What tools are used for thread cutting?

Features of the selection and operation of thread-cutting tools

When replacing metal pipes, situations often arise when you need to cut threads to connect individual parts of the pipeline. To make a high-quality joint, a thread-cutting tool is used. It is important to understand what types of this equipment there are and how threads can be made so that, if necessary, you can carry out repair work yourself.

Threading tool

Varieties

To choose one of the types of threading tools, you need to understand what types of threaded connections there are:

  1. Cylindrical and conical threads.
  2. Multi-start - consisting of several helical lines.
  3. Single-thread - consisting of one helical line.

Pipe threads can be made by rotating the tool to the right or left. The direction depends on the selected tool.

Power tools

You can find a large selection of electric tapping tools in hardware stores. The equipment allows you to increase the efficiency of human labor and increase productivity. Additionally, the quality of the work performed increases. Modern power tools allow you to create different types of carvings and work in hard-to-reach places. There is a special vice to secure the surfaces to be processed on the tool.

However, it is important to remember that power tools overheat quickly. Therefore, coolants must be used during operation.

Hand tools

Hand taps can be a separate accessory for power tools or attached to hand held fixtures. A hand tool consists of a handle and a body for securing the die. They can be single or symmetrical (depending on the type of thread being created). Two-piece tools can be equipped with a ratcheting mechanism for ease of use and convenience.

Ways to create a helix

To create threads, fastening threads and longitudinal grooves, you can use various devices and equipment. To make a quality connection, you need to know how to use certain devices.

Thread taps

Die

The die is used to create threads on metal pipes. The process of repair work:

  1. Places of future connection must be cleaned of dirt, paint, rust, and plaque.
  2. Remove the chamfer located at the ends of the pipe.
  3. Select a die of the required diameter and lubricate its teeth with special oil. Use it to treat the place where the carving will be.
  4. Make 6 turns of the die. In this case, you can do reverse scrolling to free the working surface from accumulating chips.
  5. Remove the die, clean it of chips, lubricate the teeth and pipe with oil. Repeat the procedure.

If the pipes are old, they must first be checked for defects. If there are cracks or holes, the product cannot be processed.

Klupp

It is a special thread-cutting tool for creating external threads. Work process:

  1. It is necessary to remove a layer of dirt, rust, and paint from working surfaces.
  2. Try to secure the workpiece in a stationary position.
  3. Apply drying oil to the work surface.
  4. Unscrew the support screws from the clamp and place it on the pipe.
  5. Attach the cutting dies and secure the structure with screws.
  6. With forward pressure, rotate the die clockwise.

Before removing the clamp, you need to squeeze out the dies.
Threading Die Review What's Inside

With a cutter

This option for making threads involves the use of turning equipment. The master secures the pipe into the spindle. After this, he fixes the cutter in the support and adjusts it. After turning on the electric motor, the workpiece begins to rotate. The master slowly brings it to the cutter and begins processing.

Tap

Taps are used to create internal threads. Use of taps:

  1. The product is fixed in a vice.
  2. The diameter of the tap is selected. It is secured in a special device - a collar.
  3. It is necessary to make two turns clockwise and half a turn in the opposite direction. This will prevent chips from getting stuck between the cutting teeth.

If a ductile metal alloy is used, you can use a screwdriver into which the tap is secured.

Before using taps, it is necessary to calculate the diameter of the future hole. There are certain tables for this that can be found on the Internet. For example, if the outer diameter of the pipe is 10 mm, then the hole should be 1 mm smaller.

tapping threads

Electric thread cutter

You need to use power tools carefully so as not to damage the surface being processed. Work process:

  1. Cut the pipe at a 90 degree angle.
  2. A support bracket is installed under the pipe.
  3. The working surface is covered with coolant.
  4. The guide lever is located.
  5. Next, you need to turn on the thread cutter and press it against the workpiece.
  6. Coolant must be supplied during operation.

To remove the cutting tool, reverse gear is engaged.
Electric threading die VIRAX Mini Phenix

Requirements for using the device

Before you start working with a power tool to create threads, you should familiarize yourself with certain requirements:

  1. When working with old pipes, you need to use a gas wrench to hold them.
  2. Before turning on the equipment, you need to clean the cutting part from old chips. The same applies to the surface being treated.
  3. Check the direction of rotation of the dies in advance.
  4. Use coolant during operation.

Before using a power tool, it is necessary to chamfer the end of the pipe.

Threading tool with gas wrench

Marriage and its reasons

There are several reasons why a workpiece may be rejected:

  1. Lack of coolant.
  2. The craftsman did not chamfer before starting to cut the thread.
  3. Using faulty equipment.
  4. Dull or damaged teeth on the cutting tool.

Do not use excessive force when working with hand tools.
Educational program: what you need to know when cutting threads by hand
A thread-cutting tool allows you to independently create reliable connections between metal pipes and other parts. Knowing the types of accessories and equipment, you can easily select a device and easily carry out repair work. If you follow the basic rules for working with a tool, you can reduce the number of defects.

Features of the selection and operation of thread-cutting tools Link to the main publication

Source: https://metalloy.ru/obrabotka/rezba/rezbonareznoj-instrument

Thread cutting: features of work on the pipeline, tools and devices

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://tokar.guru/metallicheskie-izdeliya/prisposobleniya-dlya-narezki-rezby-na-trubah-raznogo-diametra.html

What tool is used for cutting internal threads? — Metals, equipment, instructions

Often, owners of private country houses are faced with the need to create communications for gas and water supply. A pipe is used for this.

Attaching a tee to a thread on a pipe

In such communications, detachable-type connections are used, which are necessary for disassembly when repairing or replacing necessary elements. To ensure such a connection, internal threading is used.

