losses, prefer to work with such a tool.

Self-cutting

There are several tools you can use to do the job:

Which tool set to choose depends on several factors. This is especially true for the type of carving. After all, it can be internal or external. After selecting a die, there are several steps to follow.

The old thread is cut off. Don't try to restore it. It will still remain leaky and leakage will occur. The cut should be strictly perpendicular to the longitudinal axis of the pipeline.
If there are traces of corrosion on the pipe, the segment must be completely removed.
To make it easier to screw the die onto the pipe, its end must have a lead-in chamfer.
For easier screwing, the location of the future thread is lubricated with oil.
After cutting several turns, the die needs to be scrolled back. Performing sequential torsion forward and backward, a thread of the required length is cut.
After the operation is completed, metal filings are removed.
To check the quality of work, you need to screw the intended part onto the pipe.

If everything is in order, the number of turns corresponds to the mating part, you can seal the connection and begin installation of the pipeline system.

Source: https://tepliysezon.com/kak-narezat-naruzhnuyu-rezbu-na-trube/

How and with what to cut a thread on a pipe with your own hands: tools, methods and types of threads

A threaded connection is the most convenient for installing plumbing communications. Its strength indicators are lower compared to welding. But, if you need to replace the pipe, just unscrew the nut and gain access to the entire system.

Most pipes come off the assembly line without a threaded joint. In this case, pipe threads can be cut yourself.

What will be needed for work

In industry, machine equipment is used for cutting, which, without the presence of a driver, copes with centering, moving the die, and subsequent finishing. In an apartment or garage, this is an impossible task.

A special cutting tool is suitable for home use, which can be bought at any hardware store or market. It is presented in the form of collapsible or solid dies and taps.

In addition to the clamp and dies, you will also need an additional tool:

Pipe cutter A tool designed for cutting steel tubes. Equipped with multiple rollers and a carbide or diamond cutter. Gives a thin, almost imperceptible cut, without burrs. If you don’t have one, you can use a grinder with a cutting wheel. Burrs and irregularities appear on the cut that need to be processed.
File or flap circle. If surface defects appear after cutting, additional processing will be required. Since the steel in pipes is raw and soft, it is easy to sharpen it with a file or needle file. To speed up the process, you can use an angle grinder.
Gas burner or hair dryer. If you have to work with an old pipeline, you will have to remove paint and rust. Threading pipes with paint will not provide a tight grip or strength. Old paintwork, most often oil-based, can be easily cleaned with heat. Use a gas torch or hairdryer to walk over the surface and clean everything off with a spatula. Other types of paint require chemical removal. For this purpose, special removers and rust converters are used.

Vise. Since you have to put a lot of effort into cutting, they need to be fixed. It is best to use a plumbing press that has a special jaw profile. But, you can also use a regular bench vise.
Key. If you have to do repairs “on site”, the vice will not work there. In this case, you will need a gas key. It has a large distance between the jaws and allows you to firmly fix the pipe.
Oil. It is advisable to lubricate the part so that it moves along the thread more easily. In this case, you will need a lubricant such as machine oil, WD-40, household grease or petroleum jelly.
Rags. After cutting, it is imperative to remove all dirt from the thread, so after work it is wiped with a rag.

Cutting external threads with a solid die

How to cut threads on a pipe? For this, a special tool is used - a die.

A die is a metal disk consisting of two groups of holes: internal and external (petal).

The internal ones have a threaded notch, which creates slits in the metal. In expensive versions, the threads are made of carbide or coated with diamond coating. Thanks to this, you can even cut through knee steel. But most pipes are made from raw low-carbon ferrous metal. It can be cut with ordinary hardened metal.

Flap holes are designed to drain chips. Since the grooves can be deeper than 1 millimeter, there is a lot of waste that needs to be removed to avoid clogging the cutters.

For low-carbon steel grades, quick-cut dies are suitable. They are harder than the average metal in pipes. For stainless steel water pipes, you will need pobedit water pipes.

As a rule, one strip has from 8 to 10 turns. They are arranged in the shape of a cone. This is required in order to start cutting simply using shallower turns. But the height differences are too small and do not disturb the thread.

Some sets contain several planks of the same size. This is required for roughing and finishing cutting.

A die for cutting threads on pipes can be:

Whole. They have high accuracy since the disk is closed. The absence of movement of the coils prevents the cutting from going astray. But due to solidity, there is a drawback - rapid wear of the cutters.
Separate. They have a slot from the border of the disk to its center. They are used where high precision is not needed, since the groove causes radial movements during operation. Since they have little cushioning, they wear out less.

For convenient rotation, a special knob is used. It has a connector for installing a die and locking screws. Handles are located horizontally for uniform pressure and rotation.

Die cutting process:

The tube is being prepared. It needs to be cut to the required length, the end processed, paint and rust removed.
The tube is fixed in a vice or gas wrench. The die is installed perpendicular to the widened side of the cone. Careful rotations with pressure cut the thread.
The prepared turns are cleaned with a rag. If oil was used, you need to use a solvent.

Using a die with a ratchet holder

The cutting task is greatly simplified if you use ratchet handles. This is a single handle design.

The body itself consists of four parts:

The die itself is installed below. It is fixed with clamping bolts.
In the middle there is a ratchet, to which a handle is welded. A little higher is a switch for switching motion.
A center finder is built into the top.

