Used for threading holes. How to cut an internal thread with a tap? Preparing for hand carving

The thread is one of the most convenient detachable connections, and therefore information on how to thread the thread can be useful on the farm. There is an inch and metric thread, so it happens that a seemingly suitable screw turns out to be unsuitable - the diameter is not the same and the thread pitch is different. Even the profiles of metric and inch threads are different: the apex angle in a metric thread is 60 degrees, and in an inch thread it is 55 degrees.

Any threaded connection consists of two parts, one of which has an internal thread in the hole, and the second has an external thread, on a cylindrical surface. Mostly right-handed threads are used, in which the rotation occurs clockwise, but sometimes there is also a left-handed thread with counterclockwise rotation.

For a thread, the main dimensions are the pitch - the distance between its turns) and external diameter. They are interconnected and are standard. Both internal and external threads are determined by the size of the rod diameter, that is, if the M10 thread is indicated, then this thread is metric, right-handed with a screw diameter of 10 mm and a thread pitch of 1.5 mm. Sometimes non-standardized threads are also used, for example, camera lenses are mounted on threads with a diameter of 42 mm. According to the standard, the pitch for this thread is 4.5 mm, but for an optical device this is too large a parameter, so a pitch of 1 mm is used. There are special standards for fine threads. The main thread sizes can be found in reference books and standards.

Any threads are cut using special tools and machines, and at home, you can cut the internal and external threads on fasteners with a diameter of up to ten millimeters. To do this, use a simple tool like a set of dies (for external thread) or taps (1) (for internal thread). The dies (2) are a carbide tool similar to a nut with cutting grooves.

Taps (1) are also made of carbide, this tool is similar to a screw with cutting grooves. Usually, not one tap is used, but a set of two or three tools that are used for roughing and finishing passes, and have different depths of threading. Both taps and dies, when threading, are clamped into special devices - knobs (3), the size of which must be suitable for the tool used.

Threading tools must be of high quality and sharp. Dull rusty tap good carving it will be impossible to cut, besides, there is a high probability that it will break in the first hole, and in this case more problems will be with its extraction from the workpiece. Taps made of low quality metal are suitable only for working with plastic. As for the dies, a blunt tool will cut an uneven thread, and then the nut can only be screwed with great effort.

External thread cutting

A round metal rod with a diameter equal to the diameter of the required thread is firmly clamped in a vice in a vertical position. At the end of the workpiece with a needle file or a velvet file, a chamfer is chamfered for the tool to enter and the workpiece is liberally lubricated with machine oil to facilitate threading. A suitable die is fixed in a special collar and put on the end of the workpiece. The tool is, as it were, screwed onto the workpiece, making sure that there are no distortions. With a right-handed thread, after one or one and a half turns clockwise, the die must be turned half a turn in the opposite direction. So pass the entire required length of the thread until the end of the work.

Internal thread cutting

First, a hole of the required diameter is drilled in the workpiece and a chamfer is removed for the tool to enter. The drill diameter is selected according to the reference data. Holes in the workpiece can be through (throughout the entire thickness of the part) or deaf. If a hole with a small internal thread is required, then in this case a hole longer than the thread is drilled, since the taper of the tap at the bottom must be taken into account. Allowances for drilling depth should also be taken into account.

Internal threads for greater cleanliness of the profile are formed by three taps. The first of them forms a preliminary pass, it is indicated by a risk in the upper smooth part of the tool. The second tap from the kit completes the thread formation (it is indicated by two risks), and the third tool finally forms the thread profile, it is indicated by three risks. Thus, the thread is cut gradually, and as a result a clear profile is formed. For holes with a diameter of up to three millimeters, a set of two taps is used. The threading process itself is the same as when working with dies - the repetition of reverse movements back and forth to chip chips from the tool using lubricant. If the thread is cut in blind holes, then it is advisable to periodically turn out the tap in order to completely remove metal filings from its surface. They are removed with an old toothbrush or cloth, and then you need to lubricate the tool again and continue threading until it stops.