How and what is it done?

Before you familiarize yourself in detail with the methods and tools for slicing, you should understand what is meant by this process.

Internal threading is a special mechanical processing of a workpiece in order to obtain a thread in its internal part. The workpiece can be a pipe or a cylinder. To create internal threads, a special threading tool is used - a tap.

During the cutting process, the tube or cylinder acquires protrusions-coils and special grooves, which are twisted into a spiral and alternate with each other.

To ensure that the cylinder or tube with rifling is correctly secured, the following is used:

When creating a thread, a special threading tool is used. When drawing a schematic representation of an internal thread on drawings, indicating the exact number of turns is difficult and time consuming.

Coupling with internal thread

Therefore, within the framework of the drawing, a cylinder or tube with an internal thread is depicted conditionally, regardless of the profile features:

  • located on the rod - designation using solid main lines;
  • located in the inner diameter - designation using solid thin lines, taking into account the entire length with a chamfer;
  • if a cylinder or tube with an internal thread is projected onto a plane within the drawing, then the designation of the internal diameter is made with a thin line or arc equal to ¾ of the circumference of the cylinder;
  • a solid thin line crossing the cylinder or tube in the schematic image is applied at a distance of at least 0.6 mm from the main line. A correctly executed designation is when the thin line does not exceed the thread pitch size;
  • the run is indicated by thin lines drawn at an angle of 30° relative to the center of the axis;
  • if the internal thread possessed by a cylinder or tube should be indicated on the schematic diagram as invisible, it is indicated by dashed lines oriented towards the internal diameter;
  • the length of the internal thread includes a run-out and a chamfer; as a rule, only one length parameter is indicated in the drawing, taking into account the entire profile;
  • When designating a multi-lead thread, the stroke is designated, and the pitch size and its value are indicated in parentheses.

Types of tools

Cutting can be done using various types of tools. It could be:

  1. The internal threading tool can cut square, triangular, round or trapezoidal threads correctly. The tool is distinguished by beveled edges, which, when cutting, helps to avoid friction of the side edges with the walls of the thread being created.
  2. The turning tool can also be used to cut internal pipe joints. It includes a main and secondary cutting edge. Threaded tools are easy to fasten and can be cut-off, shaped and boring.
  3. The chamfer type cutter is designed for removing internal chamfer cutting with a complex shape.
  4. The swordsman is intended for internal cutting at home. The work is performed using a special die made using hard alloy and made in the form of a nut equipped with cutting grooves

Nuances of work

A hole with a certain diameter is drilled in the workpiece and the chamfer is removed. This is necessary so that the tool can enter unhindered. You should decide in advance on the diameter of the drill.

The hole in the pipe can be through (through the entire thickness) or blind. To ensure that the profile is as clean as possible, it is recommended to use three taps.

The first will create a preliminary passage, it is indicated by the upper notch, at the top of the swordsman.

The second threading tool completes the cutting of the internal thread and is marked with two marks. The third threading tool creates the final profiles and is equipped with three notches.

Threaded pipe connection

In order to properly form a connection, you need to act gradually and as a result a clear profile will appear. In this case, the first two taps should be used for those holes whose diameter ranges from 2 to 3 mm.

In order to make the cutting correctly, you need to repeat the rotational movements - this will help the steel shavings break off from the swordsman faster.

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If cutting is carried out in a blind hole, then the tool is periodically turned in the opposite direction in order to remove metal filings from the surface.

Next, the tool is lubricated with technical oil and grease, after which cutting of the internal thread continues.

Tips for work

For a high-quality result, you should remember:

  • It is undesirable to perform cutting in those holes that are made using casting or stamping. In such cases, before performing work, the holes are pre-drilled to obtain the required internal diameter of the pipe or cylinder;
  • the cutting process begins only after the product is secured in the drilling machine using floating or reversible chucks;
  • Pre-cooling the tool with lubricant will help to cut threads correctly;
  • to ensure strict perpendicularity of the turns, it is necessary to use a drilling jig, which serves to securely fix the product;
  • if cutting is carried out in a product made of a heat-resistant alloy, then you need to use a threaded set of swordsmen, the teeth of which are staggered;
  • cutting in products made of aluminum or zinc alloy is done using machines that provide forced feed of the spindle, which ensures easy movement of the cutting tool;
  • to avoid thread defects, the blade should be installed correctly and provided with cutting fluid;
  • A tight thread is formed as a result of selecting a swordsman with the wrong dimensions; for the same reason, taper may occur. To avoid such consequences, it is necessary to work as a swordsman of the required design;
  • Cutting, in which a threaded blade is inserted into a drill press chuck or an electric drill chuck, is prohibited. In this case, adjustment of the force and angle of attack will be impossible. This will lead to tool breakage and incorrect turns.

Source: https://spb-metalloobrabotka.com/kakoy-instrument-primenyaetsya-dlya-narezaniya-vnutrenney-rezby/

Types of threading tools

Despite the fact that the history of threaded connections of parts goes back many centuries, this method of detachable fasteners continues to lead in all technical fields. The secret of popularity is the simplicity and reliability of fastening, ease of tightening adjustment, and the possibility of free disassembly and assembly. In this article we will look at the main types of threading tools and their features.

Basic classification of thread cutting tools

First of all, threading tools are divided into the following categories:

  • Machine or manual - for use exclusively on automatic machines or for cutting threads manually. Most of the tools are universal, suitable for both machine and manual cutting.
  • For cutting internal or external threads.
  • For right or left hand thread.
  • For metric, pipe and other thread standards.

