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

How to cut threads by hand

Threaded connections are widely used in various mechanisms and machines. Bolts, studs, screws, nuts are universal, interchangeable fasteners. However, there are times when it is necessary to cut threads by hand. A specialized tool will help you do this job efficiently.

In mechanical engineering, there are three main systems of fastening threads: metric, inch and pipe.

Metric thread has become the most widespread. It has a triangular profile with an angle of 60˚. Its main parameters, diameter and pitch, are expressed in millimeters. Designation example: M16. This means that the thread is metric, has a diameter of 16 mm with a coarse pitch of 2.0 mm. If the step is small, then its value is indicated, for example, M16 * 1.5.

The diameters of inch and pipe threads are expressed in inches. The pitch is characterized by the number of threads per inch. The specified parameters are standardized, so it is always possible to select the necessary tool.

Types of dies

There are simply a huge number of different versions of the tool, which is associated with the variety of threaded connections. They all have their own specific advantages and disadvantages.

Types of dies are taken into account to select the most suitable version for thread cutting. The main characteristics of the classification are as follows:

1. Form.
2. Housing design.
3. Method of cutting turns.

In addition, do not forget that there are metric and inch dies. Metric threads are more common, but inch threads are used to create various mechanisms.

Metric thread cutting die

The classification of thread cutting dies by shape is as follows:

1. In the form of a hexagon.
2. Tubular.
3. Round.
4. In the form of a square.

There are also several types of tools based on design characteristics:

1. The one-piece die is left-handed, the thread can be with different pitches, it is represented by a non-separable cast body, which has several holes. This version is the most widely used, as it is characterized by reliability, ease of use, and long service life. However, if you frequently work with different diameters, you have to have a whole set of this tool with you.
2. Split ones significantly simplify the process of cutting turns, which is also related to the design features of the body.
3. Sliding versions have the most complex body, which can be adjusted within a certain range of diameters. Having one similar tool available, you can cut threaded surfaces on workpieces of various diameters.

Inch thread cutting die

Left-handed threads can be used with all common tool options. By purpose, the following classification can be distinguished:

1. For round threads.
2. For conical shape.
3. For cylindrical.

Manufacturing is carried out in accordance with established standards in GOST.

External thread cutting with a die

To cut external threads, you will need the following tools and materials: a die or pipe clamp, a die holder, a file, a vice, a caliper, and machine oil.

The most widespread are round dies (lerks). They are either solid or split. The diameters of solid round dies are standardized. This allows you to choose the appropriate option from a large range of sizes, for example, M10, M12, M14, M16.

A special feature of split dies is the ability to adjust the diameter of the thread being cut within 0.1…0.25 mm. However, they have reduced rigidity, which affects the accuracy of the resulting profile.

The die is installed in a die holder of a suitable size. After this, it is secured with screws. In the case of external pipe threads, die holders with a ratchet are often used. They provide convenience for working in hard-to-reach places, such as near a wall.

The thickness of the rod is chosen to be 0.1...0.25 mm less than the diameter of the external thread. For example, for M6 with a large pitch it is 5.80...5.90 mm; M8 – 7.80…7.90 mm; M10 – 9.75…9.85 mm. Measurements are taken using a caliper. The diameters of rods for cutting metric threads of average accuracy class 6g are presented in the table.

To ensure better insertion of the die, a chamfer is filed at the end of the rod. Its width should be 1 - 1.5 mm for M6 ... M18. The workpiece is lubricated with machine oil, which makes subsequent work easier and allows you to obtain a better surface.

The die is placed on the end of the rod so that its plane is perpendicular to the axis of the bolt being cut. Next, with slight pressure, rotate the die holder clockwise (if the thread is left-handed, then counterclockwise). When the die cuts into the rod by one or two threads, it should be turned back half a turn for better removal of chips. After this, they again make 1-2 turns along the thread and 0.5 in the opposite direction. Using this scheme, the bolt is cut to the required length.

