Despite the widespread dominance of polypropylene pipes, metal plumbing and heating systems are still in demand.

This means that when laying steel pipelines you will need tools for processing them. One such tool is a thread cutting die. With its help, work on pipes is carried out quickly and with professional quality.

What tools are used to cut external pipe threads?

The list is not long:

Lathe.
Mechanical or electrical clamp.
Die (aka lerka).

In addition to a file, you will need a lathe or a lathe. This is not a joke: in industrial conditions, coils are actually cut using a machine. Especially if pipe threading occurs internally.

Processing on the outer surface is also possible if the workpiece is not too long. Using a die on a machine is undesirable (although it is possible); a cutter is used for cutting threads.

The advantage of a lathe: it is the only external thread cutting tool that can correctly form the conical shape of a joint. No manual threading kit can consistently increase the diameter of each subsequent turn.

This type of cutting, after tightening, creates a strong and tight joint that works on the principle of a Morse cone. The disadvantage of a lathe is obvious: not everyone has such a machine at home. Maximum mechanization is a portable electric clamp.

Even 20 years ago, when normal tools were in short supply, home mechanics actively used ordinary dies. A die for cutting threads could be borrowed for a short time, and it was taken to process pipes already laid along the walls.

The die (unlike the die) was made entirely of hardened alloy steel, and did its job properly as part of 2-3 pass-through sets: each subsequent number cuts deeper and deeper turns.

With the help of a die or a die (in common parlance - a “lerk”), only cylindrical threads are cut. It allows you to adjust the length of the joint, but does not ensure tightness without sealing materials.

Actually, what is a klupp, and how does it differ from a lerka?

The die (deck) is a monolithic structure. On the one hand, this allows you to cut threads with high precision. The other side of the coin is that the large diameter (and therefore circumference) of the pipe creates a huge load.

If you are repairing plumbing, changing the water supply system, then you need to know how to correctly cut a thread on a pipe with a die in order to screw on a faucet, coupling, and the safety of repairing your apartment, as well as the neighbors below, depends on the correct thread cutting.

I have already described the thread cutting process itself in the article "", but based on the questions received by email from readers of my blog, I decided to describe in more detail how it should be done.

In order to cut a thread, you will need the following tool:

die holder, lerka
rough thread cutting die
finishing die
grease, machine oil or a piece of lard
grinder or file

They are also called first pass and finish dies.

Why I recommend using two dies:

Firstly, it is easier to cut, and secondly, tool wear is reduced, and with the current quality, this is very important, since now you will cut 3-4 threads, and you can throw away the die.

If you are cutting a thread on a water or heating riser, or a tie-in to an apartment, be sure to make sure it is in good condition, otherwise you risk breaking the pipe!!!

1. When you cut the pipe to size, on the side where you will cut the thread, be sure to remove the chamfer, you can also slightly clean the place where the thread will be, if there is paint on the pipe, then it is better to clean it, it will be easier to cut the thread.

2. Lubricate the thread and the teeth of the die with grease or lard.

3. Take a die holder with a 1st pass die, or a thread-cutting tool for rough threads (pictured) and pressing it with your hand with force (so that the die catches on the pipe and starts cutting), begin cutting clockwise, approximately 5 turns. After about the 2nd turn, when it gets tight, turn it back half a turn, this will break off the chips, and it will be easier to cut, and turn clockwise again.

4. When you have cut the rough, take the 2nd die, again lubricate the threads, the die for finishing threads, and repeat the same steps.

And now some tips and nuances.

Do not buy taps with 3.5 turns of internal thread, even if they are thick-walled, such valves can be screwed onto fittings with brass threads; they are not suitable for water pipes or iron pipes.

Be sure to cut the first thread through the guide so that the thread does not become skewed.

If you are cutting a finishing thread without a guide, be careful to ensure that the die is screwed on 1-1.5 turns evenly, without distortion.

Advice: cut at least 5 turns, and be sure to screw the tap onto the bare thread, and count the number of turns, it should be 5, while on an iron pipe with flax you need to screw at least 4.5 turns!!! So don’t be lazy, if the tap is screwed on with fewer revolutions, be sure to trim the thread!!!
If you screw it on by 2-3, then after a short time 1-2 turns will rot, and the tap will fall off, and there will be a flood. How to properly wind flax on a thread, read.

Here is the process and tips on how to properly cut a thread on a pipe with a die with your own hands, you can watch the video.

When performing work related to the installation of plumbing or heating, it becomes necessary to cut threads on pipes. To do this, you can take a pipe and head to the metal rolling mill, where the threads will be cut in a matter of minutes. However, this method has not been relevant for a long time, since there are other options that do not require transporting the pipe to production.

Existing threading options

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

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

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

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

A die (another name for a die) is the simplest device intended for cutting external threaded connections on pipes.