This design is especially convenient if space is limited and it is not suitable for a two-handed crank. The ratchet allows you to cut with greater comfort. By placing the switch in the screw position, a metal cut occurs. By turning the lever back, the switch is activated and the die does not move.

Below is a video about how the ratchet wrench works.

Application of die dies

A die for cutting threads on pipes is a universal tool, sometimes called a collapsible die. To prepare the work you need:

Install the cutters into their seats. They can be included or purchased separately.
After installing the taps, they are sealed on top with special metal plates.
The head is fixed with screws and the die is ready for use.

The collapsible type of thread cutting tool has high maneuverability, copes well with increased loads and is easy to carry. They are often bought in a set that contains all the necessary cutters.

Thread cutting using a clamp

In the standard set, the die consists of several heads with cutters and a rod for transmitting torque.

The cutting process is simple and does not differ from standard dies. The cutters are cone-shaped, so there are no problems with entering the pipe.

It is advisable to follow several rules for working with a clamp:

Lubrication. For normal cutting you need to use oil or lubricant. To easily remove chips, it is better to use solid oil or other thick liquids that can easily capture metal scraps.
Center. It is important that the alignment is not knocked down. Since cutters are much harder than pipes, it is easy to bevel the thread, causing the thread to become unusable.
Change of rotations. Every half turn, you need to turn the lever back a little.

What about internal threads in pipes?

It was described above how to cut a thread on a pipe. With an internal cut everything is a little different. In a standard pipeline, this is not accepted. Usually, swivel connections are used, since twisting inward will narrow the water supply. This can lead to clogging with metals and minerals.

Sometimes it is difficult to find adapters for the drive in stores, so it has to be made by hand. Taps are used for this. From the outside, they look like bolts, but they have segmented cutters rather than solid ones.

Often sold in pairs, for finishing and roughing work. They are much simpler to work with. They can be done manually using a wrench or a screwdriver.

There is no need to process the hole or remove burrs, but it is advisable to lubricate it.

Types of threads

At the moment, there are several standards for threaded connections used in plumbing. Before cutting threads on a pipe, you need to inquire about their sizes and types.

Two types of threads may not connect to each other, since the angle between the vertices, their length and height will not allow them to fit comfortably.

Metric thread

The name is due to the fact that the measurement takes place in millimeters and the dimensions are indicated in conventional units. The edge has the shape of an equilateral triangle.

In Eurasia this is the most common profile. It is considered a standard, since most plumbing connections are equipped with a metric. Almost all tools for cutting threads on pipes are sharpened specifically for it.

G Straight pipe thread

Cylindrical notching is regulated by GOST 6357-81. Has an inch profile and pitch, common in the USA. If you need to connect the pipeline to American plumbing equipment, you need a special adapter or pipe cutting to profile G.

The letter designation is conventional and indicates the pipe passage in inches.

R pipe tapered thread

Inch pitch pipe with a 1:16 taper. The designation of internal thread is Rc, external thread is R.

Other pipe thread standards

In addition to the categories described above, other sizes will be needed to work with plumbing fixtures.

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In some cases, adapters or tools with rare dimensions may be required. These include:

Inch. The measurement takes place in non-metric units (English imperial measure). One inch is equal to 0.0224 meters. This can be determined by the double quotation marks after the number (1” – 2.54 centimeters). The measure differs from the metric system, so an adapter is needed to fit two types of threads.
Round. Some types of sanitary fittings are equipped with a round notch. These are various types of shut-off elements, mixers and taps.
Trapezoidal. Thread with trapezoidal cross-section and an angle of 30 degrees.

Source: https://kakpravilnosdelat.ru/kak-narezat-rezbu-na-trube-svoimi-rukami-obzor-osnovnyh-sposobov/

Threading a water pipe: tools, preparation and methods

Installation of a water supply system requires the assembly of individual elements into a single system. Metal pipes and shut-off valves are joined with a threaded connection. The method ensures a strong and tight connection. To install communications yourself, you will need tools for cutting threads on water pipes.

Types of threads on pipes

A thread is an alternation of projections and depressions on a surface located along a helical line. It can be external and internal, left and right. Common types:

cylindrical pipe;
pipe conical;
inch cylindrical (US standard);
round;
inch.

In plumbing installation work, the first two types are usually used. They are used to connect water fittings:

Cylindrical (G) – the profile is represented by an isosceles triangle with an apex of 55°. The protrusions and depressions are rounded. Recommended for pipes up to 6 inches in diameter.
Conical (R) - the thread has a triangular profile, forms a taper of 1:16, and is characterized by high tightness of the connection of parts.

Pipe threads can be inch or metric, respectively, measured in inches and millimeters.

Required Tools

To complete the work you will need threading tools:

A die or blade is a device in the form of a nut made of hardened metal, which has pointed cutting edges (cutters). They are round, square and hexagonal in shape. Types of dies: solid, sliding, split. Holes are provided to remove chips.
Klupp is a tool based on a sliding die. The two-part body allows you to adjust the cutting diameter. A handle is provided for ease of use. Some models are equipped with a ratchet that allows you to perform rotational movements with one hand. The professional tool is equipped with an electric drive.
A tap is a hardened steel screw with cutting edges. Consists of a working part and a shank. The set includes devices for roughing and finishing work.

Additionally prepare auxiliary devices:

tape measure and pencil - for measurements and marks;
caliper - determines the diameter of pipes and fixtures.