Let us briefly list the main types of threading tools:

  • Thread cutters and dies.
  • Taps.
  • Round dies.
  • Thread cutters.
  • Adjustable and self-opening threading heads.

Thread cutters and dies

Thread cutters are thread-cutting tools for precise machine cutting of external and internal threads. They are equipment for lathes or machining centers. According to the design of the thread, they are divided into:

  • rod;
  • prismatic;
  • round.

They can also be single- or multi-strand (combs). Rod thread cutters with a small helix angle (no more than 4°) have rear angles on the side edges within 4-6° for preliminary cutting and 8 – 10° for final cutting. When the thread lead angle is more than 4°, the rear angles are selected differently depending on the direction of processing - for the right, the right part of the profile has the larger angle, for the left, the left.

Prismatic and round cutters have a greater number of regrinds and, accordingly, greater durability due to sharpening only on the front surface.

The prismatic cutter is placed in special holders with a constant clearance angle of 15°, the front one is taken depending on the material. A round thread-cutting tool is also mounted in a special holder at a rear angle of 10-12°, the front angle is usually zero.

The advantage of cutters is the use of replaceable plates, which reduces the cost of purchasing equipment.

Taps and dies

Taps and dies are thread-cutting tools for cutting internal and external threads, respectively. Depending on the cutting method - machine, hand, machine-hand, the tap differs in the design of the shank and length, as well as in the presence of coatings and coatings.

To increase the hardness and wear resistance of the surface, coatings such as TiN, TiAlN, TiCN, VAP and others are often used in machine tools. An important difference between a machine tap and a hand tap is the number of cutting passes.

In manual ones it is 2-3 passes, in machine ones, as a rule, one.

Depending on the hardness of the material and the type of hole, it is necessary to select the appropriate tap. For blind holes, a tap with helical flutes is required to remove chips and simplify work. It is more convenient to work with soft metals with a tap with sparse teeth. The size of the rake angle of the tap depends on the material parameters:

  • Hard steel, cast iron, bronze – rake angle from 0 to 5°.
  • Brass and medium-hard steel grades - from 8 to 10°.
  • Soft and tough steel grades – from 12 to 15°.
  • Light alloys – from 20 to 30°

Dies are hardened nuts with holes forming cutting edges used for cutting internal threads. This thread cutting tool is universal, suitable for manual and machine cutting. They are usually made from tool steel 9ХС. A more convenient and cheaper option is a die, which is the cutting nut part of a die with a universal fastening.

Taps and dies are used primarily for threads up to 2.5″ or 60 mm in diameter. For larger workpieces, thread-cutting tools are used, which allow cutting threads of any diameter and any pitch.

Thread cutters and other tools

Another type of thread-cutting tool used as equipment for milling machines is comb and disk thread cutters. Comb cutters are used for multi-thread cutting, disk cutters are used for single-thread cutting. The comb tool uses back-ground teeth with a clearance angle of 8-12°. The rake angle of the cutters is selected within 5 – 10°. Thread cutters are sharpened only on the front surface.

A popular thread-cutting tool is the thread-cutting head. Unlike a die, it is possible to replace the teeth and set the desired cutting diameter. Self-expanding heads, which are triggered when returning to their original position, are also widely used. This design solution allows you to save a significant amount of time, which is especially important in mass production.

Source: https://Trubing.ru/articles/vidy-rezbonareznogo-instrumenta

Threading: table of the most commonly used taps, types and design

Any design cannot do without a threaded connection. To obtain an internal thread, a special tool was created, called a tap.

Many types of this tool have been developed. Each performs a specific function. Some of them are intended only for use on metal-cutting machines, others can be used in domestic conditions. Special tables have been created where you can select the right tool, depending on size, design and cost.

Threading Tool Design

The cutting tap consists of several parts:

  • Shank;
  • Working part;
  • Fence element;
  • Calibrations

Using a shank, it is mounted in a machine spindle or chuck when it becomes necessary to cut an internal thread.

The cutting is done by the working part. Its appearance resembles a screw, equipped with several helical and also longitudinal grooves.

A tool with helical grooves has one important advantage. The tapping operation is performed under more favorable conditions than performing the same operation with a thread tap that has longitudinal grooves.

Almost every instrument has a front part, which is given the name “fence”. It has a conical appearance. The intake part of the tool is the first to start threading. It is continued by the calibrating part. Its functions include calibrating and cleaning the hole.

The teeth used to cut threads are called cutting feathers . Their shape resembles incisors located along the entire diameter of the tool. Each tooth is sharpened according to the technological requirements for cutting parts.

The recesses that separate the cutting feathers from each other are called grooves. They form cutting edges, and chips are removed from the cutting zone along them. The dimensions of the grooves can be seen in the corresponding standardized tables.

Small parts with a diameter of less than 20 mm are equipped with three grooves. The tool has a maximum diameter of 40 mm and is manufactured with four grooves .

Metric taps

They are measured in millimeters and refer to the metric system. The instrument is marked with the letter "M", indicating a metric measurement. For example, the M8 marking means that this tool can produce an 8 mm thread.

The size range of metric taps has a wide range. Starting from 2 mm and ending with 60 mm . That is, you can cut absolutely any thread. All data about such a tool is summarized in special tables.

Depending on the purpose, the design of the tap is selected. They are divided into several groups:

For locksmith work, only hand tools . It, in turn, is divided into several types:

  1. Nut;
  2. Spot;
  3. Uterine;
  4. Special.

Locksmith

A set of such hand taps usually consists of three tools:

  1. Chernovoy;
  2. Average;
  3. Finishing.

First, the “black” thread is cut, for which a roughing tap is used . To obtain thread accuracy, use a medium tap. The final cutting of the thread is carried out using a finishing tap and its calibration is carried out.