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

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

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

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

Typically, pipe clamps are supplied complete with dies of various diameters. Having such a set, you can always cut threads on a pipe of any diameter.

How to cut a thread on a pipe with your own hands

To make threading on a pipe with your own hands, you initially need to perform a number of preparatory measures:

Carefully clean the tube in the area where you plan to get the threads.
Clean the end part of the product with a file.
Lubricate the working area to reduce resistance.

In order for the thread cutting process to be convenient and the end result to meet the requirements, before carrying out the action you need to secure the product in a vice. This will allow you to fix the part so that you can perform the necessary actions with both hands. After this, the following actions are carried out:

A wrench with a die of the required diameter is used, with the help of which a rough pass is carried out. In this case, it is important to keep the die strictly perpendicular to the pipe.
The roughing pass is the basis of thread cutting, so do not rush and perform the actions slowly but efficiently.
A rough cut allows you to get 2-3 threads of thread. This is exactly how many threads are needed for the tool to take a secure position.
The next step is to twist the rough die and use the finishing die. With its help, the required number of threads is cut on a pipe that is planned to be installed in a water supply or heating system.
After each pass, you need to make 0.5 turns back to clear the cutting area from chips.
At the final stage, you should use the third die, which carries out a control pass.

When threading, it is important that all actions are performed slowly, and with each subsequent turn the cut area is cleared of metal shavings.

How to cut threads on a pipe near a wall

Often thread cutting needs to be done on site when the pipeline is fixed in one part to the water supply or heating system. In hard-to-reach places, it is impossible to cut threads on a pipeline installed near a wall using a die and a wrench. For such purposes, you will need to use a thread-cutting device such as a clamp with a ratchet. With its help, the thread cutting process is simplified several times.

The procedure for thread cutting with a manual die is carried out as follows:

A nozzle of the appropriate diameter is fixed in the clamp mount, after which you can begin the procedure itself.
The surface of the pipe - the working area - is cleaned.
The area to be cut must be cleaned until a metallic shine appears.
A chamfer is made at an angle of 45-60 degrees.
The material is lubricated with Litol or Solidol.
The key is placed on the working area of the pipe.
Moderate back-and-forth rotations of the instrument are performed.

As with a die, when working with a die, you need to make half a turn back after each new thread to remove the metal edge. To facilitate the threading process, you can use an electric die, but it is rational to purchase such a tool only if you need to use it every day.

On pipes you can cut not only external but also internal threads, for which taps are used. However, the need to obtain threads on the inside of the pipeline arises only in rare cases. Knowing the features of self-threading, you will never have problems with the installation of water supply and heating systems.

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

Will need

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

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

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

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

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

Cutting a thread on a pipe

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

We also coat the cutters on the die.

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

In theory, the clamp is rotated with a specialized tool - a ratchet, but since we have a one-time job, it will not be profitable to purchase an expensive tool.
We take an adjustable wrench and adjust its size to the rear skirt of the clamp.
Rotate the tool, making several turns around the pipe. The cutters are now engaged.

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

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

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

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

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

How to cut threads on a pipe at home. Cut a thread on a 1 inch pipe

What do I use to cut threads | Santechscript

I cut the threads on the pipe with a tool or a clamp.

To cut threads on a pipe with a diameter of 15 (aka 1/2″, aka half an inch), I usually use a tool in a tool holder, which I put on the prepared section of the pipe, with the side that has edges; due to its length, it acts as a guide, which is important for uniform grip of the leech. I lightly press the end with my hand and rotate it over the edge with an adjustable wrench, clockwise.

It is not always possible to use the guide side, this is due to the fact that the pipe cut for some reason is made very close to the insertion into the riser, then you enter from the side of the riser. In this case, you need to be more careful, keep the angle perpendicular to the axis of the pipe, otherwise the thread may go crooked and the fourth turn will push the pipe right through. Actually, if the chamfer is removed evenly along the entire diameter, then the entry will go smoothly, and so will the entire thread.

You can cut the thread with a clamp, but usually a pipe of this diameter is used for wiring, and it is not possible to use a wrench due to its massiveness.

Everything for pipe carving.

On a pipe with a diameter of 20 (aka 3/4″, also known as three-quarters of an inch), I cut the threads with a die, although just in case I also have a three-quarter thread in the holder. For the same reasons as in the paragraph described above.

And I cut pipes with a diameter of 25 (aka 1″, aka inch) and diameter 32 (aka 1 1/4″, aka an inch and a quarter) only into clamps with a ratchet. This is due solely to the complexity of performing this work. Using clamps the process is much simpler, easier and faster.

In the photo, in addition to the screws and clamps with a knob, I imagined that I use universal, plumbing sealant and plumbing flax to seal the threaded connection. After cutting the thread, I apply sealant to it, trying to distribute it evenly over all turns, and after that I wind the flax, I talk about this in detail (and show) in another article, I will leave the link below.