• If the thread is accidentally wrinkled during work, then it can be restored by holding the part in a vice and driving the thread again with a tap or die.
• If it is required to further lengthen the surface of the threaded screw, then it is necessary to ensure that the die passes easily along the existing threads and does not spoil its profile.
• To prevent the thread from corrosion, it can be lubricated with technical petroleum jelly.
• If the cutting turned out to be skewed and the external thread "went" to the side, then you can cut off a piece of the rod and start the process again.
• If the tap broke in the hole, and there is no way to drill another hole nearby, you can remove the broken tool in several ways. If part of the tap remains sticking out, then its end is turned in the form of a spatula and turned out with pliers. And if part of the tap remains inside, then use nitric acid and wooden stick: a drop of acid is applied to a broken tap and wait until the acid destroys its cutting edges. Then the chip is pulled out with tweezers or knocked out on the other side of the hole (if it is through).

The question of how to cut threads with a tap arises when a pre-made hole needs to be prepared to accommodate a bolt, screw, stud, and any other type of threaded fastener. It is the tap in such situations that is the main tool that allows you to quickly and accurately cut the internal thread with the required geometric parameters.

Varieties and scopes of taps

Internal threading can be done manually or using machines of various types (drilling, turning, etc.). The working tools that perform the main work of cutting internal threads are machine-hand or machine taps.

On the different kinds taps are divided depending on a number of parameters. The following principles for classifying taps are generally accepted.

1. According to the method of bringing into rotation, machine-manual and machine taps are distinguished, with the help of which the internal thread is cut. Machine-hand taps equipped with a square shank are used in a set with a special device with two handles (this is the so-called wrench, tap holder). With the help of such a device, the tap is rotated and cuts the thread. Threading with a machine-type tap is carried out on various types of metal-cutting machines, in the chuck of which such a tool is fixed.
2. According to the method by which the internal thread is cut, universal (through) and complete taps are distinguished. The working part of the former is divided into several sections, each of which differs from the others in its geometric parameters. The section of the working part, which first begins to interact with the machined surface, performs roughing, the second - intermediate, and the third, located closer to the shank, - finishing. Threading with complete taps requires the use of several tools. So, if a set consists of three taps, then the first of them is intended for roughing, the second for intermediate, and the third for finishing. As a rule, a set of taps for cutting threads of a certain diameter includes three tools, but in some cases, when products made from specially solid material, sets of five instruments can be used.
3. According to the type of hole on the inner surface of which it is necessary to cut the thread, there are taps for through and blind holes. The tool for processing through holes is characterized by an elongated conical tip (entry), which smoothly passes into the working part. Such a design is most often used for taps of a universal type. The process of cutting internal threads in blind holes is carried out by taps, the conical tip of which is cut off and performs the function of a simple milling cutter. This design of the tap allows you to cut threads with it to the entire depth of a blind hole. For threading of this type, as a rule, a set of taps is used, which are manually rotated using a wrench.
4. According to the design of the working part, the taps can be with straight, helical or shortened chip removal grooves. It should be borne in mind that taps with grooves of various types can be used for cutting threads in products made of relatively soft materials - carbon, low alloy steel alloys, etc. If the thread needs to be cut in parts made of very hard or viscous materials (stainless, steels, etc.), then for these purposes taps are used, the cutting elements of which are arranged in a checkerboard pattern.

Taps are usually used for cutting metric threads, but there are tools that cut pipe and inch female threads. In addition, taps also differ in the shape of their working surface, which can be cylindrical or conical.

Preparing for internal threading

In order for the process of cutting an internal thread with a tap not to cause any particular difficulties and to end with a quality result, it is necessary to properly prepare for this technological operation. All methods of threading with a tap assume that a hole with the appropriate diameter has already been made in the workpiece. If the internal thread to be cut has standard size, then a special table with data according to GOST can be used to determine the diameter of the preparatory hole.

