How to cut threads correctly

How to cut a thread with a tap

Perhaps the most reliable means of connection is a threaded connection. When something breaks, the first thought that comes to mind is to secure the broken part with a bolt. In addition to the durability and strength of the threaded connection, it has the property of being removable, which often plays a decisive role when choosing this type of connection.

So, before we figure out how to cut a thread with a tap, let's figure out the types of threads.

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Types of helix

A thread is a helical surface applied to bodies of rotation, such as a cylinder, as is the case with a bolt. There are two types of thread:

• right: the helix rises counterclockwise;
• left: the helix rises clockwise.

Thus, the name of the thread corresponds to the direction of twisting. It should be noted that in addition to the direction of twisting, threads are divided into the following two types:

• internal: used in holes;
• external: used on rods.

Also, each thread is characterized by the following parameters:

• profile;
• profile angle;
• step(P);
• outer and inner diameters (d2 and d1);
• thread depth (t).

Figure 1 – Diagram of the general appearance of the thread

In everyday life, right-handed rectangular and thrust threads, shown in the figure below, are most often used.

Figure 2 – Scheme of rectangular and thrust threads

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Thread cutting tool

Since we are faced with the task of cutting the thread ourselves at home, we will use a hand tap for the work.

Figure 3 – Hand tap for internal threading

The working part of the tap is directly used for cutting threads. It is a structure of two elements: intake and calibrating parts. The intake part is made in the form of a cone and performs the main work of cutting threads, while the calibrating part cleans the thread and guides the tap.

Figure 4 – Design of a hand tap

Dies are used to cut external threads.

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Internal thread cutting

The first step in how to tap a thread is to drill the hole. This stage is essentially the most important, because if you make a mistake with the choice of diameter, the bolt will either dangle, or the tap may simply break from overload.

The diameter of the holes is best selected from tables, but a rough estimate can be made: the diameter of the hole should be equal to the difference between the diameter of the thread and its pitch.

For example, with an outer diameter of 20 mm and a pitch of 1 mm, it is necessary to drill a hole with a diameter of 19 mm.

Attention! When drilling, make sure that the hole is strictly perpendicular to the plane. Any deviations can lead to marriage.

Having drilled a hole with a drill of a suitable diameter, we proceed directly to cutting the thread with a tap. To fix the tap, it is recommended to use the “wrench” shown in the figure below. If there is no wrench, use a regular adjustable wrench.

Figure 5 – Tap driver

Figure 6 – Drivers for taps and round dies

We fix the part in a vice, add a little lubricant to the hole. Next, to cut the thread with a tap manually, we perform reciprocating movements: two turns clockwise, one or half a turn back. Turning in the opposite direction is necessary to remove chips generated when cutting threads. Having passed the hole with a rough tap, we perform the steps described above with a second tap.

It is worth noting that situations often arise when it is necessary to make a thread in a fairly thin plate of soft metal, about 3-4 mm thick. In this case, you can mechanize the process using a screwdriver or drill. In this case, instead of attaching the tap to the driver, we clamp it into the screwdriver.

Rules for cutting internal threads using a tap:

1. If the hole in which the thread is being cut is deep enough, then you should periodically turn the tap out of the hole. Following this rule is necessary to clean the grooves, otherwise the tap can easily become warped. This applies more to soft metals such as copper and aluminum.

2. Use all the taps from the set in sequence: first rough, then medium and finally finishing. Otherwise, the thread may turn out to be of poor quality, and the taps may burst due to fragility.

Figure 6 – Set of taps

3. If it is necessary to cut a thread in a blind hole, the depth of the hole should be slightly greater than the planned length of the thread.

4. When machining deep holes, lubrication plays an important role. Experts recommend using emulsion, kerosene or linseed oil rather than machine oil.

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Table of drill diameters for holes for cutting metric threads (GOST 19257-73)

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We bring to your attention a video that shows how to properly cut a thread with a tap.

And another video about how to cut an external thread on a rod.

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Source: http://vse-postroim-sami.ru/materials/metal/1698_kak-narezat-rezbu-metchikom/

How to cut a thread by hand

In complex parts and elements of mechanisms, there are fastenings using a bolt and nut. Additional space is required for such communication. There are situations when the thickness of the parts is not enough for a through hole. In such situations, a screw connection is used. But to tighten the screw you need a thread, this is done using a thread tap.

The design of the device consists of a metal rod, which includes a shank and a working area. It is the shank that makes the thread itself. It has the shape of a cone with jagged edges. To prevent the groove from becoming clogged with chips when making holes, there are grooves on the shank.

Classification of taps by type of design

Depending on the task and type of hole, one or another type of tap may be required. There are several versions of this instrument, differing not only in purpose, but also in shape.

Passage

The thread on such a tool is applied in one gauge. The shank has points that perform both marking and cutting. The tool is ideal for working with soft metals; when in contact with hard materials, more pressure will be required.

Complete

When cutting threads with such a tap, 2-3 nozzles of the same caliber are required. When working with hard metals, up to five different attachments are used. The carving is not applied immediately, but in stages. The first step is to manually lay a track using a marking attachment, after which a deeper thread is cut along it. The last stage is the final pass along the track; it makes the edges perfectly even.

This method of applying threads is the most time-consuming and labor-intensive, but the risk of damage to parts is minimal.