A special mark is made on the shank of each tap, by which the type of tap is determined. It can be digital or in the form of printed circular rings. The number of marks determines the purpose of the tap:

  1. Chernova – one ring;
  2. Finish - three rings.

In addition, the size of the thread that can be cut with this tap is marked on the tail.

Bench taps are supplied with two tools. They have a slightly longer intake cone, as well as an increased size of the first tap.

When cutting metric threads in the range of 8 - 18 millimeters, single taps are used .

For threads 6 - 24 mm, use two taps, one for roughing, the other for finishing.

Three taps cut threads in the range of 2 - 52 mm. Inch threads are also cut with several tools depending on the size. In more detail, what taps are needed can be seen in the guest table. It indicates the diameters, type of tap and the required kit.

Depending on the direction of the grooves, taps are divided into groups:

Moreover, the direction of the grooves also has different designs:

Tools with helical grooves are in most cases used for cutting very precise threaded holes.

The cutting part of the tool is divided into two types:

  1. Conical;
  2. Cylindrical

Conical

They differ in the design of the intake part, which is made slightly elongated and has an incomplete thread, which gradually becomes a calibrating part. These taps are used to cut threads in through holes.

Cylindrical

This tool cuts threads in parts where a through hole is not required.

When cutting nuts, nut devices are used without the use of machine tools . Thanks to the extended shank, the cut nuts remain on the tool.

The die parts have a large intake cone. With this tool, preliminary thread cutting is carried out in dies. The operation is performed in one pass. The threads are cleaned with master parts having grooves in the form of a right-hand spiral.

In addition to ordinary machine tools, grooveless tools are also used. They do not have longitudinal grooves. Moreover, their receiving cone is made much shorter. These tools have increased strength , they break very rarely, so the number of defective parts due to such breakage is minimized. The threaded part is long, making it possible to resharpen such tools several times.

The main advantage of grooveless parts is their high productivity. They can cut threads in any holes. For such a tool, a through or blind hole does not matter.

Universal parts are manufactured as prefabricated parts. Each part is separated by a special neck. The roughing operation is performed by the first part, preliminary cutting is carried out, and the second part is done by finishing the thread.

Working with such equipment saves time . After all, only one tool is needed to cut threads. There is no need for a whole set, the installation of which requires a lot of additional time.

Pipe taps

Inches are taken for measurements, since pipes use a different system of change.

All pipe parts are marked with the letter G, which indicates pipe threads. Here are some examples:

  • G 1/2 – half-inch thread;
  • G 3/4″ – three-quarter;
  • G1 – inch.

Half-inch pipe threads are most commonly used. This is especially true for plumbing in residential buildings, where the pipes are of such dimensions.

The pipe tap kit contains two parts. One has a sharp approach, the other is blunt.

As mentioned above, there are a lot of varieties of such instruments. Therefore, when making a choice, it is worth turning to special tables. They will tell you which tool you need to take, what diameter and what type.

Source: https://stanok.guru/metalloobrabotka/tokarnye-raboty/chem-vypolnyaetsya-narezanie-rezby-i-vybor-metchika-dlya-narezki.html

What tool is used for cutting internal threads?

Often, owners of private country houses are faced with the need to create communications for gas and water supply. A pipe is used for this.

Attaching a tee to a thread on a pipe

In such communications, detachable-type connections are used, which are necessary for disassembly when repairing or replacing necessary elements. To ensure such a connection, internal threading is used.

Taps for threading: types and features of the tool

Any tool consists of various kinds of parts, fixed together with fasteners. Despite the fact that threaded connections were well known back in the times of Ancient China, Rome and even the Mayans, taps began to be used as a thread-forming tool only towards the end of the 16th century. Until then, the internal helix of the nut was created by other means, such as a lathe.

Tool Features

Initially, a 3-4-sided rod was used, on the surface of which special teeth . The end of the workpiece was ground into a shallow cone.

The internal thread was cut using serrated bridges during the process of screwing the device into the body or nut hole.

Naturally, this device could hardly be called ideal, since the front angle of the cutting teeth was negative, and there was no rear angle at all! However, from year to year the design of the tap became more and more perfect, reaching its rational form.

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Despite the variety available, modern taps for threading have retained certain design features:

  • The calibrating part is designed to reduce the friction force, characterized by a reverse lowering equal to 0.1 millimeters and a cylindrical shape. To reduce friction, calibrating teeth are backed up from the top of the tooth at a distance of one-third of the width of the feather. Moreover, for threads with a 12-30 mm diameter, the understatement reaches about 1/10 mm;
  • Grooves for the entry of lubricating coolant and removal of formed chips. In most cases, the design provides from 2 to 6 of them;
  • The intake area is made conical, which significantly facilitates the process of cutting cutting teeth into the workpiece material. Based on the type of tap (finishing, intermediate or roughing), the angle of inclination can vary in the region of 3-20 degrees;
  • The direction of the grooves , which can be either left-handed or right-handed, or straight. The latter are used in conventional universal taps. Tools with a right-handed helical groove are more often used to create blind holes. In this case, the chips are retracted, otherwise, once under pressure, they can break the device. The left recesses of the grooves are designed to create a thread for the passage, removing chips in front of the tap, thus avoiding damage to the thread;
  • The depressions themselves can also differ: radius rear with straight front, single-radius and straight back and front.

What material is the device made of?

During operation, hand taps heat up slightly, and therefore high-carbon tool steel grades U12A and U10A are used for production.

For the manufacture of machine taps, the operation of which is characterized by increased speed, high-speed steel grades R6M5K8, R6M5K5 and R6M5 are used. At the same time, the P18 is considered the best high-speed cutter today.