The diameter of the external thread is checked with a regular nut or ring gauge. If necessary, the pitch is controlled with a thread gauge.

External thread cutting

An integral part of any threaded connection is the externally threaded component. It is he who screws into the hole with internal threads. Rotating bodies, that is, shafts, are equipped with an external threaded surface. This type of thread is typical for bolts, studs, lead screws, all kinds of couplings and adapters.

A special tool is used to cut external threads:

1. Die
2. Die holder

As is clear, the die is inserted into the die holder. The die fixed in the holder is placed on the tip of the chamfered shaft. Next, the die is pressed down and screwed onto the shaft.

The height of the dies depends on the diameter of the thread being cut. On average, a die has 8 helical grooves. If we consider dies for cutting metric threads, the industry offers dies from M3-M6 to M52. In addition to dies for cutting traditional metric threads, there are dies for pipe (inch) threads, which can be either cylindrical or conical.

A type of dies is lerka. The key difference between lerks and dies is the design. The lerka is presented as a one-piece product. The die can have a split or sliding design.

Of course, the split die can also be used for direct thread cutting. But due to the spring design, the accuracy of the threaded surface will be far from ideal. As a rule, the first, so-called “roughing” pass is made with a split die.

Sliding dies have a collapsible design. If in split dies the cut is made only on one side of the product, then in sliding analogues the die is cut into 2 equal parts.

Sliding type dies usually have a prismatic shape. To work with such dies, you should use a die with a clamping mechanism.

Sliding dies are characterized by increased durability. Thanks to the collapsible design, the cutting edges can “play” under critical loads. This avoids the appearance of chips and cracks on the threaded grooves.

Of course, the collapsible design of the dies affects the accuracy of thread cutting. Usually, with the help of a collapsible prismatic die, it is possible to achieve 6-7 quality accuracy, while non-separable analogues provide the ability to obtain threads of 8-9 quality.

Solid lerks are cast one-piece dies. The main advantage of the lehr is the ability to cut threads with a high degree of accuracy. The good quality of the resulting thread is due to the non-demountable rigid structure.

Regarding weak points, the lehrs have them. The high rigidity of the structure makes such dies susceptible to chips and cracks. The cut edges in lehrs often become chipped. Leathers are significantly inferior in durability to split and sliding analogues. When using a lehr, it is recommended to use plenty of lubrication. Cooling won't hurt either.

Tapping internal threads

To form an internal thread, the following tools and materials are required:

• hammer, center punch, drill, drill bits;
• a set of taps, a driver, a bench vice;
• machine oil.

Tapping technology

The first step is to mark the workpiece and core the center of the future hole. Select a drill corresponding to the required thread diameter. This can be done using lookup tables or approximately using the formula d = D – P. Here D is the thread diameter, P is its pitch, d is the drill diameter. For example, for M10 d = 10 – 1.5 = 8.5 mm.

A hole is drilled into the part to the required depth, which must exceed the length of the part being cut. Using a drill with a diameter larger than d, a chamfer is made on the edge of the hole. It serves for centering and better entry of the tap.

The cutting tool is selected based on the main parameters of the thread - diameter and pitch. As a rule, a set of two taps is used. One of them is rough, the other is finishing. The driver is selected according to the size of the square of the tail part of the taps.

The part is securely secured in a vice. The rough tap and hole are lubricated with machine oil. After this, install the tap strictly perpendicular to the surface of the part and, pressing along its axis, rotate the knob by the handles.

After cutting one or two threads, make a quarter turn in the opposite direction. This promotes chip crushing and removal and prevents tool jamming. The work continues, carrying out alternating rotation: ½ turn forward, ¼ turn back. In this case, it is necessary to ensure that there is no skew of the tap. You should also not apply excessive force to it. To prevent jamming, the cutting tool is periodically removed and the hole is cleared of chips.

After cutting the internal thread to the required depth, a finishing tap is installed in the hole. When it goes in the given direction, a crank is put on it and work continues. Add lubricant periodically.