Classification by purpose

There are different types of taps depending on the work for which they are intended. There are the following types of this tool:

• Machine-manual. The shank has a shortened shape, and square serifs are located along its length. The tool is used in electric drills and hand tools. When cutting by hand, use a special holder for the tap.
• Machine. The length of the shank has been increased. Used for fixing in power tools.

In some cases, it is possible to use the tool for purposes other than its intended purpose.

Classification by hole type

Different taps can make holes of different shapes. There are tools for:

• Through holes. The inlet area of ​​the nozzle is increased in length and practically merges with the working part. To apply cutting with such a tap, an electric drive is used.
• Blind holes. The entrance area has a shape similar to a cutter. Thanks to this, threads can be applied to the entire depth of the hole. Care must be taken when inserting the tap as it may crack. When working with such a tool, manual cutting is most often used.

Classification by part type

Depending on the metal on which cutting is needed, taps with different tooth shapes (serifs) are used. They are: straight, with grooves of shorter length and screw. Universal tools cannot be used on all types of metals.

Table of taps and drills

In order for the fastening of the future part to be tight, it is necessary to accurately match the values ​​of the through hole and the thread diameter (the values ​​are indicated in the table according to GOST). If these indicators differ, the threaded hole will be flimsy. Even with minimal loads, the cutting will be damaged. If it is too narrow, the tap will quickly break when immersed in the metal.

Note! If you do not have a tap of the required diameter, it is better to make the holes slightly smaller than larger.

Proper hand carving

Experience in cutting comes from regular work of this kind. If you have not used a tap before, use the following instructions for making threads:

• Select a drill according to the future hole (see table above). The drill for work must be sharp and even, otherwise the cutting will be flimsy. During work, the entrance area is countersunk. It is easier to make holes on a machine, this will make the screwing process easier.
• Carving. In these works, the main thing is accuracy, so there is no need to rush. Making a hole begins with a nozzle of a smaller diameter, gradually increasing the caliber. This will create a strong and smooth thread. It is also recommended to always use the finishing depth. This will ensure easy insertion of the screw. The tap size must match the screw marking. You should not use half values; in GOST there are no connections or screws with such indicators.
• Cleaning. After applying the thread, it is necessary to remove metal particles from it and clean the holes with a metal brush. Blind holes are cleaned with a brush and blown with a compressed air stream. After cleaning, screw in the screw and test the thread. The fastener should go in easily, without pressure.

Conclusion

If you make a mistake when applying a thread, you will have to redo the part or move the hole. Fasteners on incorrect threads are not permitted. For the correct application of threads with a tap, watch the video:

Source: http://obrawa.ru/metchik-dlya-narezki-rezby/

How to cut a thread with a tap correctly?

There are situations when a reliable connection cannot be made using a welding machine. In such cases, threaded connections are used. It allows you to assemble and disassemble metal structures without deformation. However, to create a connection you need to know how to properly cut a thread with a tap.

Thread taps

Types of instruments

The tool that is used to create threads is called a tap. These are cylindrical metal rods, on the edges of which there are sharp incisors located in a certain sequence. Taps are divided according to several factors:

1. Method of use. A special wrench for carrying out the work is supplied with hand tools. Tooling for machine tools is secured in the chuck thanks to a cylindrical shank.
2. According to the type of holes processed. Devices are divided into two groups. Some are used for processing through holes, others for blind holes.
3. For cutting internal, metric and pipe threads.

The shape of the taps can be either cylindrical or conical.

Design features of the tool

If you need to cut a thread, before doing this you need to understand what types of taps can be found in a hardware store:

1. Straight and screw devices are distinguished. A separate group are cylindrical rods, on which special grooves are cut to remove metal shavings from the hole.
2. Another division by design is universal, complete tools. The first option consists of taps, the working part of which is divided into three zones. They are needed for sequential coarse, medium, and finishing processing of the inside of the hole. The second option consists of sets of metal cylinders, each of which is responsible for its own type of thread cutting.

To obtain a better connection, you need to choose a set of taps. Separate devices allow you to process metal more accurately and are less vulnerable to high force. They are distinguished by reliability, durability, and high accuracy.

How to correctly determine the hole diameter?

If you take a drill of a large diameter, make a hole, and take a tap of the same diameter, problems may arise. Before you start cutting threads, you need to select the size of the equipment and the required hole diameter. For classic drill sizes, there is a special table indicating the size ratios. You can find it on the Internet.

How to cut a thread with a tap?

Tapping internal threads is a precise technological process that is carried out in a certain sequence.

Preparation

Initially, you need to prepare tools and additional devices for the work:

1. Small vice.
2. Electric drill with speed controller, metal drills.
3. Set of taps.
4. Metal brush.
5. Core with a hammer.

Thread cutting with a tap is carried out manually at low speeds of the power tool.

Tapping internal threads

Slicing process

Step-by-step thread cutting instructions:

1. Drill the hole with a core and a hammer.
2. Drill a hole with an electric drill. Hold the equipment exactly perpendicular to the surface being processed. Additionally, lubricate the drill with special oil.
3. Chamfer 1 mm in depth. To do this, use a drill of a larger diameter.
4. Secure the equipment in the collar. Perform two movements forward, one movement back. This way the metal shavings will come out of the hole and there will be no problems with cutting. Movements should be smooth.