High-performance machines are equipped with carbide taps. Small products are made entirely of hard alloy, medium ones are brazed, large ones are made prefabricated.

Types of thread taps

Taps can be classified according to the type of thread being cut, design features and purpose. Let's go through it in order.

According to the type of thread being cut

  • Inch conical . The reciprocal value is fixed for the step location - the number of threads (in the technical lexicon) or the number of turns per 1”. In this case, the smaller the thread pitch, the more threads there will be. The thread slope is 1° 47′ 24", and therefore it should be taken into account, in order not to break the tool, that at the end of threading the tap reaches the stop. Diameter is displayed in inches (25.4 millimeters);
  • Pipe cylindrical . The pitch is similarly determined by 1 inch threads. A subtype of inch threads, which is limited only by the number of types of standard metal pipes;
  • Pipe conical . The difference from cylindrical ones is the appearance of a slope. The thread reaches the stop. At the same time, the drilling diameter for threads is several tens smaller;
  • Metric (M). Thread pitch and dimensions are measured in millimeters. Below is a table with the main characteristics of taps with a large (main) pitch. According to GOST 8724-2002, for each standard size there are several additional steps, where 3 mm remains the maximum value that allows the driver to forcefully cut a thread.
Designation/dimensions (mm) Basic step Drilling for thread
M3 0,5 2,5
M4 0,7 3,3
M5 0,8 4,2
M6 1,0 5,0
M8 1,25 6,7
M10 1,5 8,5
M12 1,75 10,2
M14 2 12,0
M16 2 14,0
M18 2,5 15,4
M20 2,5 17,4
M22 2,5 19,4
M24 3 20,9
M27 3 23,9

By purpose

  • Nuts . The name speaks for itself - they are used to create nuts. They are always made from one tap equipped with an elongated intake cone. During operation, the taps are not unscrewed from the nut, since the finished nuts are mounted on an elongated shank made in one of two designs - curved or, as they also say, radius or straight. The radius tap has found its application on threading machines, where under their own pressure the nuts pass to the end of the tool, ending up in a special container. Straight-line is used on lathes and drilling machines. After the storage area of ​​the shank is filled, the workpiece is pulled out of the quick-release chuck, after which the finished nuts are shaken off;
  • Machine or machine-manual . They are used for mechanical thread cutting using special machines, for example, aggregate, lathe, drilling, etc. The main purpose is to cut threads inside elements. In their design they do not differ from metalworking taps, the only difference is greater durability and a smaller fence part;
  • Manual (metalwork) . Used to create threads using a crank. As a rule, they are used if you need to make a thread in a body element. To reduce effort, they are produced in sets of 2-3 devices, each of which reduces only part of the processing allowance. So the first tool in the set is considered rough, and the last one is considered finishing! You can find your bearings by looking at the special markings on the shank in the form of small dashes.

By design

  • Bells . They are used for cutting through threads with a diameter of 50 to 400 millimeters. The tap is made as a composite of several cutting elements. Spatial grooves are capable of accommodating a large amount of generated chips, the number of feathers is 16; during cutting, a cooling lubricant flows through the channels;
  • Tools with short grooves or, as they are also called, grooveless . Used for cutting threads in alloyed high-strength and low-carbon viscous steels, as well as aluminum alloys;
  • With internal coolant supply . Provide greater productivity in multi-operational and specialized machines;
  • With helical grooves . Used for cutting blind threads on machining centers;
  • Broach taps . Using them, threads with any pitch and diameter are made on a lathe in workpieces with a through hole. The part is placed on the shank of the device, which is fixed by means of a tool holder. The part itself is also clamped by the machine chuck. An automatic feed is set up, identical to the pitch of the future thread, after which the spindle rotates. After the broach leaves the workpiece, the thread will be ready;
  • With staggered tooth placement . The teeth on the calibrating part are created in sequence through one, which significantly reduces the friction force, which in turn is very important when working with viscous materials;
  • Combined . Tools are 2 in 1 type. One part is a tap, the second is a drill;
  • Stepped . The cutting area of ​​the device is divided into a pair of sections that operate according to their own shaping scheme. So, for example, one area works as a cutting area, and the second as a smoothing one, or the first creates a thread according to the general pattern, and the second - according to the profile.

Pivot table

Thus, taps for threading allow you to quickly, efficiently and easily create a thread of the desired diameter and pitch. A wide variety of models makes it possible to choose a tool option for any need.

At the end, we suggest that you familiarize yourself with the summary table containing information on the type and pitch of taps.

Pipe conical
Designation Thread pitch (threads per inch) Hole diameter, mm
Rc 1/8″ 28 8,2
Rc 1/4″ 19 11,0
Rc 3/8″ 16 14,5
Rc 1/2″ 14 18,1
Rc 3/4″ 12 23,6
Rc 1″ 11 29,6
Pipe cylindrical
Designation Thread pitch (threads per inch) Hole diameter, mm
G 1/8″ 29 8,6
G 1/4″ 19 11,5
G 3/8″ 19 15,0
G 1/2″ 14 18,7
G 5/8″ 14 20,6
G 3/4″ 13 24,2
G 7/8″ 12 27,9
G 1″ 11 30,3
Conical
Designation Thread pitch (threads per inch) Hole diameter, mm
K 1/16″ 27 6,0
K 1/8″ 27 8,3
K 1/4″ 18 10,7
K 3/8″ 18 14,3
K 1/2″ 14 17,5
K 3/4″ 14 23,0
K 1″ 11,5 28,7

Source: https://ProStrouky.ru/instrumenty-i-oborudovanie/vidy-metchikov-klassifikaciya-instrumenta-dlya-narezaniya-rezby.html

Tool for thread cutting: types of processing, use of a tap and other methods, table of device sizes

Nowadays, threaded connections are found almost everywhere: both in technical devices and in a large number of household items. The main device for making such connections is a tap. For thread cutting, it is used to quickly and effortlessly produce accurate and high-quality processing on the inner plane of the hole.