The thread is checked using a plug gauge or bolt. It should screw in effortlessly and not wobble. If necessary, make an additional pass with a finishing tap.

What is a tap? Design types and how to use them

The difference between die taps and nut taps is that the former has a large intake cone and its purpose is to cut threads in one pass in the dies. Well, the last type, the master type, is usually used to clean the threads in dies after it has been cut with a die tap, and for a similar process with threads in working dies. The grooves of the master taps are made with a spiral to the right.

Fluteless swords differ from conventional machine tools, as the name implies, by the complete absence of longitudinal grooves, and the receiving cone on them is much shorter. At the tip of the threaded part there is a pair of small grooves, with the axis inclined towards the center of the tool. Grooveless taps are an order of magnitude stronger than others, rarely break, and do not produce defects. Since they have a longer thread, they can be re-sharpened many times, so they have a longer service life.

The main advantage of fluteless taps is undoubtedly their high productivity during thread cutting, especially considering their use in through and blind holes, and not just in one. Combined taps are represented by two parts and a neck separating them, and they are divided into grooveless, two-stage and drill-tapping taps. Using them saves a lot of time, because here you need to use only one tool, and not a whole set.

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:

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

The thread is checked with a nut or ring gauge. You can buy nuts for your thread here → https://rus-metiz.com/categories/gaiki (RusMetiz).

Tapping internal threads

Using a tap, cut the internal thread in the pre-drilled hole. The hole should be smaller by approximately the thread size (the thread size is indicated on the tap). Approximately as in the table:

Hole diameter for internal thread with tap

It is worth remembering that the drill will not give an absolutely accurate diameter; it will be larger by a few fractions of a mm. This is especially noticeable on diameters up to 3 mm. This should be taken into account and take a drill less than a tenth of a mm.

Just like with dies, there is a tap holder.

There are rough and finishing taps. Sometimes they cut first with a rough tap, then with a finishing tap, but mostly they use finishing taps straight away.

Manual cutting of internal threads with a tap (video)

The process is almost identical to thread cutting with a die. The tap is attached to the holder and installed perpendicular to the hole. The part with the hole must be securely fastened.

The tap and hole are lubricated and this is done periodically, after several turns. Just like with a die, you need to make 1-2 turns and 0.5 turns back to remove chips.

To check the accuracy of thread cutting, use a square, checking the verticality of the tap after several turns.

Application of the tap

Before you start threading, you need to determine the diameter of the preparation hole and drill it. To facilitate this task, a corresponding GOST was developed, which contains tables that allow you to accurately determine the diameter of the threaded hole. This information makes it easy to select the drill size.

Read also: The steamer in the iron does not work

To cut metric threads on the inner walls of a hole made with a drill, a tap is used - a screw-shaped tool with cutting grooves, made in the form of a rod, which can have a cylindrical or conical shape. On its side surface there are special grooves located along its axis and dividing the working part into separate segments, which are called combs. The sharp edges of the combs are precisely the working surfaces of the tap.

Tap: design and parameters

In order for the turns of the internal thread to be clean and neat, and for its geometric parameters to correspond to the required values, it must be cut gradually, by gradually removing thin layers of metal from the surface being treated. That is why for this purpose they use either taps, the working part of which is divided along the length into sections with different geometric parameters, or sets of such tools. Single taps, the working part of which has the same geometric parameters along its entire length, are needed in cases where it is necessary to restore the parameters of an existing thread.

The minimum set with which you can sufficiently perform machining of threaded holes is a set consisting of two taps - rough and finishing. The first one cuts a thin layer of metal from the walls of the hole for cutting metric threads and forms a shallow groove on them, the second one not only deepens the formed groove, but also cleans it.

Types of thread taps and their differences

Minimum set of taps

Combination two-pass taps or sets consisting of two tools are used for tapping small diameter holes (up to 3 mm). To machine holes for larger metric threads, you must use a combination three-pass tool or a set of three taps.