During manual cutting, you must not apply pressure or continue to rotate the tool after it gets stuck. If it breaks, you need to drill out the tap using a drill or various metal drills. Another option for removing the fragment is to grind the area around the hole using a grinding machine. Then you need to remove it with pliers.

To create threaded connections, you need to buy the appropriate documents and learn how to work with them.
By carrying out the work carefully, without haste, you can get a reliable connection in a short period of time. How to cut a thread with a tap? Internal thread.

How to cut a thread with a tap correctly? Link to main publication

Source: https://metalloy.ru/obrabotka/rezba/narezka-metchikom

How to cut a thread with a tap and die

Threads have become the most practical detachable connection today, which is why information about threading can be useful in every household. In general, there are two types of threads - metric and inch, which is why sometimes the selected screw turns out to be unsuitable for use. That's all, because usually the thread pitch or diameter is not suitable.

Also, in addition to the above inconsistencies, if you pay attention, you will notice that even the profiles of the inch and metric threads do not match, since the angle in the inch thread is 55 degrees, and in the metric thread - 60 degrees.

Basic characteristics of thread

A threaded connection has two parts, where one part contains an internal thread in its hole, and the second has an external thread on the surface of the cylinder. As a rule, they mainly use right-hand threads, where rotation is clockwise, but occasionally left-hand threads are also used, where they rotate counterclockwise.

The size of the thread is determined by the pitch, that is, the distance between its turns, as well as the outer diameter. These measurement values ​​are standard. Both internal and external threads depend on the size of the rod diameter. So, for example, if the thread is M10, this means that the thread is metric, with a screw diameter of 10 mm, a thread pitch of 1.5 mm, right-handed.

There are also non-standardized threads, for example, there are camera lenses that are mounted on threads with a diameter of 42 mm. The standard pitch for this thread should be 4.5 mm. Such a large parameter is not suitable for an optical device; a step of 1 mm is used for it. The main thread sizes are reflected in standards and reference books.

What are the threads used for cutting?

All threads are made using certain machines and tools, and at home they cut internal and external threads with a conventional tool, which is a set of dies for making external threads, or taps for internal threads. Dies are a hard alloy tool in the form of a nut with cutting grooves.

Taps are made of hard alloy. This tool resembles a screw with cutting grooves. As a rule, several taps are taken to first make a rough pass, and then a finishing one, and also with different depths so that the cutting of threaded grooves is carried out correctly.

When cutting threads, taps and dies are secured into special devices - cranks, which must be sized to fit the tool being used.

There are a number of requirements for carving tools. These tools must be sharp and of high quality, since it will be impossible to make a good thread with a dull tap, and it can also break in the first hole. Low quality taps are used only for working with plastic. The dies must also be sharp, since a blunt tool cuts uneven threads.

How to cut external threads?

To make external threads at home, use the die described above. So how to properly cut a thread with a die at home? Here is a detailed description of this process.

A round metal rod is clamped well in a vice in a vertical position; its diameter should correspond to the diameter of the intended thread. At the end of the workpiece, a special file is used to remove the chamfer so that the tool can fit in, and the workpiece is heavily lubricated with machine oil, which will make threading easier.

The most suitable die is installed in a special driver, and is gradually put on the end of the workpiece. Screwing onto the workpiece is in progress, carefully without distortion. When making a right-hand thread, usually after one or one and a half turns in a clockwise direction, the die will need to be turned in the opposite direction by half a turn. And in this way they make carvings along the entire length.

How to cut internal threads?

To make internal threads at home, use a tap. So how to properly cut a thread with a tap? This process is as follows.

A hole of a certain diameter is drilled in the workpiece and the chamfer is removed so that the tool can fit in. The diameter of the drill is determined from the reference data. The holes in the workpiece can be through, that is, throughout the entire thickness of the part, or blind. To obtain a small-length hole with an internal thread, use a drill to make a hole of a larger length in comparison with the thread, since the existing taper of the tap in the lower part is taken into account. Allowances for drilling depth must also be taken into account.

To increase the cleanliness of the profile, internal threads are made with three taps. The first tap forms a preliminary pass, and is indicated by a mark in the upper part of the tool. The second tap completes the formation of the thread; it is marked with two marks. The third tap forms the final thread profile; it is designated three notches.

Conclusion, carving is done gradually, resulting in a clear profile. Two taps are used for holes having a diameter of up to three millimeters. The thread cutting process is similar to working with dies. There is a repetition of reverse movements, such as back and forth, so that the chips break off the tool.

When cutting threads in blind holes, it is necessary to periodically unscrew the tap in order to completely remove metal filings from its surface. Usually they are eliminated with an unnecessary toothbrush or cloth, after which the tool is lubricated again, continuing thread cutting.

Tips to make your work easier

1. If the thread is accidentally dented, it is restored by holding the part in a vice and running the thread a second time using a tap or die.
2. To further lengthen the surface of a screw with a manufactured thread, it is necessary that the die easily fits along the thread turns and does not spoil its profile.
3. To avoid corrosion, the threads are lubricated with technical petroleum jelly.
4. If the thread is skewed, cut off a piece of the rod, starting the process all over again.
5. If a tap breaks in a hole, you need to remove the broken tool by any possible means. So, if part of the tap sticks out, its end is ground into the shape of a spatula and pulled out with pliers. If part of the tap is inside, then take nitric acid and apply a drop of acid to the broken tap with a wooden stick. When the acid removes its cutting edges, the fragment is removed with tweezers.