Table 1. Hole diameters for standard metric threads

In the event that the thread to be cut does not belong to the standard category, the diameter of the hole for its execution can be calculated using the universal formula. First of all, it is necessary to study the marking of the tap, in which, in without fail the type of thread being cut, its diameter and pitch, measured in millimeters (for metric), are indicated. Then, to determine the size of the cross-section of the hole to be drilled for the thread, it is enough to subtract the pitch from its diameter. For example, if a tool marked M6x0.75 is used to cut a non-standard internal thread, then the diameter of the preparatory hole is calculated as follows: 6 - 0.75 \u003d 5.25 mm.

For standard threads belonging to the inch category, there is also a table that allows you to choose the right drill with which to perform the preparatory work.

Table 2. Hole diameters for inch threads

Important for obtaining a high-quality result is the question not only of what the thread is cut with, but also of which drill to make the preparatory hole. When choosing a drill, it is necessary to pay attention to the parameters and quality of its sharpening, as well as to ensure that it rotates in the chuck of the equipment used without beating.

The sharpening angle of the cutting part is selected depending on the hardness of the material to be drilled. The higher the hardness of the material, the greater the sharpening angle of the drill should be, but this value should not exceed 140 °.

How to cut a thread correctly? First you need to pick up tools and supplies:

1. an electric drill or drilling machine capable of operating at low speeds;
2. drill, the diameter of which is calculated or selected according to reference tables;
3. a drill or countersink, with which a chamfer will be removed from the edge of the prepared hole;
4. a set of taps of the appropriate size;
5. manual holder for taps (knob);
6. bench vise (if the product in which the thread is to be cut must be fixed);
7. core;
8. hammer;
9. machine oil or other composition, which during the processing process needs to lubricate both the tap and the thread section cut by it;
10. rag.

Technology features

When cutting an internal thread with a tap, the following algorithm is used.

• In the place on the surface of the workpiece where the hole for threading will be drilled, it is necessary to form a recess for a more accurate entry of the drill using a core and a conventional hammer. The drill is fixed in the chuck of an electric drill or drilling machine, on which low revolutions of rotation of the tool are set. Before starting drilling, the cutting part of the drill must be treated with a lubricant: the lubricated tool enters the structure of the material being processed more easily and creates less friction in the processing area. You can lubricate the drill with a piece of ordinary lard or grease, and when processing viscous materials, machine oil is used for this purpose.
• If it is necessary to cut threads in small parts, they should be pre-fixed using a bench vise for this. Starting drilling, the tool fixed in the equipment chuck must be positioned strictly perpendicular to the surface of the workpiece. You should regularly lubricate the tap and make sure that it does not warp and moves strictly in the specified direction.
• At the entrance to the hole, as mentioned above, it is necessary to chamfer, the depth of which should be 0.5–1 mm (depending on the diameter of the hole). For this purpose, you can use a larger diameter drill or countersink by installing them in the chuck of drilling equipment.
• The process of cutting internal threads begins with tap # 1, which is the first to be installed in the knob. We should not forget about the lubricant, which must be applied to the tap for threading. The position of the tap relative to the hole to be machined must be set at the very beginning of work, since later, when the tool is already inside the hole, this will not work. When cutting a thread with a tap, it is necessary to adhere to the following rule: 2 turns of the tap are made in the direction of threading, 1 - against the course. When the tap is made one turn back, chips are dropped from its cutting part and the load on it is reduced. Threading with a die is performed using a similar technique.
• Having cut the thread with tap No. 1, tool No. 2 is installed in the knob, and after it - No. 3. They are processed according to the method described above. When threading with taps and dies, you need to feel when the tool starts to rotate with force. As soon as such a moment comes, you should turn the knob in the opposite direction to throw chips from the cutting part of the tool.

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Internal thread cutting

Internal thread (thread in the hole) is cut tap(fig. right). Taps are made from tool carbon, alloy or high speed steel. The tap consists of shank and working part .

shank the tap is attached to crank or machine chuck.