To manipulate the tap, a special device is used - a wrench. The main parameter of such devices, which can have different designs, is the size of the mounting hole, which must exactly match the size of the tool shank.

Some types of tap drivers

When using a set of three taps that differ both in their design and geometric parameters, the sequence of their use must be strictly observed. They can be distinguished from each other both by special marks applied to the shanks and by design features.

1. The tap, with which the hole for cutting metric threads is processed first, has the smallest diameter among all the tools in the set and cutting teeth, the upper part of which is heavily cut off.
2. The second tap has a shorter fence and longer combs. Its working diameter is intermediate between the diameters of the other tools in the set.
3. The third tap, with which the hole for cutting metric threads is processed last, is characterized by full ridges of cutting teeth and a diameter that must exactly match the size of the thread being formed.

Set of three taps

Taps are used primarily for cutting metric threads. Much less often than metric ones, taps designed for processing the internal walls of pipes are used. In accordance with their purpose, they are called pipe, and they can be distinguished by the letter G present in their markings.

DIY thread cutting on a metal pipe

When installing metal pipes for water supply or heating, they have to be threaded. The threaded connection of pipes is quite reliable and can withstand significant pressure (if done correctly), so let's look at how to cut threads on metal. pipe with your own hands.

First of all, we cut off the required section using a grinder or a hacksaw, making sure to control the evenness of the cut so that one part of the pipe is not larger than the other - the cut must be perpendicular to the walls of the pipe.

The pipe must be cleaned of rust, old paint, etc., if there is anything on it. Next, we cut a chamfer from the pipe (internal or external, depending on what thread you are cutting) for easier movement of the cutting tool. The chamfer can be cut with a grinder with a metal disc (→ how to work with a grinder) or with a flap disk or file.

Beveled metal pipes

Cutting external threads on a pipe using a die (die)

Everything is the same as with the rods described above, but now with a larger diameter, which most likely will require some practice and you should practice or be extremely careful the first time. Also, to obtain high-quality threads and subsequent good pipe connections, you need to work first with a rough die, then with a finishing die (such kits are sold).

The choice of die metal is also important. To work with hard alloys, you should use the appropriate dies made of certain alloys; please check this when purchasing.

But, a die is not such a good and powerful tool for cutting threads on pipes with your own hands; it is much more convenient to use clamps.

The die holder is practically the same die holder, only with a guide for smooth movement and thread cutting. The clamp is placed on the pipe of this particular guide.

We put on and attach the clamp to the pipe, screwing it in a little by hand, then you need to use either a special tool - a ratchet, which is convenient for twisting the clamp, but for household needs a large adjustable wrench or gas wrench is also suitable.

One part of the pipe must, of course, be fixed in a vice. If the pipe is cut locally, then make sure that it is not torn out somewhere due to the force applied to the clamp. The pipe can be fixed using a second gas wrench, but it is better for a second person to do this, because cutting threads with one hand is problematic.

What is a clamp and how to use it (video)

Cutting internal threads on a pipe with a tap

Sometimes you have to cut into meth. pipes and internal threads. This is done in the same way using a tap, only with a larger diameter.

To cut a good thread, you should use at least 2 taps - roughing and finishing. It is important to select the correct tap for the pipe diameter. So, the internal diameter of the pipe should be larger by the length of the tap turn (more precisely, by the thickness of the cut), this is indicated on the tap itself.

Cutting is done first with one tap, then with a second. The main thing is to strictly observe the perpendicularity of the tap stroke and control it. That's all, good luck with your threading!

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How to make a carving

The threaded connection includes 2 components:

1. Internal thread
2. External thread

A separate tool is used to produce each type of threaded surface. Internal threads are created using taps . The tap is used in conjunction with the driver. The external thread is created with a die , which in turn is installed in the die holder.

How to cut a thread with a tap.