Source: https://vseprostroiku.ru/sovety/kak-narezat-rezbu.html

How to properly cut a thread with a die by hand

A die , or popularly a lerka, is a thread-cutting tool for cutting external threads manually or by machine (on a machine) [1] [2].

Previously, the name die was used in relation to a typesetting and adjustable thread-cutting tool, preferably of larger diameters [ source not specified 426 days ].

The die has a non-separable shape and has a threaded hole with grooves; the cut thread is more accurate than that of dies. Currently, the division into dies and lerks has ceased to exist.

Dies are designed for cutting or calibrating external threads in one pass. The most common dies are for cutting threads with a diameter of up to 52 mm. The die is a hardened nut with axial holes that form cutting edges. As a rule, 3-6 chip holes are made on the dies to remove chips.

The thickness of the die is 8-10 turns. The cutting part of the die is made in the form of an internal cone. The length of the fence part is 2-3 turns. Dies are made from alloy steels (9ХС, ХВСГФ), high-speed steels (Р18, Р6М5, Р6М5К5, Р6М5К8), and more recently from hard alloys.

They are marked with the designation and degree of accuracy of the thread being cut, and the grade of steel (9ХС is not indicated).

Types of dies : solid , split and sliding (clump). Depending on the shape of the outer surface, dies are round , square , hexagonal , or prismatic .

Round dies - secured for work in gates with locking screws or secured in thread-cutting chucks. For this purpose, there are conical recesses and an angular groove on the outer cylinder of the die. The latter allows you to cut the die with a grinding wheel along the bridge and partially adjust the diameter. For round split dies, knobs with five screws are used, with the help of which the diameter of the thread being cut is adjusted.

Solid dies - due to their high rigidity, they make it possible to obtain high-quality threads (metric, conical), but have low wear resistance.

Sliding dies - installed in dies that have special guides for this purpose. The die consists of two parts, secured in the die frame with a block and a screw. This screw adjusts the diameter of the thread being cut. The die comes with a set of dies, which allows you to make threads of different sizes.

Split dies - can spring a little, changing the diameter of the thread being cut by 0.1-0.3 mm. Due to their low rigidity, split dies do not produce clean and accurate threads.

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

Set of dies for thread cutting

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

Read also: Do-it-yourself mechanical wood splitter from a walk-behind tractor

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

Tool selection

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

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

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

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

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

Features of taps

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

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

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

A variety of taps for household use

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

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

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

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

According to the type of actions performed, taps are divided into:

Note that taps, as well as dies, can cut threads of different sizes, directions and shapes. It all depends on the chosen equipment model.

Features of dies

A die is a cutting tool that is used when making external threads. The simplest example of an external thread is a bolt. While an example of an internal thread is a nut.

The dies are flat, from the outside they strongly resemble large washers or clamps for machine chucks. Only inside the die there is a cutting attachment with several rows of twisted cutters.

Tap and die, close up

Read also: Woodworking machines for home

Dies can have different shapes, types of assembly and dimensions. There are both round and square models. Some options are completely solid, others can be disassembled and the cutting attachment can be replaced.

The cutting part consists of three working zones. The two zones located at the edges consist of teeth, while the inner zone is responsible for removing chips and adjusting the direction of rotation.

It is thanks to the inner zone that the dies have a self-tightening property. That is, after several rotations on the pipe, the die is fixed.

You can then rotate it without pressure, since it will tighten in the direction of the thread formation. While the taps must be rotated with force throughout the entire process.

The types of dies are essentially the same as the types of taps. If you bought a large set of tools, you will probably receive several of these parts at once.

Threading

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

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

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

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

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

Carving with a die

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

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

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

As you understand, some skill is required here.

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

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

Thread cutting tool set

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

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

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

Read also: Scheme for connecting an electric motor through a magnetic starter

The nuances of working with taps

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

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

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

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

• How to cut a thread with a die
• How to cut threads on a pipe
• How to turn on a lathe

• - detail;
• - die;
• - knob;
• - machine oil.

Selecting a workpiece for thread cutting

The diameter of the threading rod or hole is not equal to the nominal value of the finished product. When cutting external threads, select a rod having a diameter several hundredths of a millimeter smaller than the thickness of the finished product.

This is due to the fact that when removing chips, the metal is partially squeezed out, completely filling the threaded profile of the die. For cutting internal threads, the hole is also made with a small allowance to the smaller side.

The exact diameters of workpieces for cutting metric threads are specified in GOST 19257-73.

If drills of the appropriate size are used to drill holes with an inaccurate diameter, then finding a rod suitable for cutting external threads is quite problematic. This problem can be solved by preliminary grinding of a rod of standard thickness. To do this, the product is clamped into a drill chuck and treated with sandpaper evenly along its entire length, periodically taking measurements with a caliper.

External thread cutting

Before cutting a thread on a rod, it is necessary to mark the depth of the cut and clamp it vertically in a vice. The surface should be generously lubricated with machine oil or lithol. A die of the appropriate size is installed in the holder. You should start cutting threads with the starting side of the die.

It has gradually increasing depth of cutting edges, while on the back side of the die these edges are completely reduced in one and a half turns. The die must be put on the rod and cut until increased metal resistance appears. In this case, the holder handles must be strictly perpendicular to the workpiece.