Working part tap is a screw with longitudinal or helical grooves for threading. As with dies, the working part of the tap has a chamfer to facilitate the entry of the tool into the hole. Helical grooves, similar to the longitudinal holes in the die, form cutting edges. The shavings come down on them.
Hand taps for cutting metric threads are produced in a set that includes two taps for threads up to 3 mm in diameter and three ( № 1 -draft , № 2 - average and № 3 - finishing ) for threads larger than 3 mm. Rough tap performs the main work and cuts up to 60% of the metal layer to be removed. Semi-finishing tap cuts up to 30% of the metal layer. Fine tap gives the thread its final shape and dimensions and cuts off the remaining 10% of the metal layer. The taps included in the kit have different diameters of the threaded part and different shape profiles. On the tail part of all taps of the set, circular risks are knocked out ( 1,2,3 ) or tap numbers are affixed, as well as thread sizes are indicated - diameter and step.

To rotate the tap when cutting threads by hand, a device is used - knob(fig. left). Gates are - unregulated(rice. a) and adjustable(rice. b).

Before proceeding with threading in the hole, mark the place of the hole with its obligatory punching. Taking into account the dimensions of the future thread according to the table (see table below), the diameter of the drill is selected.

Sometimes you can use in a simple way- to find out the diameter of the hole for the desired thread, subtract the pitch from the diameter of the thread and get the diameter of the hole.

The size of the threaded hole diameter can be calculated by the formula D=d-1.6t,
where D - hole diameter, mm;
d is the diameter of the thread being cut, mm; t - thread depth, mm.

The dimensions of the knob for fixing the tap when threading are selected depending on the diameter of the thread being cut. The approximate length of the collar can be determined by the formula
L=20D+100mm,
where D is the thread diameter.

When cutting an internal thread, the metal is squeezed out, as it were, reducing the diameter of the hole. Therefore, the diameter of the drill should be slightly larger than the inner and smaller than the outer diameter of the thread. If the hole diameter is less than required, the tap will break, and if it is larger, the thread will be incomplete, weakened.
The drilled hole is processed countersink. The use of this tool allows you to improve the quality, reduce the taper, ovality of the side surface of the hole. A countersink works in the same way as a drill.

For high-quality threading, it is important to correctly fix the part in a vice and install the first tap in the hole (fig. above a). The part is fixed so that the surface with the hole is parallel to the planes of the vise jaws, and the tap is perpendicular to the plane of the part and the jaws. Perpendicularity (90° angle) is checked with a square (Fig. b).
The thread is cut as follows (Fig. v). First, tap No. 1 is installed. Its threaded part is preliminarily lubricated with oil. Pressing the collar with the left hand to the tap, with the right hand smoothly rotate it to the right until the tap cuts 1-2 threads. At the same time, they monitor the preservation right angle, guiding the tap if necessary. After the tap has taken the correct stable position and threading has begun, the knob is taken with both hands and rotated with light pressure, intercepting every half turn. In order for the chips to break and go into the grooves of the tap, it is rotated back and forth: one and a half turns forward and half a turn back.
Having finished the passage with tap No. 1, it is turned out, tap No. 2 is inserted, threaded, the knob is installed and cut. The thread is finally finished with tap No. 3 and the thread is checked (Fig. d).
Blind threaded holes are drilled to a depth slightly greater than the length of the thread.
The quality of the thread can be checked in the workshop by screwing the appropriate bolt into the hole.

When threading, the following defects sometimes occur, which should be avoided:
1) rough or torn cut- it turns out if there is no lubrication, and also due to a skewed tap or die;
2) partial profile thread- if the diameter of the hole is greater than the norm or the diameter of the rod is less than the norm;
3) thread misalignment or tap breakage- if the diameter of the hole is less than the norm or the diameter of the rod is more than the norm.

When cutting threads in ductile and soft metals, it is necessary to periodically unscrew the tap and clean the grooves from chips.
Threads should be cut sequentially with a full set of taps.
Care must be taken to ensure that there is no distortion of the tap.
Special care must be taken when threading blind holes.
Be sure to periodically lubricate the cut thread with oil.