Let's get acquainted with the process of cutting threads with taps and dies

It is difficult to imagine a mechanical working tool or functional part that would not work through the use of threaded connections. Cars, hand tools, household appliances, plumbing - this is just a small list of equipment that would not be able to function without modern threads.

Set of dies for thread cutting

It is not surprising that so often a person has to sharpen the threads on parts himself. Fortunately, this is quite easy to do. In your work you will need a small set of basic tools, taps and dies.

So how to do thread cutting correctly? Let's figure it out now.

Classification of leroks

Today, the industry produces a large variety of different dies for cutting screw connections. It is clear that they all differ in many ways. In addition to such an obvious difference as size, there are a number of other characteristics on the basis of which classification can be made:

• Form;
• Housing design;
• Thread cutting method.

There are, of course, other differences, but the above are the most obvious.

The following types can be distinguished by shape:

• Tubular;
• In the form of hexagons;
• In the form of a square;
• Round.

Dies for cutting metric and imperial threads

By design the following are distinguished:

• Solid;
• Split;
• Sliding.

According to the method of cutting threads, they are divided into the following types:

• For round threads. Manufactured according to GOST 13536-68;
• For cylindrical. Manufactured according to GOST 9740-71;
• For conical. Manufactured according to GOST 6211-81;
• For inch, the regulatory standard is GOST 61111-52, and for metric - GOST 9150-81.

Die holder

Round-shaped materials are most widespread. They allow you to make carvings in just one pass. For example, sliding dies for cutting threads of other shapes can guarantee quality only after three or four passes. However, they also have a drawback. For example, their use is recommended only when the requirements for threads on pipes or other objects are no higher than the second accuracy class.

Round dies (GOST 13536-68) allow you to produce threads of fine and coarse pitch, both in the metric and inch systems.

When working, it is important to take into account that the diameter of the chip holes and the dimensions of the thread itself are directly affected by the outer diameter of the die for cutting threads

Tool selection

Let us note in advance that threads can be cut in different ways. You can work either manually or by machine. In the first case, as we noted above, you need to have a set of tools with you for creating threads, in the second, the work is carried out on a lathe.

Manual threading is recommended if your task is to machine only a few parts. For example, when assembling plumbing equipment, creating household pipelines, etc.

Processing parts on a lathe involves performing large-scale tasks. A person with experience with this type of equipment is able to cut threads on an industrial scale, up to a hundred parts per hour, and sometimes more. However, you are unlikely to need such performance.

Most often, a set of hand tools covers all the household needs of home craftsmen. With their help, you will also be able to cut threads correctly and efficiently, but it will only take more time and effort.

The set of equipment mentioned above is mainly represented by taps and dies, as well as various additional parts.

Features of taps

Taps are cone-shaped or cylindrical parts that are designed for cutting internal threads. In particular, they are used to make threads on pipes, nuts, small washers, various kinds of clamps and even flanges.

The taps are quite convenient to use. They consist of a working and a rear part. The working part has a unique shape and diameter. On its edges there are special incisors or teeth with a certain pitch. The teeth, when rotated, cut the metal in parallel with the removal of chips.

The back side is made in a certain shape, which makes it easier to fix the tap on the working tool.

A variety of taps for household use

Taps with the ability to cut threads without forming chips are also used, but much less often, because they are more expensive.

Roughers make the first pass, remove most of the chips and form rough grooves for the threads. This is not a full carving yet, but the preparation has already been completed.

Semi-draft models are extremely rare. They are intended for finishing rough grooves, cleaning them and forming a workpiece for a clean thread. Semi-rough taps are used primarily in the manufacture of complex parts.

The last sample, a finishing tap, forms a ready-to-use thread of precise dimensions and shape.

What is a die?

A die is a tool for creating threads on the outer surface of cylindrical workpieces. Uniform twisted grooves appear on the machined side, onto which the connecting part is screwed. Smooth threads are obtained thanks to the complex arrangement of edges located on the inside of the tool. As the tool rotates, the sharp edges create uniform turns.