Types of thread

The design of the tool has become more sophisticated over time, and today it allows you to create clear internal threads.

The types of threads are determined by the following parameters: purpose, type of profile, pitch size, direction (right, left), measurement system (metric, inch, pipe), location on the part (internal, external), nature of the surface, number of starts.

Classification by purpose

In modern industry, there are different types of taps, differing from each other in design and functionality. According to their intended purpose, taps can be one of the following types:

  • Hand taps come in one-, two- and three-set versions. The number of the tap in the set is marked by the number of circular marks on the shank. When processing a product made of particularly hard alloys, such a set can reach five pieces. The working diameters of such tools included in the kit vary.
  • Machine taps are designed for cutting both blind and through threads. For good chip separation and for intermittent holes, use a tool with helical grooves: left - for through, right - for blind holes with right-hand threads. They are used on turning, drilling, aggregate and other machines.
  • To create threads in through holes, nut taps without reversing by threading cut nuts onto a straight or curved tool shank. Taps with this design feature are used on nut-cutting machines, where nuts are cut in a continuous cycle. As a rule, they work without forced feeding.
  • Die taps . Designed for preliminary cutting of round dies before drilling chip exit holes. The intake part is made conical along the entire profile.
  • Master taps . Designed for calibrating the threads of round dies after drilling chip holes. The intake part is conical in shape along the entire profile, the calibrating part is cylindrical.
  • Combined taps . Designed to perform multiple processing steps. Drilling a hole and tapping through holes without forced feed is feasible if the tapping tool comes into operation after the drill exits the hole.

Thread cutting in light metals is carried out using machine-hand tools defined for this purpose by GOST standards, in which the threads on the calibrating part are arranged in a checkerboard pattern. With left-hand grooves - for holes with right-hand threads, and for blind holes - right-hand threads.

In corrosion-resistant and heat-resistant types of steel, thread cutting is carried out with special tools (GOST 17927-72*).

Cutting titanium and its alloys

You should avoid cutting blind and long threads in holes to avoid breaking the working tool. The threading process becomes easier as the diameter of the hole for the threaded element increases. In difficult-to-cut materials and hardened steels, thread cutting is also performed with carbide tools. Methods of vibration cutting of a threaded element are used.

Important parameters

Depending on the required characteristics, accuracy, permissible surface roughness of the workpiece, part configuration and purpose of the threaded element, the method of manufacturing the part is chosen. This process is also significantly influenced by the manufacturability of the designs of threaded parts.

Types of tapping

Metric cutting type. The cut element of such a thread has the shape of an isosceles triangle, the entire value is measured in millimeters, such taps are marked with the letter (M). To select the right tool during cutting, a special reference table of taps is used.

Tapping table:

The inch working part of the tool has a conical shape. The diameter of such a tool is measured in inches, and the pitch is measured in the number of threads per inch.

Pipe. Cylindrical and conical taps are used for cutting threads on pipe connections.

Tips for making parts

When cutting a threaded external element, it is important to follow safety precautions. You must also follow the following recommendations:

  1. Before cutting the external threaded element of the workpiece on the rod, you need to remove the chamfer, install the die evenly without distortions, and be sure to lubricate the workpiece with oil.
  2. If the rod is bent, you can remove the defective part of the alloy and start threading again.
  3. If the hole is machined with a tap, then it must be drilled perpendicular to the plane of the part, the chamfer must be removed, and the rough tap must be lubricated with oil.
  4. When choosing taps, it is better to pay attention to the markings of the tool and opt for products made of high-speed steel. This steel is stronger and less prone to failure.
  5. If the internal thread cutting tool breaks, you must use a special tool to remove it from the workpiece.

Other types of processing

For cutting with cutters on lathes, both external and internal planes, various carbide plates or a small tool, shaped like a boring cutter, are used. Single-thread tools perform processing according to a multi-pass profile scheme. Thread cutters are prismatic, plate, rod, with mechanical fastening of carbide plates.

The tool is installed in the center of the part being cut. This processing is carried out on multi-axis or roll lathes. It is possible to use single-tooth and multi-tooth carbide inserts.

The use of replaceable carbide inserts when cutting threads on lathes makes it possible to process holes of 6 mm or more. Machine threading is suitable for a variety of materials with hardness up to 50 HRC.

Thread cutters

Another way to cut both internal and external threads is with CNC cutters that hold helical interpolation. Both whole carbide cutters and replaceable carbide inserts are used in such thread cutting tools.

There are multi-turn, single-turn, disk and comb threading cutters. When processing workpieces, preference is given to multi-turn cutters.

Their scope of application is quite extensive, since they are capable of processing material with a strength of up to 65 HRC and allow processing a wide variety of materials.

These cutters have a wide range of uses, and their diameter starts from the smallest (from 1.5 mm) and ends with the largest sizes. There are many benefits to using this tool. The same cutter can be used for holes of different diameters using the same thread pitch.

Use of abrasives

The method of processing threads with abrasive tools is significantly different from previous ones and makes it more likely to cut high-precision internal threads.

It provides a highly qualified solution for the production of a huge number of parts that have a low tolerance for error from the desired parameters. One such machine can grind a wide variety of internal threaded elements.