Despite the fact that the cutting of internal threads is not a complex technological operation, there are some features of the preparation for this procedure. So, you should accurately determine the dimensions of the preparatory hole for threading, as well as choose the right tool, for which special tables of drill diameters for threading are used. For each type of thread, you must use the appropriate tool and calculate the diameter of the preparation hole.

Varieties and parameters of thread

The parameters by which the thread is divided into different types, are:

• diameter units (metric, inch, etc.);
• number of thread entries (one-, two- or three-way);
• the shape in which the profile elements are made (triangular, rectangular, round, trapezoidal);
• the direction of the rise of the turns (right or left);
• location on the product (external or internal);
• surface shape (cylindrical or conical);
• purpose (fixing, fixing and sealing, running).

Depending on the above parameters, the following types of thread are distinguished:

• cylindrical, which is indicated by the letters MJ;
• metric and conical, denoted respectively by M and MK;
• pipe, for which the letters G and R are used;
• with a round profile, named after Edison and marked with the letter E;
• trapezoidal, designated Tr;
• round, used for the installation of sanitary fittings, - Kr;
• persistent and persistent reinforced, marked as S and S45, respectively;
• inch thread, which can also be cylindrical and conical - BSW, UTS, NPT;
• used to connect pipes installed in oil wells.

Application of the tap

Before you start threading, you need to determine the diameter of the preparatory hole and drill it. To facilitate this task, the 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 choose the size of the drill.

To cut metric threads on the inner walls of a hole made with a drill, a tap is used - a helical tool with cutting grooves, made in the form of a rod, which can have a cylindrical or conical shape. On its lateral 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.

In order for the turns of the internal thread to turn out to be clean and neat, and 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 machined. That is why, for this purpose, either taps are used, 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 perform the processing of threaded holes with sufficient quality, is a set consisting of two taps - roughing and finishing. The first cuts off a thin layer of metal from the walls of the hole for cutting metric threads and forms a shallow groove on them, the second not only deepens the formed groove, but also cleans it.

Combination two-pass taps or sets consisting of two tools are used for threading in holes with small diameters (up to 3 mm). Larger metric holes require a combination 3-pass tool or a set of 3 taps.

For manipulations with a tap, it is used special device- collar. 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.

When using a set of three taps that differ both in their design and geometric parameters, the sequence of their application should be strictly observed. You can distinguish them from each other both by special risks applied to the shanks, and by design features.

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

Taps are used primarily for threading metric threads. Much less frequently than metric taps are used for processing the inner walls of pipes. They are called pipe pipes in accordance with their purpose, and they can be distinguished by the letter G present in their marking.

Thread cutting technology

As mentioned above, before starting work, it is necessary to drill a hole, the diameter of which must exactly fit the thread of a certain size. It should be borne in mind: if the diameters of the holes intended for cutting metric threads are chosen incorrectly, this can lead not only to its poor quality, but also to breakage of the tap.

Given the fact that the tap, forming threaded grooves, not only cuts off the metal, but also pushes it through, the diameter of the drill for threading should be somewhat smaller than its nominal diameter. For example, a drill for threading M3 should have a diameter of 2.5 mm, for M4 - 3.3 mm, for M5 you should choose a drill with a diameter of 4.2 mm, for M6 thread - 5 mm, M8 - 6.7 mm, M10 - 8.5 mm, and for M12 - 10.2.

Table 1. Main hole diameters for metric threads

All diameters of drills for GOST thread are given in special tables. Such tables indicate the diameters of drills for making threads with both standard and reduced pitch, while it should be borne in mind that holes of different diameters are drilled for these purposes. In addition, if the thread is cut in products made of brittle metals(such as cast iron), the diameter of the tap drill obtained from the table must be reduced by one tenth of a millimeter.

You can familiarize yourself with the provisions of GOST governing the cutting of metric threads by downloading the document in pdf format at the link below.