The design of the die is cylindrical in shape with precise placement of cutters on the inside. The diameter varies depending on the size of the workpieces being processed. The equipment has holes that are needed to secure the knob. With its help, force is transmitted to the equipment.

Threading

Now that we've sorted out the tools themselves, let's move on to the question of how to use them correctly.

Almost anyone can cope with such tasks, but there are several details and nuances in the work that you should pay close attention to.

The standard stages of work differ little from each other, and it does not matter whether you use dies or taps. In any case, it is necessary:

1. Prepare and assemble the instrument.
2. Lubricate parts and work area.
3. Perform a rough pass.
4. Check the quality of the thread.
5. Perform a finishing pass.
6. Perform final check.

There are also nuances that we will now pay attention to.

Set of taps and dies (video)

Carving with a die

Most often, a set of dies is used when it is necessary to obtain a result in the form of a pipe thread. At least in civil engineering.

When cutting threads with a die, caution plays a major role. First, the die is selected and assembled with the die holder (popularly called a knob). Then lubricate with oil or lard, if nothing else is available.

Next it needs to be fixed. At the fixation stage, beginners very often make serious mistakes. The die is difficult to fix in the ideal position. In this case, it is necessary to start cutting using pressure, and even combining it with rotational actions.

As you understand, some skill is required here.

Mounting the part in a horizontal vice, as well as lightly turning the working edge, will greatly simplify the work. Turning is done with a file.

Then the work will go easier. The die is fixed onto the machined edge by turning it several tens of degrees in both directions. Then they press (it’s easier to work if the part is below the level of your belt, then it’s easier to concentrate the pressure from your own body) and rotate in the working direction.

Thread cutting tool set

The first 2-3 turns must be done with pressure from top to bottom, then the die is tightened on its own, and you only need to rotate the knob.

Rotation is performed with translational movements. Every few revolutions in the working direction, alternate with a reverse rotation of 0.5-1 revolutions, for better turning of the thread.

Thus performs a rough pass. The finishing pass should not cause any problems for you, since the part is already ready for processing, and the process there is identical

The nuances of working with taps

They work with taps according to the same scheme. The tool set also includes roughing and finishing taps. They also need to be fixed on the holder, only here it is not a knob that is used, but a kind of vice that comes with the kit.

The main difference when cutting threads with this tool is the need to apply forced pressure throughout the entire time.

As a result, the process becomes more labor-intensive. It is correct to remove the chips from the tap yourself from time to time. Without removal, it will quickly grind down the teeth and damage the part. It is also advisable to cool the tap.

Due to pressure, rotation and interaction with chips, it heats up quickly. Industrial oil is ideal for such tasks.

Cutting pipe threads with a clamp

Such a mechanical kit is sold in any specialized stores and is especially popular among users, since there is no need to carry out an alignment operation. This feature is included in the package.

The external structure of the clamp looks more complex, but the internal contents are so constructive that it allows you to get the job done quickly and efficiently.

The tool consists of:

Round metal frame cast from durable alloy.

Four removable cutters or blade combs. The second sample has a tremendous advantage. When moving, the first cutters make shallow grooves, and the next, higher ones, sliding along the “rough” path, cut out a full-fledged one, ready for use.

A wide holder with a guide tube that minimizes the process of distortion.

Instructions for use:

The clamp is installed in the ratchet, and a guide is installed on the edge of the workpiece.

The cutters are lubricated for smooth operation/

The work of the ratchet begins, which rotates around its axis.

How to properly cut threads with dies and taps - instructions

Often, when performing home repairs, it becomes necessary to make threads - external or internal. In order not to involve specialists in this, but to do it yourself, you need to purchase a special tool. Cutting with dies and taps does not require any special skills or abilities. It is enough to know their types and technical parameters.