Connections are not only threaded.

In my profession, I have to connect polypropylene with cast iron when installing a sewer system. Basically, this connection is made using a transition rubber sleeve, which, coated with sealant, you insert into the socket of a cast iron pipe or fitting, and then insert a fitting or polypropylene pipe coated with sealant into it. Due to this, the connection is airtight.

The photo shows a heel of varying thickness; it is also used when installing sewer systems, by compacting it into the gap between the materials described above. Using a heel is convenient because you can unravel it and select a strand of the required thickness. Its use is relevant in cases where the transition cuff does not fit in size; such cases are not frequent, but still occur.

Video: clamp - a tool for cutting threads on a pipe:

Perhaps these articles will be useful to you: How to cut threads on a pipe. 10 important nuancesHow to wind a thread hermetically (video)How to cut easier with a grinder

If you have questions or additions, write in the comments column. That’s all for today, good luck in your work, best regards Andrey.

Tired of looking for information from practitioners? Subscribe (scroll down the page) and the information will find you. Clicking on the social network icon is the best reward for my work.

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How to cut a thread on a pipe with your own hands: make the thread

Very often, during the installation of pipelines or during its repair, it is necessary to replace old pipes with new ones. To do this, new pipes must be cut with suitable threads.

An experienced craftsman is unlikely to have any problems with all this, because over the years of work he has “taught his hand” and can do everything almost effortlessly. Moreover, professionals have all the necessary tools for this.

What if it is needed by an ordinary person who does not know how to carve a pipe? Plumber services are often prohibitively expensive.

So, first you need to remember that pipe threads are always cut. In addition, you don’t have to think long about the sizes, because in all apartments the pipes are standard, and their sizes can be 1″, 1 1/4″, 3/4″ or 1/2″. Therefore, to cut threads with your own hands, you need to acquire a die or pipe clamp.

How to cut a thread on a pipe using a die

First we will talk about the die. Sometimes you can hear this instrument called a “lerka,” although the latter term dates back to the times of the USSR. This is a fairly common tool that can be purchased at any metal-cutting tool store.

But before you go and buy yourself a die, you should find out the size of the pipes on which the thread will be cut. Basically it is half an inch, three quarters or an inch. When the size is known, a regular die with a cylindrical pipe thread is purchased. On such tools, the markings have the letter G, that is, a half-inch die will be marked G1/2″. With the use of such tools, pipe threads will be made correctly.

Since holding a die in your hands, you cannot screw the thread, you need to get a die holder. Its cost may be equal to the cost of the die, or may even exceed it. If the work will be done only once, then you can purchase a Chinese die holder, the price of which is lower than the cost of a domestic one. If you want to buy a quality instrument, then it is better to pay more money, but become the owner of a domestic holder. The reason for the low reliability of the Chinese die is the raw material silumin.

How to cut a thread on a pipe with a die is a rather complicated process. At least for those who have never done this before. The whole point is that the die does not have a guide, so it is very difficult to cut the thread evenly right away, and it constantly “bumps”, which should not be allowed. That is why, if you have no experience in cutting threads, then it is better to stock up on a special tool called a die.

Threading a pipe using a screw

Now about how to cut threads on a pipe with a clamp.

This tool is very convenient. Moreover, even a person who has never done anything like this in his life can do everything correctly.

Everything is very easy, and the reason for the ease is the special guide that the tool has. A pipe is inserted into this guide, after which the person only has to twist the die, and the thread will be cut independently almost without effort.

To make the process easier, you can purchase a special ratchet that will allow you to twist the clamp without removing the tool, even if there is little space for this.

If you need to cut threads on a pipe of large diameter, that is, from one inch, then it is better to get a special extension for the ratchet. This will make the lever larger, which means less effort for cutting. Among other things, when cutting threads on pipes manually, you need to water the pipe with a special thread cutting fluid or ordinary machine oil.

This step will make the process easier. Moreover, this technique can be used when cutting threads in any material and with any tool, be it a tap, a die or a die. As you can see, cutting threads with a die greatly simplifies the process of creating threads, but in turn, this leads to increased costs.

There are also special electrical clamps where cutting threads on a pipe does not require any additional effort.

The principle of operation of such a tool completely coincides with the principle of a manual clamp, but instead of the effort exerted by a person, an electric motor works here. Thus, thread cutting will not be difficult for a person at all, since all he will need to do is install the device on the pipe, having previously lubricated it with oil, and turn on the power plug.

phoenix-master.com

Home craftsmen today don’t often think about how to cut threads on a pipe. Most projects are implemented using alternative materials. But such a need sometimes arises. Thanks to basic skills, you will be able to independently carry out simple repairs at home or in other conditions.