The tools used must be of high quality, the metal of the cutters must be sharp and durable. When working with dies and taps, you will need a vice.

Preparing for work

The area where you will have to work with a thread-cutting device for water pipes is cleaned of rust, dirt, and paint residues. Sandpaper is used. The surface should be cleaned to a metallic shine. The end surface is chamfered. It is necessary to prepare a lubricant for processing the pipe and cutting tool. You will need a rag to clean the shavings.

Methods for cutting threads on a water pipe

Cutting methods are divided into two types: manual and automatic. In the first case, you will need a set of thread-cutting devices. Dies are used for cutting external threads, and taps are used for internal threads. Tool sizes are determined using reference tables. Automatic cutting occurs on machines or power tools. The method is accurate and suitable for pipes of any diameter. The machines perform milling and thread rolling.

Die cutting

The choice of tool type depends on the quality requirements. The best result is achieved when using a solid die, which has high rigidity. The disadvantage of the device is rapid wear. Spring-loaded dies (with a cut in one of the axial holes) allow you to change the thread diameter within 0.3 mm. Their rigidity is reduced, the incisors last longer, but the purity of the threads is lost.

The prepared pipe is clamped in a vice. The die is placed in the holder and secured with screws. Lubricant is applied to the treated area and cutters. The tool is placed on the pipe at a right angle. Rotation occurs smoothly, clockwise. After making several turns, the chips are removed and lubrication is restored. For high-quality cutting, a finishing die is used after the roughing die. The finished thread is cleaned with a rag.

Using the Clupp

Using a pipe clamp is more convenient than using dies. The tool is more expensive, but for doing a large amount of work it is better to choose it. The clamp gives a clean turn, the sliding design allows you to adjust the thread diameter.

Installing guides reduces the risk of distortions and facilitates the cutting process. If the design includes a ratchet, a ratchet wheel is placed near the die. When it turns, the tool head moves.

The ratchet is indispensable in cramped working conditions.

The pipe is clamped in a vice, leaving a small section. The short protruding part will not allow the metal to bend from the applied forces. The pipe and cutters are lubricated with machine oil. The protruding part is inserted into the die guide. Cutting occurs with short rotational movements. It is periodically rotated back to cut off chips. Lubricant is added during operation. When cutting threads on water pipes, it is important to monitor the number of turns.

Using an electric tool allows you to cut in a few seconds. Replaceable heads with cutters are selected to match the required pipe diameter. The work is not only fast, but also of high quality.

Working as a tapper

Internal threads are made with a tap. Its diameter should be slightly larger than the pipe. When working, it is recommended to use a set of two or three parts. They perform rough and finishing cuts. The first tool does the main work, removing up to 70% of the chips. The finishing tap has a small chamfer and a full cutting profile. Tools are distinguished by grooves on the shank:

one is black;
two – average;
three – finishing.

The inside of the pipe requires cleaning and lubrication. The tap is inserted vertically, the shank is secured in the driver. Rotation is clockwise. When working with soft metal, the tool is periodically turned out and the chips are cleaned out. Lubricant must be used. After completion of the work, the quality of the thread is checked.

Main reasons for marriage

The cause of defects in work is the inattention of the worker or the use of low-quality tools. Common pipe cutting defects when working with a tap or die:

Torn threads - a problem occurs when using a dull die, untimely removal of chips, or insufficient lubrication.
Incomplete thread - the diameter of the thread hole exceeds the recommended one.
Skewed helical grooves – incorrect installation of the die or tap.
Thread failure is caused by clogging of the grooves with chips, poor quality of the tool, or the pipe diameter is larger than specified.
Tap failure - excessive force applied in a narrow hole, insufficient chip removal, lack of lubrication.

Self-preparation of parts for threaded connections is quite accessible if you have the tools. In order for the work to be done efficiently, you must follow the rules. The use of sharp tools and accuracy compensate for the lack of professional skills.

Source: https://StrojDvor.ru/vodosnabzhenie/narezka-rezby-na-vodoprovodnoj-trube/

Thread cutting. Necessary concepts

This process is the processing of a rod or hole using a special tool for cutting threads on pipes in order to obtain external or internal alternating protrusions-turns and spiral grooves.

The main characteristics of the thread are:

step. This is the distance between the tops or bases of adjacent turns;
profile. The cross-section of the coil can be trapezoidal, triangular, rectangular, etc. In the details of sanitary systems, exclusively triangular profiles are used ;
profile angle. It is formed by the intersecting sides (side faces) of the turns;
depth. This is the distance from the top to the bottom of the thread;
outer, middle and inner diameters.

Outer is equal to the distance between the points of two opposite sides of the thread. Average diameter ˗ is the distance between the top and bottom of the profiles, which are on opposite sides of the part. Internal represents the distance between opposite depressions.

Any thread has its own technical characteristics

Tools and rules for cutting threads on pipes

Of course, to perform this procedure, you cannot do without a pipe threading tool. In the trade, it is usually called a pipe threading set.

Helpful information! The set may include a tool with an unusual clamp name. It resembles a die for cutting threads on pipes, but contains only its main functional part - a round frame in the form of a short cylinder made of tool steel and equipped with durable cutters.

In addition to dies or clamps, the set includes a holder (with or without a ratchet), as well as a number of other additional tools, such as pliers, a clamp, etc.