A little about the features of the tool

The first step is to decide on the type of thread. It is divided into 2 main types: metric and inch. The first one with the left direction is most often used. In order not to measure the distance between the grooves, you can find out the type by the shape. A metric thread in cross-section is an equilateral triangle, and an inch thread is an isosceles one.

Which products use a certain type of thread? Fasteners use metric, while water pipes use inch. In addition, you need to take into account the following factors that influence the process of cutting connecting elements.

1. If the thread is intended to be connected to a finished part, its geometric dimensions must be appropriate.
2. When manufacturing complete fasteners, it is recommended to use the metric type.
3. The diameter of the workpiece must be different from the thread size. For the outside - to a lesser extent, for the inside - to a greater extent.

Self-cutting of threaded connections is carried out using dies and taps. They are made of high-strength steel with a standardized working fluid size.

Outdoor

The die is a nut with internal slots and external clamps for turning the tool. It can be of various shapes - round, square or hexagonal. If the work is carried out at home, you will need a vice to fix the part.

Die holder and dies

Before performing work, the main thing is to choose the correct diameter of the workpiece. It should be 0.2-0.3 mm smaller than the size of the future thread. For metric, you can use the data from the table.

The workpiece should be prepared in advance. If its cross-section is not a circle, you need to turn it. Then a conical chamfer is removed from the end part to mark the first turn of the thread.

Next you need to follow the instructions exactly:

1. Having secured the workpiece in a vice, the correctness of its location is checked.
2. Installing the die into the die holder. Its surface must be in the same plane as the surface of the workpiece end.
3. The first turn is performed with little effort. It is important to make turns in the right direction.
4. Having reached the lower limit, the die must be turned in the opposite direction.

External thread cutting

One such pass will not be enough to form a thread with good geometry. It is recommended to repeat the procedure 3-4 times until the die is freely screwed onto the workpiece. To check the quality, tighten a nut of the appropriate diameter. If force is observed, you can treat the outer part of the workpiece with fine-grained sandpaper.

Internal

Taps must be used to form internal threads. They are a cylinder with an external notch. If you need to process small parts with a diameter of up to 20 mm, you can use a manual type of tap. Larger sizes require machining using a machine.

Existing threading options

Pipe threads are divided into five types, but the most popular options are conical and cylindrical. Household members often encounter such types of pipe threads. There are two methods for threading a water pipe:

• Automatic, which involves cutting threads on water supply pipes using special machines and power tools.
• Manual. For this, special hand tools are used.

If, as part of his job, a person needs to cut threads on a large number of pipes, then it is appropriate to purchase a special power tool, which will facilitate manual labor.

When the need to obtain a threaded connection is an isolated case, then manual technology is suitable for such purposes. On water pipelines, as well as pipes of heating systems, thread cutting is performed using a die.

The die is a steel disk, and its inner diameter has axial holes in different numbers, which depends on the size of the product. The edges of these holes form cutters, with the help of which thread cutting is performed. To ensure the reliability of such a tool, it is made of alloy steel or hard alloys.

Dies can have different shapes (round, square, hexagonal or prismatic), but most often disc options are used. Disc dies are intended for making threaded connections on water pipes. To make it convenient to work with the die, they are equipped with additional knobs, as well as clamps in the form of screws. Dies are also solid, split and sliding.

Solid dies for threading pipes have one significant drawback - rapid wear of the cutters. This is due to the rigidity of the product’s own design. Split or spring-loaded dies have a less rigid design, which significantly increases the service life of the product. Due to the spring-loaded mechanism, such a tool for cutting threads on pipes allows you to vary the diameter of the resulting threaded connections in the range from 0.1 to 0.3 mm. A device of this type is highly resistant to cutter wear, but is not capable of providing high accuracy.

Sliding dies are 2 working parts intended for installation in a mounting module. A die with a special fastening module forms a tool called a pipe clamp. The die is fixed in the die using a cracker and an adjusting screw. It is with the help of the adjusting screw that the thread diameter is adjusted.