After cutting, the die must be returned a third of a turn, after which full thread cutting can begin by slowly turning the holder handles. The cut threads are lightly treated with fine sandpaper and cleaned with a fine wire brush.

Source: https://morflot.su/kak-pravilno-narezat-rezbu-plashkoj-vruchnuju/

Taps for thread cutting. Size Chart – Master Tool

Various methods are used to connect products to each other:

• welding;
• gluing;
• riveting;
• bolted;
• screw;
• hairpin.

If parts are connected with a bolt and nut, additional space is required. In addition, the thickness of the components does not always allow making a through hole.

In this case, a screw connection is used.

To screw in the screw, you need to cut the thread with a tap. The tool is a steel rod consisting of a working part and a shank and is designed for cutting internal threads. The working area has a slightly conical shape. It has teeth that consistently follow the shape of the thread. There are grooves for removing sawdust and shavings.

Specification of taps by thread cutting method

Pass-through (universal).
The thread is cut in one pass. The working part contains teeth for marking and final cutting. The device is well suited for soft metals. When working with durable material, more effort is required.

Complete.
For work, several nozzles (two or three) of the same thread size are used. When working with particularly hard metals, it is possible to use a set of five nozzles. The carving is created in several stages.

The beginning is laid with a marking tap, then a deeper cutting is carried out, and finally the final part, when the edges are finally formed.

It takes more time to complete the task, but the quality is significantly higher, and the likelihood of tool breakage is practically eliminated;

Application Specification

Machine.
Extended length shank. Designed for mounting in an electrical tool holder.

Machine - manual.
The shortened shank has flats with a square structure. Can be used both in an electric drill and manually. In the second case, a special wrench is used - a tap holder.

Specification by hole type

For through holes.
Such nozzles have an elongated approach (sharp tip of the working area), smoothly turning into the working diameter. Working with such a tap is not difficult; an electric drive can handle cutting. After the pass, the tool will simply come out on the opposite side of the workpiece.

For blind holes.
The tip of the working area is cut off like a milling cutter. This allows threads to be cut to almost the entire depth of the hole. You should work with extreme caution, since when reaching the bottom of a blind hole, a stuck tap may break. For this reason, hand cutting is practiced.

Specification by work area type

To work with various metals, the shape of the working area (teeth) can be straight, helical or with shortened grooves. The teeth themselves are arranged in one line or in a checkerboard pattern. Universal tap designs in soft and hard alloys cannot be used.

Therefore, if you want to cut threads correctly, use a tool that matches the type of metal and hole.

When cutting threads with taps and dies, it is necessary to accurately select the drill and cutting tool for the screw or stud used in the future.

Table of taps and drills for internal threads

The fact is that the through hole and thread diameter must comply with the standards. If the hole diameter is too large, the depth of the grooves will be too small and the threaded connection will be unreliable.

At the slightest load the thread will break. The other extreme is a narrow threaded hole. In this case, the tap will play the role of a drill, and its configuration is not suitable for this. There is a very high probability of tool failure.

After that, be sure to countersink and carefully cut the thread with a triple set of taps.

Popular: Metal files, and more. Classification, application.

How to cut threads by hand correctly and without wasting a tool

1. Preparing the hole. We select a drill according to the table and carefully make a hole.

   It is better to drill on a machine. It is advisable to countersink the entrance of the hole. This will make both cutting and subsequent tightening of the screw easier.

   When making a blind threaded connection, measure the length of the non-working part of the tap, multiply this value by 2, and add to the depth of the hole. No matter how prepared the tap is for such holes, it will not be possible to cut a thread to the very bottom of the hole;

2. Slicing process. There is no need to rush when working with your hands. That is why manual cutting requires complete sets. To speed up the process, you should not start immediately from the next number.

   Otherwise, the thread will turn out rough, with burrs. Also, do not neglect the last number. A thread that is not cut to the final depth promises difficulties when tightening the screw, and even jamming.

   The tap sizes are also not designed for experimentation. If you have an M5 screw, then the tap should have the same marking. There are no half-measures; these are all the tricks of Chinese garage manufacturers.

   Moreover, this thread size does not exist in technical standards.

   The tap holder should be grasped firmly by both handles and equal forces should be applied to them. The golden rule of cutting: +360 degrees, – 180 degrees.

   This means that for one full turn along the thread, half a turn is made back to chip and remove chips. Don't be fooled by the feeling that the tap moves so easily. The temptation to spin quickly at the final stage is especially great. Internal thread cutting must occur at a uniform speed and force;

3. Cleaning and checking. The last step is to remove any remaining shavings and sawdust from the threaded hole. Through holes are cleaned with metal brushes.

Deaf - first cleaned with a hard brush, then blown with compressed air.

After that, a screw is screwed into the hole and the quality of the thread is checked. Twisting should happen easily, without effort. Fixing a screw connection using a “crooked” thread is unacceptable.

If something went wrong, or what to do with a broken tap

If the work is carried out incorrectly, the tap may break. Reasons leading to breakdown:

• tool misalignment;
• hole diameter mismatch;
• cutting speed too high;
• disregard for the rule +360 degrees, -180 degrees.

If you don’t know what preliminary hole needs to be made in the metal in order to cut a thread and not break the tap, download GOST 19257-73, it’s called “Holes for cutting metric threads.”