The diameters of drills for metric threads can be calculated independently. From the diameter of the thread to be cut, subtract the value of its pitch. The thread pitch itself, the size of which is used when performing such calculations, can be found in special correspondence tables. In order to determine what diameter the hole must be made with a drill if a three-start tap is used for threading, the following formula must be used:

D o \u003d D m x 0.8, where:

Before- this is the diameter of the hole to be made with a drill,

D m- the diameter of the tap with which the drilled element will be processed.

Do you like to do home improvement work with your own hands, without involving various craftsmen for this? Self installation or repair not only allows you to save money on calling specialists, but also greatly increases self-esteem, right?

In the process of installing communications, it often becomes necessary to prepare threads on pipes. We have to find ways not to spoil the product.

We will show you how to cut threads with different instruments, which method is preferable to use in a given situation. The article discusses the methods available for implementation by an unskilled performer. Cutting features highlighted different types threads and equipment used for this.

The presented material is provided with visual photographic materials depicting tools for performing the work. A video with recommendations will help you to understand in detail all the intricacies of this process.

The term "pipe" has a privileged position in the field of plumbing. This term is classified with an eye to a group of standards that define the criteria for connecting various elements of plumbing structures.

Pipe threads widely used in plumbing and sewer networks, so the practice of slicing, either manually or automatically, is an activity often applicable

For example, the size of a pipe thread is indicated by a numerical value that indicates the standard bore diameter of the pipe, but not the physical diameter of the thread.

In practice, pipe threads are used:

• cylindrical ( G/BSPP),
• conical ( R/BSPT),
• round for shut-off plumbing fittings ( Cr),
• inch cylindrical (American standard NPSM),
• inch taper (American standard NPT).

A locksmith, whose main working area is the household, is recommended to take as a basis the conditional division of pipe threads into two main types:

• cylindrical ( G),
• conical ( R).

It is with these two types that the home locksmith who serves household appliances most often has to deal with. plumbing equipment performing laying or heating.

Pipe cutting is carried out in the following cases:

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Basic cutting methods

You can cut threads on pipes in one of two ways:

• automatic- on machine tools, power tools;
• manually- with help hand tool.

For living conditions, of course, manual technology is more relevant. Threading plumbing or other pipes by hand is often done with a die.

One-piece dies for pipe threads, made of strong alloy steel, are available with a body diameter of up to 65 mm. For metric threads, dies with a body diameter of up to 120 mm are produced. On the case of metric products there is a symbol "M"

A die is a simple device for threading pipes at home. The same tool is successfully used on industrial machines.

The device looks like a disc inner diameter which drilled several axial holes. The edges of these holes form several incisors (usually 8-10). The material for the dies is alloy steel or other hard alloys.

There are several types of such devices:

• whole;
• spring-loaded(cut);
• klupp(sliding).

According to the form of execution, the die is produced in the form of a circle, square, hexagon, prism. The most common are disc (round) tools. They are used for threading water pipes up to a diameter of 36 mm.

For the convenience of working with dies, use:

• simple collars with fixing screws - hand tools;
• threading chucks on lathes.

Threading (metric, conical) best quality on pipes in the mode of manual action or on machines they give solid dies.

However, this type of tool due to the rigidity of its own design has its negative sides. Blades wear out quickly.

A spring-loaded threading tool is distinguished by the presence of a cut in the area of ​​​​one of the axial holes. The presence of a cut reduces the load on the cutters, but it also reduces the degree of rigidity necessary to achieve high cut quality.

Spring-loaded (split) dies have a less rigid design, which makes it possible to cut threads on pipes and at the same time change the thread diameter in the range of 0.1-0.3 mm.

Such devices differ increased wear resistance incisors, but do not provide high precision and clean thread cutting.

Sliding dies consist of two working parts. They are designed for installation in a mounting module - klupp.

Fastening in the klupp is carried out by a mechanism consisting of a cracker and an adjusting screw. The screw adjusts the size of the diameter for threading. Usually klupp is completed with a set of dies for several different diameters.