The requirements for the manual pipe threading process are formulated as follows:

mandatory pipe preparation. It is necessary to remove dirt, rust and a layer of paint from the site of future carving. The surface should be cleaned down to metal ;
The process of cutting threads on pipes must be accompanied by lubrication of their working surfaces and the cutters of the tool used - a die or clamp. For this, a lubricant is used, which is a special liquid. It is applied both before and during the threading process on the pipe;
at the end of the product it is first necessary to remove the outer chamfer;
work should only be carried out with a sharp and serviceable tool for cutting threads on water pipes.

In addition to technology, it is also important to know the subtleties of choosing a tool.

When cutting threads, you must strictly follow the technology

Threading tools are not only the above-mentioned dies and dies, but also taps. With the help of the latter, an internal thread is created by cutting chip grooves. But there is one nuance here. To cut threads on a pipe, you must use a set of two taps that differ in cutting depth:

for rough work - No. 1;
for finishing work - No. 2.

The die for cutting threads on pipes is:

round;
sliding;
split;
whole.

Another tool, the clamp, has a guide in its design. It serves to center the cylinder with cutters along the pipe.

At the same time, just knowing what threads are used to cut a water pipe is not enough. It is necessary to find out the GOST requirements for the size of pipe threads, and in accordance with its pitch and diameter, select a set of threading tools. These data are presented in the table below.

Table 1

Thread pitch	Thread diameter, mm	Pipe thread size, inches
mm	Threads 1 inch	Interior	Outer
2,309	11,0	84,930	87,887	3
2,309	11,0	72,230	75,187	2 1/2
2,309	11,0	56,659	59,616	2
2.309	11,0	44,847	47,805	1 1/2
2,309	11.0	38,954	41,912	1 1/4
2,309	11,0	30,293	33,250	1
1,814	14,0	24,119	26,442	3/4
1,814	14,0	18,632	20,956	1/2

Steps for cutting pipe threads by hand

As mentioned above, this operation is performed using a die, die or tap. The choice of pipe threading kit depends on many factors. But, first of all, it depends on what kind of thread needs to be created - external or internal. To be more specific, let’s look at how a thread is cut onto a stainless pipe manually using a die.

Cut off the part of the stainless pipe that has the old threads. It is not advisable to restore it, since it will be impossible to achieve complete tightness of the connection and, therefore, leaks will occur in this place. When performing this operation manually, pay special attention to the cut. It must be strictly perpendicular to the longitudinal axis of the pipe.

Important! A pipeline segment with signs of corrosion must also be removed.

To make it easier to screw on the die, remove the chamfer from the end of the pipe. To ensure better glide, lubricate the future thread with oil. Next, begin the actual cutting of the pipe threads. After completing a certain number of turns, the die should be twisted in the opposite direction.

Using a die it is easy to cut external threads

Once you have completed cutting the pipe thread, remove any metal filings from the newly created joint. To check that the work was performed correctly, screw the object to be installed onto the pipe.

This way you will find out whether the selected die is used correctly for cutting threads on pipes, as well as whether the number of turns is sufficient.

If the test is successful, seal the connection and proceed with the installation of the plumbing system.

Advantages of clamps

Some features of this tool used for cutting threads on pipes have been mentioned above. But ease of use is far from the only advantage of such a set.

So, for example, knowing in practice how to cut a thread on a pipe using a die, you can easily cope with this task using a die.

Other advantages include the cleanliness of the resulting thread, the simplicity of the die design, the ability to quickly replace cutting dies, and low weight.

The following factor deserves special attention. Expensive tool steel is used to make the die.

But only the cutters, which actually do the main work, should have increased strength! The absence of expensive non-functional parts leads to a reduction in the price of a set of clamps and, accordingly, reduces the cost of the thread cutting process on a stainless pipe. Therefore, home craftsmen who know how to count money give preference to just such a tool.

The use of a die will greatly facilitate the task of cutting threads.

These products are sold with a set of dies for cutting threads on pipes with a diameter of 50, 38, 32, 25, 20 and 15 mm. Each of them is designated by the number 1, 2, 3, or 4.

All slots on the die body also have numbers corresponding to the cutting dies that will be used to cut threads on the pipe.

To increase the efficiency of work in hard-to-reach places, it is recommended to purchase special equipment together with the clamp.

Today on the market you can find such a tool with electric and manual drive. Therefore, the question may arise as to what is used to cut threads on a pipe more efficiently.

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Helpful information! Clips are sold in specialized both stationary and online stores. The latter are very convenient, since you can become the owner of a suitable set for cutting threads on pipes without leaving your home.

Professional mechanics who know exactly how to cut threads on a pipe prefer electrical plugs. But such devices cost more. Therefore, if you plan to carry out one-time threading on a pipe, it is more profitable to purchase a set of tools with a manual drive.

Source: https://varimtutru.com/kak-narezat-naruzhnuyu-rezbu-na-trube/

Rules for threading pipes - possible options

To assemble modern pipelines, pipes made of plastic or metal can be used, and a welding machine is used to connect plastic pipes. As for metal products, their assembly involves the presence of threaded fittings: this ensures maximum connection strength. To implement this method, threads will need to be cut on the pipes themselves.

What tool do you need?