Elements that are manufactured by internal grinding include thread gauges and nuts for ordinary and ball screws.

Thread cutting by grinding is carried out on machines designed for these processes, which have the main features: rigidity of installation, stable temperature, accuracy of movement along the coordinate axes, the ability to perform precise movement cycles and the presence of special precision spindles with temperature control sensors.

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Knurling process

For metal processing of holes up to four gauges deep, rolling taps are used. The principle of their operation is to deform the material, while chips are not formed and there is no likelihood of chip jams. The disadvantage of this processing is the limited rigidity of the blank up to 40 HRC, since this threading method involves deformation of the material used, which must be plastic, with a low elongation coefficient.

Such a tool has great rigidity, as a result of which it is practically not subject to fracture. Rolled threads are the strongest, since the coarse alloy is compressed and becomes more uniform. One of the disadvantages of this type of taps is the requirement for the greatest torque and more power from the machine. Another limitation is that the hole must be drilled more accurately than with threading.

Rolled thread parts are not used in some industries due to the bending of the internal diameter of the thread.

How to check if it's working correctly

In order to check the correctness, and most importantly, the quality of the work done, there are special tools - calibers. Such an instrument must contain the following information:

  • Tolerance parameters;
  • Purpose PK;
  • LH code for tools with left-hand thread.

There are calibers

Before you start using these methods, you should thoroughly study the processes, choose what is suitable, and strictly follow all processing rules. You should not neglect safety precautions, only in this case the result will be high-quality and accurate.

Source: https://chebo.biz/stroyka-i-remont/metchik-kak-instrument-dlya-narezki-rezby.html

Tap

Taps are the main tool for cutting internal threads in blind and through holes manually or by machine. From the point of view of accessibility, a tap for thread cutting is a relatively simple tool, the use of which is accessible to both amateurs and professionals, allowing them to obtain a standard thread that meets GOST requirements in a regular workshop.

Tap device

This type of thread-cutting tool is a screw with straight and helical grooves necessary for cutting threads and removing chips formed in the process. The working area includes calibrating and cutting parts. For fastening the tool in hand cranks or chucks there is a square tail. The cutting process itself involves turning the tool in a pre-drilled hole (blind or through) through a reciprocating motion.

Depending on the version, the tap device allows you to cut threads in one, two or three passes. Preparation of threads in more than one pass is carried out with sets of roughing, medium and finishing tools. Sets of five tools are available for cutting holes made of particularly tough materials, such as titanium alloy.

Application

Threading taps are the main threading tool for household, semi-professional and professional use. They can be used to prepare almost all types of threads - metric, inch, trapezoidal, etc.

Main characteristics of taps:

  • Material of manufacture. The best option is alloy steels, which ensure high durability of the tool.  
  • Cutting method – for manual or machine-manual use.
  • Hole diameter is determined according to the corresponding table.
  • Parameters of the thread being cut - metric, inch, main or fine pitch, etc.

Basic rules for cutting internal threads

To properly cut a thread with a tap, you must adhere to the following recommendations:

  • Drill a hole of the required diameter. In fact, this is the main stage, because if you make a mistake, you will either get a loose thread or break the tap due to overload. For the most common, metric threads, the diameter table is given below. For a rough estimate, you need to subtract the thread pitch from the thread diameter. Drilling must be strictly perpendicular to the plane.
  • To cut manually, we perform reciprocating movements - two turns forward, one back. 
  • After passing with a rough tap, we repeat the procedure with a finishing one.
  • When cutting in a deep hole, it is necessary to periodically completely unscrew the tool and clean the grooves.
  • To tap into a blind hole, its length must be greater than the planned thread length.
  • When cutting threads in deep holes, be sure to use a lubricant - emulsion, kerosene or linseed oil.

Types of taps for threading

Depending on the cutting method, there are the following types of taps: hand-held, machine-handled and machine-operated. Manual ones are equipped with a square tail for fixation in the collar; they are available in 2 and 3 sets.

Machine-hand taps can be installed both in the driver and in the machine chuck. For cutting threads in a through hole, they are produced with six threads on the working part, for blind holes - with three.

Machine taps are designed exclusively for installation in the machine chuck and have helical and shortened flutes.

Let us briefly list some special types of taps:

  • Nuts - have a long tail for stringing nuts, which allows you to cut threads in several products without turning the tool out. Designed for machine cutting.
  • Taps for left-hand threads - designated by the letters LH, have the same pitch and diameter as a tool with a metric thread. 
  • Inch taps are a tool for cutting threads in the inch measurement system. Available in 2 or 3 sets in three accuracy classes.  
  • Pipe taps - allow you to cut pipe threads with an inch measurement system in the range from 1/8 to 2 inches. Available in manual and machine-manual versions, in two sets with sharp and blunt entry.
  • Conical taps - used to prepare the appropriate type of metric (K) and pipe (Rc) threads. They are distinguished by the presence of an elongated initial intake part with an incomplete thread, gradually turning into a full one.

Current standards

The design of machine and hand taps is regulated by GOST 3266-81. Technical specifications - GOST 3449-84. Also, each type of tool has its own standard that determines its design.

You can get visual information about the tool in the video below.

Source: https://mekkain.ru/library/metchik.html

Metal thread cutting tool

A threaded connection is one of the most popular ways of fastening various parts and elements. It is not always possible to purchase various fasteners that already have threads applied, so you need to cut them yourself. For this purpose, specialized thread cutting tools are used. With their help, it is also possible to renew previously worn or otherwise damaged threads.

There are 3 types of tools used for thread cutting:

The cutting tool differs not only in diameter, but also in the type of thread created. It can be metric or inch. Metric is used on the vast majority of fasteners.