Method # 1 - making pipe threads with dies

The process of creating a thread on a pipe with a die or a die requires the locksmith to perform some preliminary actions:

1. The surface of the pipe in the cutting area must be thoroughly cleaned.
2. The end part of the pipe should be processed with a file (make an inlet chamfer).
3. Apply lubricant to the surface to be treated to reduce resistance.

If possible, it is desirable to fix the pipe vertically, for example, in a bench vise, leaving free access to the upper part - the cutting area. It is necessary to correctly calculate the strength of the fastener so as not to deform the pipe body.

Then they take a pre-prepared wrench with a rough die (No. 1) of the desired diameter and suitable characteristics threads.

Thread cutting example water pipe with a hand wrench. A plate is inserted inside the working cylinder of the wrench and fixed with two (four) bolts located opposite each other

The tool is held horizontally - perpendicular to the end area of ​​the pipe. A rough die is put on the chamfer of the edge with an inner hole. With light pressure and successive short turns of 25-30 °, an initial incision is made.

This work should be done carefully, slowly, constantly controlling the right angle between the plate horizon and the pipe vertical.

With this technique, the first two or three threads are carefully cut. Usually, after cutting the first two or three threads, the tool firmly occupies working position. Further, the right angle can no longer be controlled.

But the technology of cutting with short (without particularly strong traction) circular motions should be maintained until the end of the cut. It is recommended to periodically add lubricant at the cutting point.

After the first pass, twist the device and then repeat one or two more times with a finishing die (No. 2).

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Method #2 - Klupp cutting technique

Klupp is a kind of the same die for threading, including on pipes. Distinctive feature kluppa - the ability to adjust the incisors.

A set of screw caps for different sizes of pipe threads. Each of these devices is equipped with screws for fastening blocks with cutters. With these screws, you can additionally change the size of the thread diameter within a small range.

There are clips for manual application, as well as similar devices with an electric drive.

Option # 1 - cut with a manual screw. Manual cutting of pipes is usually performed by a screw clamp, which is installed in a ratchet holder. Such a holder makes the work of cutting pipe threads convenient and less complicated.

Of course, depending on the conditions of the plumbing work, you can use other types of manual holders. For example, a standard locking knob with two handles.

The principle of creating a thread with a klupp is almost the same as the method of working with traditional dies:

1. Clean the working surface of the pipe, make sure there are no defects.
2. Sand the cut area to a look with a pronounced metallic sheen.
3. Process the outer working part of the end edge at an angle of 45-60º (chamfer).
4. Lubricate the prepared surface with technical petroleum jelly.
5. Fix the pipe in a mechanical vice or hold it with a gas wrench.

After these procedures cutting tool(klupp) is mounted with an internal hole on the chamfer of the pipe and, with moderate uniform pressure, they begin to rotate it with short reciprocating movements.

The so-called “ratchet” is considered a convenient tool for working with a klupp - a lever with reverse idle. With this hand tool, it is easy to cut threads on a pipe in different conditions installation or repair

If a ratchet is used as a holder, only straight-forward cutting is carried out. It should be noted the ease of use of the ratchet lock when working in cramped conditions.

For example, when it is required to process a pipe laid in close proximity to a wall.

Option # 2 - cutting with an electric screw. Along with hand tools wide application find devices with electric drive. The obvious advantage for the locksmith is a significant reduction in labor intensity.

On the other hand, not all electric cars able to carry out work in cramped conditions. In addition, when working with a hand tool, it is possible to obtain a better result.

To obtain a similar result from electric screw plugs, a wealth of experience with this tool is required.

Klupp equipment, supplemented by an electric drive. A modern efficient tool that significantly reduces the physical workload of a locksmith. True, the electric screw cap is more often used in the professional field than in everyday life.