Threading pipes will require the following equipment:

Tape measure, pencil, caliper . To assemble the pipeline, it is necessary to develop a diagram in advance. First, a pipe with the specified length is taken: markings are made with a tape measure and a pencil. Using a caliper, the diameter is measured and suitable devices are selected. When marking, it is important to maintain considerable precision and accuracy, since any deviation from the specified size leads to a violation of the correctness of the entire structure. As a result, in such cases it is often necessary to redo the entire pipeline.
Bulgarian . Using this tool, pipes are cut according to the marked marks. A simple hacksaw for metal can perform the same functions.
Vise . During operation, the pipe must be securely fixed in a strictly horizontal position.
Machine oil or other lubricant . To facilitate manual thread cutting, it is practiced to lubricate the tool and the area being processed with a special substance.
Thread cutting tools . Pipe threads can be cut with a die, a die or a tap. Which tool to use depends on the type of thread being cut and the preferences of the performer. For different jobs, different pipe threading kits are used, depending on the situation. The external thread is cut with a die, which is held by a die or die holder. To apply internal threads you will need taps.

Do-it-yourself thread cutting

How to cut pipe threads yourself?

Self-threading begins with a number of preparatory measures:

Cutting a piece of pipe to size . When replacing a damaged section of a pipeline, the first step is to carefully cut out this section in a direction strictly perpendicular to the wall. If this condition is not met.
Cleaning the thread area . From the place where the pipe thread will be cut, all paint and corrosion must be completely removed: if this is not done, the work can be clearly difficult.
Chamfering . To make the work easier, you need to remove the chamfer from the ends of the pipe.

Thread cutting using a die

The die is used for cutting external threads, which requires the following operations:

Select a die with the required diameter. To make the selection correctly, you must definitely check it with a caliper.
Lubricating the internal cavity of the clamp and the prepared area on the pipe using machine oil.

Source: https://trubaspec.com/montazh-i-remont/pravila-narezaniya-rezby-na-trubakh-vozmozhnye-varianty.html

Cutting external and internal threads on pipes: tools, technologies

Threading a pipe is the processing of its internal or external surface to produce alternating helical grooves and protrusions. Threads are formed on pipes, fasteners, and equipment parts.

Main characteristics of threads

To determine the thread size, the following parameters are used:

Profile – rectangular, triangular, trapezoidal. The triangular profile is used when installing sanitary systems.
Profile angle – formed by the side edges of the turns.
Direction – right or left. With the left one, the nut is screwed onto the bolt counterclockwise, with the right one - clockwise. The right one is much more common.
Pitch is the distance between the tops or bases of adjacent turns.
Depth is the length of the segment from the top to the deepest point.
Internal diameter is the distance between the thread bases located at opposite points of the cross-section of a rod or hole.
Outer diameter is the distance between the thread tips located on opposite sides.
The average diameter is the size of the segment between the top and the base, lying on opposite sides.

According to the system of measures, triangular threads are divided into metric and inch.

Metric

They have the shape of an equilateral triangle with angles of 60°. The internal and external diameters are indicated in millimeters, the pitch - in millimeters and their fractions.

Inch

The profile is similar to metric threads, but the apex angle is not 60°, but 55°. The size is expressed in inches, the pitch differs from its metric counterparts. Threads are divided into pipe and fastening threads; they are in demand when installing plumbing systems. The fastener has a large pitch, is used for nuts, bolts, studs, holes, and guarantees reliable joining of parts. Pipe has a smaller pitch and is used to connect pipes.

Basic rules for cutting pipe threads by hand

A thread-cutting set is designed for cutting external threads manually. It consists of:

dies or die - frames, which are a cylinder made of tool steel, equipped with durable cutters;
holder with or without ratchet;
pliers, clamps and other auxiliary tools.

Taps are used to make internal threads.

Basic requirements that must be met when cutting threads by hand:

surface cleaning;
the working surfaces of the tool and the processed elements are lubricated with special liquids;
the instrument must be in full working order.

How to choose a tool for cutting external threads at home?

To make external threads on a pipe, a die is used - a piece made of tool steel that has a rounded shape. There are cutting edges inside it. Using a special holder, a double handle is attached to it, providing convenient rotation. The pipe die is an improved version of the die.

Its feature is the saving of expensive steel grades, since the working element is placed in a holder made of cheaper metal. An additional plus is the single handle, which allows you to cut threads in hard-to-reach places. The cutters in the die are replaceable parts that can be purchased separately as they wear out.

Advice! It is recommended to purchase cutters from the same manufacturer as the tool. If this is not possible, then you should take the holder with you to the store to make sure that the body and cutting parts fit together accurately.

The type of clamp is chosen depending on the amount of work and personal preferences.

The simplest hand tool consists of a holder with cutters fixed in it and a handle, which in the cheapest models is not included in the basic kit. To rotate the clamp without a handle, you will need a pipe wrench. The handles can be rotated with two hands or with one. The second option is more convenient for working in cramped conditions. With this compact and inexpensive tool you can carry out work in small quantities.
Manual clamp with ratchet. The tool is convenient in that it is not necessary to remove the handle after each turn of the holder. This option is more financially expensive compared to the previous one, but more convenient, reliable and productive.
Electric models are easy to use and allow you to carry out large-scale work. Significant disadvantages are: inability to use in hard-to-reach places, the need for a nearby power source, dependence on weather conditions when working outdoors.

To simplify the process of making threads, apply a little diesel fuel or grease to the contacting surfaces.

Approximate scheme of work

The clamp is put on the pipe and fixed.
Rotate the handle while pressing simultaneously.
When working with old pipelines, in order to avoid breaking off part of the pipe, the stress from rotational movements is compensated using a pipe wrench.