It is used in mechanical engineering, household equipment and other areas. Inch threads are used exclusively on plumbing elements.

In some countries, metric threads are not used at all, and all fasteners are made using inch threads.

Another important difference between such a tool is the direction of the thread being created. It can be left or right. You cannot use one tool to cut threads in both directions if it is not universal.

Tap

A tap is a cylindrical tool that is designed for cutting internal threads in pipes and nuts. Its surface has protruding ribs, which, when screwed into hollow metal elements of suitable diameter, create helical grooves, cutting out chips.

As a result of screwing in, the tap creates a thread. This device is a small metal rod made of high-quality hard steel, at one end of which there is a cutting part, and at the other a shank for connecting a wrench.

There is a recess along the surface of the tap, through which the removal of cut chips is ensured. The most convenient for use are tools that have 3-5 grooves for chip removal. They clog much less and provide a clean surface without visible deformation.

After cutting the thread using a tap, the bolt or stud is screwed effortlessly over the entire surface.

Using a tap, you can cut a thread or calibrate it if it is damaged.

This tool comes in three varieties:

Hand taps are usually offered in a set of 2-3 tools of the same diameter. The former provides rough thread cutting, while the latter creates a high-quality, smooth profile that allows bolts or studs to turn easily. The order of use of the taps that come in the set is indicated by numbers on their body.

Machine tools are designed for cutting threads on machines. They have a different groove profile for faster chip removal. In this case, the shape of the shank is adjusted to fit into the chuck on the machine.

Nuts are used specifically for nuts. They are easy to recognize because they are the shortest.

Since this tool is designed for cutting threads only in nuts, which are usually small in width, it is made very short. In this regard, its length allows you to make a maximum of 12 turns.

Nut taps can also be roughed or finished. The roughing only creates the initial thread for screwing in the intake part of a longer tool.

To properly secure a hand- or nut-type tap, a special wrench is used, which is mounted on the shank. The rake angle of a tap determines its application and the metal it can work with.

The angle with an inclination of 5 to 10 degrees makes the tool convenient for processing steel. A slope of 0 to 5 degrees is intended for cast iron. Taps with sharpening from 10 to 25 degrees are used for non-ferrous metals and their alloys.

Die

The die (die) is used to create screw threads on bolts and studs. It is a round washer with a central hole, which has several protruding ribs with a sharp edge. The die cuts and calibrates external threads in one pass.

It is usually used for cutting threads on rods with a diameter of up to 52 mm. The standard thickness of the dies is from 8 to 10 turns. The angle of the cut protrusions on the die may vary. A tool with an angle of 40-60 degrees is used for through passage.

In the event that it is necessary to cut the thread close to the stop, a die with an angle of 90 degrees is used.

In order to obtain a high-quality cut thread, it is necessary that the diameter of the rod that will be processed be 0.3-0.4 mm larger than the internal size of the die. Also, when using this tool, it is worth considering that chamfering on the edge is required. In order to hold the die, special cranks are used.

The die can be solid or cut. The solid one has protruding teeth for cutting into the metal over the entire surface. Using such a tool requires serious effort. Much more popular are cut dies, which have separated working parts, which reduces the contact area. This makes it easier to remove chips and reduces friction.

The die can be used for cutting threads on the right or left side. There is also a universal tool that works equally well in both directions. It is designated by the marking LN .

Features of using a thread cutting tool

In order to obtain a high-quality thread with a smooth surface, the workpiece with which the work is being done must be secured in a vice. If this is not possible, for example when re-threading a water pipe that is already installed, it should be held with a pipe wrench.

In order to get a high-quality result, it is also important to choose the correct diameter of the thread cutting tool. If a tap is used, it should be 0.2-0.3 mm larger than the hole into which it is screwed.

If a die or die is used, then, on the contrary, the rod should be larger, by about 0.3-0.4 mm.

When using a die or tap, it is worth making several turns without using a lubricant. This will allow the teeth to cut firmly into the metal at the correct angle. If you immediately try to cut a thread on a slippery surface, misalignment may occur.

As a lubricant, you can change machine oil, grease, diesel fuel and even lard.

When working with aluminum, it is recommended to use kerosene as a lubricant. For very hard steels, the hardness of which is almost equal to the tool used, it is worth using drying oil.

When using thread cutting tools you need to do it correctly

After completing several turns, it is necessary to reverse the process. This will effectively remove the resulting chips and improve the surface of the formed protrusions.

In this case, the previously applied lubricant should be periodically renewed. If there is no machine oil, grease or lard, as a last resort, you can use very soapy water.

It is significantly inferior in viscosity, but is quite capable of improving the passage of the tool.

If you are cutting an internal thread, you should pay attention to the fact that first you take a tap that has an incomplete thread. It can be recognized by its tapered tip and the marking “1”.

It makes shallow cuts, which can hardly be called full-fledged carving. After this, a more even tap is used, on which a marking in the form of the number “2” is applied.

As it passes, it deepens the existing groove and makes it suitable for screwing in bolts and screws.

Some sets have a tool marked “3”. It allows you to prepare a threaded connection with even better quality, bringing it to perfection. When changing taps, it is worth considering that subsequent addition of lubricant is a prerequisite. Its absence can lead to early wear of the tool.

After threading tools are removed from the treated surface, they should be wiped with a dry cloth. This is especially important if soapy water was used as a lubricant. The same goes for lard oil. These substances are quite sticky, so they promote the adhesion of dust and dirt, which will subsequently lead to clogging of the thread and its sticking when screwed in.

Related topics:

Source: https://steelfactoryrus.com/instrument-dlya-narezki-rezby-po-metallu/

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