How to unscrew a broken tap

There are actually few ways.

1. Extractor. Classic extractors for broken bolts and studs will not help here.

   It is almost impossible to drill a hole in the tap due to its exceptional hardness. A special device is required.

   Special guides are inserted into the grooves of the stuck tap, pressed with a sleeve against the rod, and the tap is unscrewed with a regular wrench;

2. Spot welding. An L-shaped steel rod is welded to the tap. After tacking, the tip can be easily unscrewed;
3. Etching with acid compounds. If the tap breaks in non-ferrous metal, you can etch it with acid. The use of hydrochloric or sulfuric acid is dangerous to health, so it is necessary to use citric or oxalic acid. The solution is poured into the hole and heating is carried out. The tap corrodes intensely, and after some time it can be removed.

And in conclusion, video information on cutting internal threads with a tap.

Table for selecting taps for thread cutting, and other secrets of manual cutting Link to main publication

Source: https://cs-important.ru/rejtingi/metchiki-dlya-narezaniya-rezby-tablitsa-razmerov.html

How to properly cut threads with taps and dies?

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

Set of dies for thread cutting

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

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

How to cut a thread by hand - Builder

A variety of tools can be used for cutting threads, among which we highlight a tap.

It is used to create a threaded surface designed to accommodate a screw, stud, bolt, or other fastener.

Relatively low cost and ease of use determined the widespread use of the hand tool in question. Let's take a closer look at how to properly cut a thread with a tap at home.

Lathes or drilling machines have been used for cutting threads for quite a long period. They are designed to rotate a workpiece or tool. In almost all cases, the working tool is a tap.

The classification of such a tool is carried out according to a number of different characteristics:

1. Depending on the method of driving them into rotation, they can be divided into machine or machine-hand taps. A special feature of the machine-manual variety of the tool is the presence of a square shank, which is suitable for a holder with two handles. Thanks to such a holder, you can rotate the tool and cut threads. As for the machine variety of the tool in question, it is installed in the chuck of various machines and can have a shank of various shapes and sizes.
2. There are universal and complete taps based on characteristics related to the specific application. The universal version has a working part, which is divided into several sections. They differ from each other in geometric shape, the first is intended for roughing, the second and subsequent ones are for bringing the surface to a suitable state. The complete version is designed for the phased use of several taps. As a rule, a set for cutting threads in ordinary metal is represented by three tools, and for processing hard alloys - five.
3. Taps are classified based on the type of hole being machined: blind or through. To work with through holes, a tool with an elongated conical tip is used, which is a continuation of the working part. Universal taps often have this type of shape. If you need to cut a thread in a blind hole, then use a tool that has a cut tip resembling a milling cutter. Due to this shape, it is possible to cut threads along the entire length of the hole.
4. Thread cutting tools are also classified according to the type of working surface. Examples include helical, straight or shortened grooves. On sale you can find a version that also has a combined surface. It is suitable for processing metals with low hardness. For hard alloys, a tool with cutting elements arranged in a checkerboard pattern is used.

As a rule, high-quality tool steel is used in the manufacture of tools. It can withstand long-term use and does not heat up during operation.

A high quality tap has a strict geometric shape and looks neat. A similar tool is often used for cutting metric threads, but there are versions for producing inch threads.

The shape of the base can be cylindrical or conical.

Preparatory stage

To ensure that the work of obtaining threads does not cause many difficulties, careful preparation should be made for such a technological operation.

All methods used related to cutting internal threads assume that a hole of the required diameter has already been obtained in advance.

You can obtain the standard thread size when creating a hole according to the correspondence table. For example, for an M10 thread, a hole with a diameter of 8.5 mm is created.

There is often a situation where it is necessary to obtain a thread of a non-standard size. In this case, the required hole diameter is calculated using a universal formula. Calculations are carried out as follows:

1. The marking of the tool used is studied. You need to pay attention to the type of thread being cut, pitch and diameter.
2. You can determine the required hole diameter when using an M5X0.75 tap as follows: 5−0.75=5.25 mm.

The easiest way to carry out the work is when you need to get a standard thread, since all the necessary information can be taken from various tables of regulatory documentation.

To get a quality hole, you need to choose the right drill. When drilling, it is recommended to use equipment that prevents runout during operation. When choosing a drill, it is worth remembering that it must have high-quality sharpening.

Experts recommend selecting the sharpening angle depending on the hardness of the material being processed.

As the hardness increases, the recommended sharpening angle also increases, but it should not exceed 140 degrees.

Required Equipment

Manual tapping is only possible with the following tools:

1. An electric drill that can operate at low speeds.
2. A high-quality drill, the diameter and sharpening angle of which is selected from table values ​​or calculated.
3. To chamfer the edges of the hole, you will need a countersink or large diameter drill.
4. One or a whole set (depending on the type) of taps of the appropriate size.
5. A hand holder that is suitable for the tool used.
6. A bench vise in which the product will be fixed. When cutting a thread, a certain layer of metal is removed, which is only possible when a lot of force is applied. If the workpiece or finished product is poorly fixed, the quality of processing will be low.
7. Core and hammer.
8. In order to simplify the task, it is recommended to use machine oil to lubricate both the tool itself and the surface being processed. If you do not use machine oil or another substance with similar properties, the process may be significantly delayed.
9. Rags.

After finding everything you need, you can begin the actual work.