Features of cutting internal threads on a pipe using a tap

To make internal threads on a pipe, a tap shaped like a rod with a cutting element is used. Inserted into the collar. Structural parts of the tool:

fence - has the shape of a cone, produces cutting (cutting teeth are incisors located in a circle);
calibrating - has the form of a cylinder with teeth, which are a continuation of the teeth of the intake part;
tail with a square head - holds the tap in the gate or chuck of the machine.

Recommended Cooling Media:

for aluminum and alloys based on it - kerosene;
for copper - turpentine;
for steel – emulsion.

If there is no or insufficient amount of coolant, a rough or uneven profile may form.

Source: https://www.navigator-beton.ru/articles/narezka-rezby-na-trubah.html

How to cut threads on a pipe

To cut threads on various pipes, the performer must have an understanding of the features of the process and have a certain skill. In our material we will explain to you how to freely cut threads at home.

Having mastered this process, you will be able to repair any household appliances, plumbing, heating networks - in short, any systems containing threaded connections on pipes.

Thread cutting methods

The technology of the pipe threading process includes various methods:

the use of special threaded dies and cutters;
knurling using flat or round dies;
use of threading heads, taps or dies;
milling with special cutters.

Accordingly, the thread cutting process requires the presence of special tools and devices. In this material we will step by step consider the method of cutting threads with a die - a special thread-cutting kit.

Tool composition

A die is a special device for cutting threads, equipped with several sets of cutting radial dies. They have different diameters, suitable for a particular sewer or water pipe.

In addition to the clamp you will need:

a set of taps for cutting internal threads;
gas wrench or vice for fixing the pipe;
machine oil or any other;
grinding machine for metal processing with a cutting disc.

Note! When working with a grinder, you need to protect your eyes and hands with special glasses and gloves.

Sequence of operations when cutting external threads

First you need to make sure that the pipe is in good condition and will not break when threading. If the pipe is painted, then it must be stripped of the paint layer.

We mark the place of the cut on the pipe and use a grinder to cut off the unnecessary piece of pipe perpendicularly, having previously fixed it with a vice or a gas wrench.
A chamfer is cut off at the edge of the pipe - this will simplify the process of screwing on the die. It is better to lubricate the place of the future thread and the teeth of the die with oil, or at least regular lard, for easy sliding. Next, we proceed directly to cutting the thread.

Usually two dies are used - a through dies, or a roughing one, the cutters of which only form the profile and a finishing one, cutting the thread directly. This, firstly, facilitates the cutting process itself, and secondly, reduces wear on the tool itself. We press the die holder with the pass-through die attached to it with force against the pipe so that an engagement is created.

Then rotate the holder clockwise. After making several turns, usually five turns, we change the direction of rotation to the opposite, turn half a turn back to clear the threaded groove from chips. The chips will break off and it will be easier to cut, then turn clockwise again.

It will be correct to cut the first thread with a guide bushing so that the thread does not become skewed. The bushing must have an internal diameter that matches the external diameter of the thread being cut. A die holder can be used to secure it. This improvement will ensure that the threads are aligned with the pipe.

Next, we begin to work with the finishing die, not forgetting to first lubricate its teeth. For greater force, you can lengthen the handle of the holder. It is very important not to try to do all the work in one pass. You need to move half a turn, gradually. Otherwise, you can bend the pipe and break the die.

You should not cut threads longer than 1 cm: this is the length of the threads of most elements of household water supply networks. At the end of the process, the freshly cut thread must be cleaned of chips and wiped of oil.

Internal thread cutting

This thread is cut with a tap. To select it, you need to know the exact size of the thread hole. If it is blind, then its length should be several millimeters longer than the required thread.

The hole is pre-drilled with a drill to remove the excess layer of metal and facilitate threading. It is better to select the required diameter using reference tables. But, you can make a rough calculation: it should be equal to the difference between the thread diameter and its pitch.

Then the cutting itself is performed directly in two passes: first, about 70% of the chips are removed with a rough tap, then with a finishing tap, the remaining 30%. The rotation of the taps is carried out clockwise using a “wrench” - a special tool for holding them.

Before operation, the taps must be lubricated with machine oil.

In this way, you can independently obtain a high-quality threaded fitting.

Source: https://positroika-doma.ru/inzhenernye-sistemy/kak-narezat-rezbu-na-trube

Tool for cutting threads on water pipes

Any repair or replacement of an existing pipeline involves cutting into the main line. Welding is only suitable for metal pipes, while this method cannot be used to connect them to plastic products. In addition, during installation, shut-off valves are used, which are secured with a threaded connection. To create it, you need to know how to cut a thread on a pipe and with what tools.

There are several types of tools for thread cutting

How to cut a thread with a die?

If it is necessary to manually cut external threads for a pipe connection, make a stud or bolt for a nut with a metric thread, a simple but quite effective tool is most often used - a die. The thread preparation process is quite simple if you follow the instructions below exactly.

THIS IS INTERESTING: How to properly cut a thread on a pipe with a die

Preparing to cut threads with a die

Before cutting a thread with a die on a rod or pipe, you need to select a tool of the required diameter and pitch. The die itself is a nut with conical cutting teeth with holes for fastening in the collar.

The dies can be solid, split, sliding, round, square or hexagonal.