Work with an electric screw:

1. Preparation of the pipe surface in the cut area - cleaning, chamfering, lubrication.
2. Fastening the pipe with devices capable of providing rigid fixation.
3. Fixing at the starting point of the holder of the dies with the clamp included in the kit.
4. Checking the stroke and direction of rotation of the screw.
5. Cutting the first two or three turns in the jog feed mode.

At this point, the operation of the device is stopped, the reverse rotation function is turned on, and the bug is twisted from the pipe by jogging. Be sure to periodically moisten the cut area with oil during the entire process.

Method #3 - Using Lathes

Large-scale construction and repair work, as a rule, excludes the use of hand tools. Here, turning machines are usually used for the appropriate processing of pipes.

Threading features are supported by many universal action lathes.

For the manufacture of threaded parts on pipes of different diameters, lathes are used. On a lathe, you can make threads of any configuration

With the help of machines, both internal and external pipe threads are efficiently and easily made. Mounting pneumatic (or mechanical) module lathe provides quality reliable fastening pipes, and the exact supply of the workpiece to the cutter.

To perform threading functions, apply different types incisors:

• rod,
• lamellar,
• intercalary.

The work on lathes is carried out by specialists trained in such a case, having the appropriate qualifications. Without experience and professional skills, it is not recommended to try to cut threads with your own hands on a machine.

For home craftsmen who decide to do plumbing and make carvings on metal blanks, the following tips will help in their work:

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The selection of the diameter of the drill, for the implementation of cutting, it is better to make according to the regulatory tables indicated, for example, in GOST 19257-73

metal strip, corner or profile pipe before cutting, you should prepare: clean from rust, if necessary, remove irregularities with a file

When cutting, it is very important to make the first 3-5 turns carefully and correctly. Then the tool "becomes on the move" and you can no longer worry about the correct cutting of the turns

A few words about GOST for pipe thread

When working with gaseous and liquid media, according to GOST 6111, if it is necessary to introduce detachable connections into piping schemes, it is allowed to manufacture such connections on a threaded basis.

It is possible to perform not only pipe, but also conical threads ( GOST 3662).

An example of the production of a conical pipe thread on a technological adapter. Similar techniques are often used in plumbing. In terms of performance, conical threads stand out in better side relative to other types

Despite the rare use of tapered threads in pipe connections, it is considered more convenient in terms of screwing / make-up characteristics.

It should be recalled that the taper angle of a tapered thread is directly related to parameters such as pitch and diameter. The permissible value of this angle cannot be less than 26°. The standard value for the profile tip angle on a tapered thread is 60°.

Pipe threads are different characteristic feature- they have a rounded profile top. Subject to cutting standards, the rounding value is 10% of the thread radius size.

With this cutting technology, it is possible to achieve a significant reduction in internal stresses on small area metal occupied by the threaded profile.

Tolerances set GOST 6357, along with cylindrical and conical threads, execution on pipes with metric threads is provided.

Here, the standard of the angle of inclination is 55°, which causes an increase in the number of turns in the section along the length equal to the section with a different type of thread.

The result is a connection with a higher degree of tightness, but the complexity when using such connections increases.

Metric threads and full technical layout according to standard parameters. For metric threads, the unit of measure is millimeters, while pipe threads are usually measured in inches.

The existing GOST installations also provide for the possibility of making thrust and trapezoidal threads on pipes. But in practice, these types of cutting are not used because of their low operational strength.

Used in plumbing work different ways pipe connections. The choice of method largely depends on the material of the pipeline and its “responsibility area”. Threaded joining of parts is recommended to be used in areas accessible for periodic revision.

Information on alternative ways pipe connections are presented in the articles:

1. Knowledge about the creation, operation, maintenance of threaded connections on pipes is always relevant for every person who is engaged in housekeeping, plumbing, and other engineering communications.

   Without this information, it is impossible to carry out high-quality repairs, modernize piping systems, or simply maintain the operation of household household systems.

   Have something to add, or have questions about threading pipes? Please leave comments on the publication, suggest your own methods and effective tools for creating threads. The contact form is in the bottom block.