Features of the technology used

carry out the work in question with your own hands at home. To do this, you need to consider the recommendations below:

1. Before creating a hole, it is recommended to make a small recess, which will ensure the correct entry of the drill. You can use a core for this. When drilling through metal, it is recommended to set the drill speed to low, which will allow you to achieve high quality processing. Before drilling, you can treat the cutting edge with a special compound, which will make it easier for the tool to enter the metal.
2. At the time of creating the hole, the drill with the drill bit must be positioned strictly perpendicular to the surface being processed. When using the tap, the cutting edge should be constantly lubricated with engine oil, and you should also ensure that the tool is positioned strictly parallel to the axis of the hole created.
3. In almost all cases, chamfering is carried out at the entrance of the hole, the size of which is 0.5-1 mm. To do this, you can use a countersink or a larger diameter drill.
4. When using a set of taps, thread cutting should begin with tool No. 1. The direction of the thread should be strictly controlled at the very beginning of the work, since in the future it will be almost impossible to change the inclination of the tool used.
5. To obtain high-quality grooves, it is recommended to make two turns along the thread and one in the opposite direction. The reverse rotation is done in order to remove chips from the cutting edge, due to which the stroke becomes smoother.
6. After using tool No. 1, the second one is installed, and after a complete passage, the third one is installed. It is worth considering that with great force it is recommended to make one or several revolutions in the opposite direction, due to which the chips are removed from the cutting zone.

It is not recommended to apply a large load to the handle by using a lever or a gas wrench.

Do not forget that the tap may burst due to high load, then removing the remaining part inside will be quite difficult.

While working, the master must feel how the tool moves: easily or with great effort. The shape of the cutting edge does not allow removal of chips from the working part at the moment of rotation along the thread.

Source: https://strojchik.ru/kak-narezat-rezbu-metchikom-vruchnuyu.html

How to properly cut threads in aluminum?

We cut the thread with a tap. The most basic and common option for fastening parts is a threaded connection. It would seem that making it yourself would not be difficult.

In fact, correct cutting of a thread with a tap requires compliance with many rules, otherwise a high-quality connection will not be possible in the future, or even the thread will not succeed at all or the tool used will become unusable.

 How to cut a thread with a tap yourself.

Tool selection

Poor quality tools mean poor quality work. Using old, dull or rusty taps or dies is fraught with the risk of them breaking during operation and poor threading on the part. In addition to tools that have been unusable for a long time, you should also avoid those that were unsuitable from the very beginning. These include all cheap options of unknown origin.

In addition to quality, their size is also important, namely the ratio of the sizes of the drill used and the hole for it. You can calculate the necessary parameters using the formula, but to facilitate this process, examples with exact ratios are given:

• metric thread M2 – drill (tap) diameter 1.6 mm;
• m.r. M2.5 – d.s. 2.2 mm;
• m.r. M3 – d.s. 2.5 mm;
• m.r. M4 – d.s. 3.3 mm;
• m.r. M5 – d.s. 4.2 mm;
• m.r. M6 – d.s. 5 mm;
• m.r. M8 – d.s. 6.7 mm;
• m.r. M10 – d.s. 8.3 mm.

Parts lubrication

This point is very important, because thanks to it the tool used will last many times longer. In addition, it reduces the likelihood of drill breakage inside the hole and reduces the temperature of the heated edges of the tap. But when choosing a lubricant, you must take into account the material of the parts on which the thread is applied:

• steel, brass – linseed oil;
• aluminum - kerosene;
• copper - turpentine;
• bronze, cast iron - without the use of coolant (cutting fluid).

It is not recommended to use mineral or machine oils as a lubricant. Their composition does not allow the surface of the tap or die to glide smoothly, so the thread will be rough.

How to Tap a Thread: Internal Threading

The main nuances have already been discussed; now you can go directly to how to cut a thread with a tap or die. The process looks like this step by step:

We clamp the workpiece in a vice.

We drill a hole for further cutting of the internal thread.

Using a drill whose diameter is several millimeters larger than the planned thread, we apply a chamfer to the edge of the hole. It is necessary for easier insertion of the tap, as well as to facilitate the process of screwing the screw into the finished product.

We insert a rough tap into the driver (a device for fastening taps and dies).

Apply lubricant to the cutting part.

Insert the tap into the hole and make three turns.

After the first three revolutions, we make one revolution in the opposite direction. Thus, we break the chips resulting from the cutting process and they will not interfere with the high-quality and even application of the thread.

If the hole in the part is through, it is necessary to make sure that the front part of the tap comes out completely from the back side. Without doing this, we risk getting an unfinished thread.

Breakage of the cutting part of the tap in a blind hole

If the end of the broken part is completely “recessed” in the hole, it will be very difficult to get it out. But if you have some patience, it’s still possible to do this.

You will need paraffin, an oblong and thin wooden stick, and nitric acid. Lubricate the workpiece with paraffin (protect it from acid).

We moisten the end of the stick with acid, insert it into the hole and lubricate the cutting edges of the metric. How to cut a thread with a tap

It is necessary to continue the procedure until the edges begin to melt. After this, the fragment is either knocked out with a hammer from the back of the part, or picked out with tweezers.

How to cut threads with a estimator: cutting external threads

Having taken the necessary part, we clamp it in a vice. We make a small chamfer on one side with a file, lubricate this side with oil, kerosene or turpentine (depending on the material).