First of all, you need to select the material and tool of the required diameter.

Below is a table of correspondence between the most popular diameters for metric, imperial and pipe threads with an example of selecting a workpiece for an M6 thread

As we can see from the table, to cut an M6 thread we need a rod with a diameter of 5.8 mm. For larger thread diameters, there is an acceptable minimum and maximum value for the rod thickness. You cannot violate it - if the diameter is exceeded, you risk breaking the die; if the value is less than the minimum, you will get a weak thread.

Before you start cutting external threads with a die, in addition to the tool itself and the workpiece, you need a driver suitable in shape and size, as well as machine oil. After this, you can proceed directly to the cutting itself.

Thread cutting order

Before cutting, it is necessary to chamfer the outer part of the pipe or workpiece at an angle of 45°. This is necessary to facilitate the first turns and fix the die.

Further actions:

Secure the pipe or workpiece in a strictly vertical position. The best option to avoid distortions is a bench vise, but you can also use a gas wrench.
Lubricate the tool with oil.
Place the die on the head of the rod in a strictly horizontal position and start with the first few circles.
If there is obvious misalignment in the first laps, remove the die, tap the workpiece and start again.
When rotating on the first turns, simultaneously press evenly on the handles of the driver to begin the cutting process.
After the first few turns, check that the thread is cut correctly. This can be done by checking the horizontality of the dies and the knob, which can be checked with a level. Next, with the correct position of the tool, you can continue cutting the pipe thread with a die to the entire required length.
When approximately the middle of the length is reached, the pressing force can be weakened, then the self-tightening process begins.
After one or two turns, it is necessary to turn the die half a turn back to remove chips.
After cutting to the desired length, simply return the tool back along the finished thread.

It is necessary to take into account that the die can have several numbers, most often 2. In this case, after cutting the rough thread, it is necessary to go through each of the numbers in turn to finally form the thread profile.

Source: https://mekkain.ru/stati/kak-narezat-rezbu-plashkoj.html

Cutting threads on a pipe is not that difficult

Articles

In order to securely connect a tap to a pipe, or install a heating device in a heating system, it is important to know how and with what to cut a thread on a pipe.

After all, most shut-off valves have threads; accordingly, connecting such elements by welding is impossible.

Thread on a water pipe

For example, if you have to install a new washbasin or toilet in your apartment, and it is not possible to unscrew a long-term connection on a steel water supply system, then the best option is:

Turn off the water supply;
Using a grinder, cut off part of the pipe near the installation site of the washbasin;
Cut pipe threads;
Install a ball valve or tee on the pipe;
Connect it with a flexible hose to the washbasin tap.

This work can easily be carried out by a qualified plumber. However, any apartment owner, having purchased a tool for cutting threads on pipes, is able to carry out this work independently.

Threading dies

Today, to equip a pipe with a threaded connection, 2 types of thread-cutting devices are used:

Threading dies;
Pipe clamp.

With their help, you can cut threads on any sewer or water pipe that is used in the utility networks of residential buildings and private cottages.

Pipe clamp

Advice!

If you have never cut a thread, it will be difficult to do it with a die. The slightest misalignment of the tool can lead to a defect.

Therefore, it is better to use a clamp, since it has a guide that greatly simplifies the cutting process.

Let's brush up on the theory behind the threading process.

So:

threading on pipes is the formation of a screw surface on the outside of a pipe (plumbing or heating system);
the screw surface is a connecting element rotating uniformly around the axis of the fitting,
tee or tap, with uniform translational movement along this axis;
thread pitch is the translational movement of the screwed element relative to the thread axis, corresponding to one full revolution.

In other words, in order to install shut-off valves, it is necessary to cut a thread on the pipes, the pitch of which coincides with the pitch of the connecting elements. Then such a connection of sewer or water pipes will be sealed and durable, and able to withstand high pressure.

Thread cutting work

To carry out this operation yourself, you need to purchase a pipe threading set. These can be either dies of the required diameter, or a more practical set of dies.

Basic requirements before starting work:

before threading, the pipe must be cleaned of rust and old paint;
the lead-in chamfer must be removed on its end surface;
use only high-quality cutting tools in your work;
It is imperative to have lubricant for efficient operation of the cutting tool and removal of chips.

Caution: pipe threading dies require some skill. Therefore, before starting work, you should practice on a piece of an old pipe so as not to spoil the water supply or sewer system.

Professional pipe threading kit

Preparatory work for cleaning the pipe and chamfering is best done using sandpaper and a file:

thoroughly clean the surface of the pipe to a metallic shine;
Use a file to chamfer the end of the pipe.

Cleaning the pipe before threading

The next stage is direct threading, which differs in the sequence of actions, depending on the selected tools.

Using dies

If you purchased dies for cutting pipe threads and a die holder, then the procedure will be as follows:

we clamp the pipes in a vice, or fix them in a convenient way so that the pipe remains motionless during the cutting process;
install the die into the die holder and fix it with screws;
apply oil to the pipe and to the cutting edges of the die;
carefully place the tool on the pipe and, rotating clockwise, cut the first thread pitch;
We make sure that the tool is perpendicular to the pipe;
Having cut the thread to the required length, unscrew the die and run it again.

Thread cutting with a die

Application of the clamp

A simpler version of thread cutting can be achieved using a die. This is a modernized die, equipped with a special guide and ratchet. Most often sold as a pipe threading kit.

The cutting process will be as follows:

install a screw of the required diameter from the purchased set into the ratchet;
apply oil to the cutting edges;
We put the guide on the edge of the pipe;
we begin to twist the ratchet, cutting the thread;
lubricate the pipe and cutting edges during operation.

Cutting pipe threads using a clamp

How to cut a thread with a die or tap, incl. on pipes

A threaded connection is one of the most common methods of fastening various parts. Today there are many varieties of bolts, nuts, screws, etc., but sometimes there are situations in which you need to cut threads yourself, for example, in a hole made in metal or on a metal water pipe.

There are several tools and thread cutting methods for this, let's look at them.

:
1. Types of thread.
2. Educational program: what you need to know when cutting threads by hand.
3. How to cut external threads using a die.
3.1 The principle of cutting threads with a die.
3.

3 Cut the thread with a die with your own hands (video).
4. Cutting internal threads with a tap.
4.1 Manual cutting of internal threads with a tap (video).
5. Cutting threads on a metal pipe with your own hands.
5.1 Cutting external threads on a pipe using a die (die).
5.2 What is a clamp and how to use it (video).

5.3 Cutting internal threads on a pipe with a tap.

Types of thread

The carving is:

Metric
Inch
Pipe inch

How they differ can be seen in the picture below; the only thing worth noting is that metric threads are mainly used.

Types of thread

There is also a difference between right and left threads.

How to cut external threads using a die

To cut external threads manually, a special tool is used - a die holder with dies of various diameters.

Die holder with dies for different diameters

In hard-to-reach places, for example near walls, a die holder with a ratchet is used.

Selection of dies

Nominal thread diameter is the diameter at the vertices of the thread triangles. The die cuts the metal, forming depressions and leaving the tops intact, thus both the rod and the die must be the same diameter. The diameter of the thread, for example, is M3 - this is “M” - metric thread, and the number is the nominal diameter of the thread in mm. Accordingly, to cut a thread on a 3 mm rod, we take an M3 die. Measurements of the rod are made with a caliper.

To make the die cut better into the rod, a chamfer is cut off from its end.

Principle of thread cutting with a die

To secure the workpiece you will need a vice. The workpiece is firmly fixed in a vice and lubricated with machine oil for easier movement of the die, reducing friction and tool wear.

When cutting threads with a die, you must avoid large accumulations of chips in the chip removal holes.

The die is installed on the end of the part perpendicularly. With slight pressure, they begin to rotate the die holder clockwise if the thread is right-handed, respectively, if it is left-handed, then counterclockwise.

Cut the thread as follows:

First make 2-3 turns.
Then half a turn back to remove chips.
Lubricate after every 3-4 turns, using a syringe.
Etc.

Source: https://chonemuzhik.ru/kak-narezat-rezbu-plashkoj-ili-metchikom-vt-ch-na-trubax.html

How to cut threads on pipes

› To the master

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An easy way to cut threads on a metal pipe

I will show you how easy it is to cut a thread on a water pipe for an ordinary home craftsman, without any skills in this matter and with a minimal set of tools.
For example, when replacing a central heating battery, as in my case. There is absolutely nothing complicated about this and the method is accessible to almost everyone. So, you cut the pipe with a grinder or other tool, such as a hacksaw. The main thing is that the cut is even and perpendicular.

Will need

Clamp for the required pipe diameter.
Adjustable wrench (gas).

Klupp is a thread-cutting tool, like a die, only it is an attachment with a guide skirt. It must be purchased from a plumbing store. There is no shortage of them, so you can find them without problems, even in the village.

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

Such a thing costs around 200-500 rubles. It all depends on the diameter and markup. Running models with diameters of 1/2, 3/4 inches and inch, as in my version.

You can ask plumbers for a Soviet equivalent, if possible. Then it will be completely free for you.

Cutting a thread on a pipe

You don't have to remove the old paint. We lubricate the place where the thread will be with solid or liquid lubricant: grease, lithol, engine oil.

We also coat the cutters on the die.

In neither case do you need to apply a lot of solid lubricant, since after cutting the chips will stick to it and will not fall down, and therefore be removed.
We put the guide clamp on the pipe.

In theory, the clamp is rotated with a specialized tool - a ratchet, but since we have a one-time job, it will not be profitable to purchase an expensive tool. We take an adjustable wrench and adjust its size to the rear skirt of the clamp.

Rotate the tool, making several turns around the pipe. The cutters are now engaged.

If the pipe is flimsy and unstable, it needs to be held with another adjustable wrench like this:

And use another adjustable wrench to rotate the nozzle.
The cutting sequence is as follows: 2-3 turns of the die forward, 1 turn back. This must be done so that the chips break, fall off and do not interfere with further cutting. If this is neglected, chips can jam the threads.

In total, you need to cut 4-5 full turns of thread.

As a result, the thread on the pipe is cut.

Also keep in mind that the cutters in the die have a small cone. This is necessary so that you can start and cut threads with ease. As a result, I lead to the fact that the final turns may not be complete and not cut in depth. Therefore, in order to get 3-4 full turns of thread on a pipe, it is visually better to cut 6-7 turns.

After all the work, the thread can be checked by screwing any adapter or fitting onto it.

The thicker the pipe, the greater the force required to rotate the nozzle. The method is not tricky, almost no proper skills are required, even a beginner can do it. It is impossible to skew the thread, so there is no need to be afraid.