We insert and fix the die into the die holder. We place the die to the desired end of the pipe and slowly rotate it in the direction we need with one hand, with the other hand we make sure to press the top of the die to the pipe.

When the die is firmly seated on the pipe, check that it is perpendicular to the pipe, grab the die holder with both hands and make 3-4 turns forward, and then half a turn back.

When cutting external threads, there is one caveat: during the last turns, do not rotate backwards, this will allow the nut to be firmly fixed on the pipe.

Please note that freshly cut threads should not be touched with bare hands; they may have very sharp burrs and there is a high risk of cutting.

Noteworthy information : Threading die , How to attach an anchor bolt

Source: https://varimtutru.com/kak-pravilno-narezat-rezbu-v-alyuminii/

How to properly cut a thread with a tap? — Metals, equipment, instructions

remontoni.guru > Tools and equipment > How to cut internal threads - types of taps, technology, tips

There are many ways to connect parts, but the most common and accessible is still screw (bolt) fasteners. It is this type of fastener that we will talk about. More precisely, we will look at the types of taps, the technology for cutting threads in holes for screws and bolts of different diameters.

• Types of taps
• Specification for cutting method
• Specification by hole type
• Marking of taps
• How to cut a thread with a tap - technology
• Some useful tips
• Let's sum it up

Types of taps

Taps are divided depending on the method of making the thread , as well as depending on the hole for which they are intended.

Specification for cutting method

According to the cutting method they are distinguished:

1. Go-through taps. A special feature of this tool is that it has both marking cutting teeth and teeth for finishing thread cutting. Most often, such tools are used when working with parts made of soft metals, for example, aluminum, copper, brass.
2. Complete taps. In this case we are talking about several tools for carving. The minimum set consists of three taps for different stages of cutting: the first is intended for roughing, the second for intermediate, and the third for final. Of course, doing the job with such a kit takes more time compared to using one through tap, but the quality of the turns is much higher.

Marking of taps

Taps for cutting internal metric threads are marked with the letter “M”. In this case, the letter “M” is followed by the value of the diameter of the thread being cut. In addition to the diameter, the thread pitch is also indicated on the tool.

For example, the marking M4 × 1 means that the tool can make threads in a hole with a diameter of 4 mm in increments of 1 mm. In the case of a cutting tool for left-hand threads, the tool is marked LH.

The diameter and pitch of the thread are indicated in a manner similar to that described above.

How to cut a thread with a tap - technology

Internal thread cutting looks like this:

1. The workpiece is drilled. Drilling is best done using a drilling machine, because in this case the hole is strictly perpendicular. The diameter of the drill is selected according to the table.
2. After drilling, the hole is countersinked on a machine or using an electric drill. A countersink is necessary to obtain a small cylindrical recess at the end of the hole.
3. The workpiece is fixed in a bench vice. A tap pre-lubricated with machine oil is installed in the hole to be machined. The cutting tool must be installed strictly vertically; skew in one direction or another is not allowed.
4. A crank is put on the tap, and, pressing it against the workpiece with the left hand, the right hand carefully turns it until the tap cuts into the metal and takes an even position.
5. The driver is smoothly rotated with both hands, while making two full turns, it is turned in the opposite direction, thereby breaking off the chips. This way the entire hole goes through. Remember, if you do not break off the chips, the tool may jam, and this, in turn, can lead to its breakage.
6. After cutting, the tap is unscrewed and the thread is checked. Checking is carried out using a screw or bolt of suitable diameter. Screwing in and out should occur without much effort.

For maximum clarity, we invite you to watch a short video that discusses in detail the process of cutting internal threads.

Some useful tips

• If you need to cut threads in stainless steel, it is best to use oleic acid or an emulsion based on it as a tap lubricant. You can get such an acid or emulsion from turners;
• Drilling for subsequent processing should be done with a sharp drill. If you use a dull drill, during the drilling process there is a risk of “losing” the metal, as a result of which the fastener will not be so strong;
• if it is necessary to cut a small diameter thread in an aluminum workpiece, it is best to use ethyl alcohol as a lubricant;
• If a drill of the required diameter is not available, it is better to use a drill with a smaller rather than a larger diameter for drilling.

Let's sum it up

In order to really cut a high-quality thread in a workpiece made of a particular metal, you do not need to have any special knowledge or experience. As practice shows, even a master who is far from plumbing can cope with such work.

The main advice is to avoid haste and approach all operations, including preparatory ones, responsibly . No less important is the choice of tool to complete the job - there is no need to skimp. Remember: cheap, low-quality taps often break off during operation, and removing a piece of tool from a hole is extremely problematic.

Tapping internal threads

Source: https://spb-metalloobrabotka.com/kak-pravilno-narezat-rezbu-metchikom/

How to cut internal threads - types of taps, technology, tips

remontoni.guru > Tools and equipment > How to cut internal threads - types of taps, technology, tips

There are many ways to connect parts, but the most common and accessible is still screw (bolt) fasteners. It is this type of fastener that we will talk about. More precisely, we will look at the types of taps, the technology for cutting threads in holes for screws and bolts of different diameters.

• Types of taps
• Specification for cutting method
• Specification by hole type
• Marking of taps
• How to cut a thread with a tap - technology
• Some useful tips
• Let's sum it up