Basic Concepts

A threaded connection is essential if it is necessary to install a shut-off valve, adapter tee or coupling on a metal pipe. Very often joints become unusable and have to be redone. The thread is characterized by:

depth;
walking;
profile;
profile angle;
location.

Depending on the profile and pitch, threads are distinguished:

Inch. Has the shape of a triangle. It got its name from the units in which the outer diameter is measured. Used in the assembly of plumbing and heating parts. Conventionally, they are divided into pipe and fastening. The second has a larger pitch to ensure better fixation.
Conical. The main use of this type is to ensure that the connection is sealed without the use of various sealing materials.
Cylindrical. This is a type of inch thread with a finer pitch. The upper edge of the profile is smoothed and resembles part of a cylinder. Usually the thread pitch coincides with the inch pitch for parts of suitable diameter.
Trapezoidal. Has an apex angle of 30°. Most often used in bolted connections to provide greater reliability during fixation. A thread whose sides resemble an isosceles trapezoid is called persistent.
Rectangular. Used for the same purposes as the previous type.

Based on the location of the cutting, the following are distinguished:

external;
internal.

Each of these types requires an individual approach and is intended for specific purposes.

Preparatory stage

The quality of the final product depends on how responsibly this stage is completed.

The tool that will be used to perform the work must be in good condition. There should be no rust on it. For this purpose, during long-term storage it is coated with a preservative lubricant. Clupp cutters must be well sharpened.
If the pipe has already been in use and there is paint on it, then it must be thoroughly cleaned. This is done with a file, grinder and grinding wheel, sandpaper or hair dryer.
Using a grinder or hacksaw, the plane of the end is drawn out. To do this, a small piece is cut off to make a right angle relative to the axis.
The burrs are removed with a file.
The chamfer is removed in such a way as to create a small cone.

All work is done with a die or a ladle. These are identical concepts and are synonyms. Depending on the design they can be:

Adjustable or sliding. Usually they contain several incisors, the distance between which can be changed. They are especially useful in cases where the pipe profile is uneven due to deformation or manufacturing defects, but threading is still required. Most often they are installed in clamps that provide them with good fixation. With the help of such products, threads can be cut in several passes, which increases its accuracy and quality.
Monolithic. They are a small cylinder with a hole in the middle. Such a tool is clamped into a special die holder. Usually secured with one or more bolts. With this tool, cutting is made in one pass.
Conical. Designed for cutting the corresponding threads mentioned above.

The lathe is selected depending on the diameter of the pipe being processed, as well as on the direction of the thread - right or left. All designations are applied to the packaging or directly to the instrument itself. The whole process will boil down to the following steps:

The workpiece is fixed. If it is not secured in any system, then it is clamped in a vice. In the case when cutting will be done on a water pipe or heating pipe, it is necessary to make linings to immobilize it.
The end of the prepared pipe section is lubricated with machine oil or grease. If these components are not available, then you can use what you have on hand - even lard.
The surface of the tool cutters is also lubricated.
The die holder with the leech is brought to the end of the pipe. This must be done exactly at a right angle. This is much easier to do with a die holder with a guide.
At the same time, it is necessary to rotate the thread cutting tool and press it against the pipe. Coupling has to happen. Thus, it is important to cut the first 2 turns.
If you do not use a die holder with a guide, you will need to constantly ensure that the angle remains 90°. If you do not comply with this requirement, then a imbalance may occur. This threatens that the thread will be torn off, the tool will be damaged, or the required step will not be observed.
Do not cut in a continuous pass. The process will produce metal shavings. In order to remove it, you need to make one turn in the direction of movement and half a turn back. It is thanks to this that accumulated waste will be removed.
As you progress, you also need to add lubricant.
After completion, you need to unscrew the eyeliner and go through it again to make the final liner.

Thread cutting using a die uses the same mechanism. In addition to this, some products have the ability not only to move the cutters, but also to rotate them. In this situation, you can use the same tool to perform both finishing and roughing passes. When using such a unit, you must be very careful during the initial stage. This is due to the fact that thanks to the ratchet handle, you can apply more force than with a conventional leash holder. If you don’t set the angle correctly at the very beginning, then you can ruin the entire workpiece and not even notice it. The clamp is inconvenient to use in cases where the pipe is already installed and is close to the wall. You will need to either bend it using a wedge or hollow out part of the plaster so that the nozzle fits well and does not move.

Using a power tool

An electric thread cutter can carry out the planned work several times faster, and the quality of the final product will be much higher. The sequence of work will be as follows:

The pipe is cut to the required size. The most acceptable result is obtained when using a reciprocating saw with a guide.
There is no need to remove the chamfer, as for the chamfer. By the way, this rule is also relevant when using a manual clamp.
A special holder is placed on the pipe. He acts as a guide. It is important to clamp it well.
The power tool is brought in and inserted into the receiver of the holder. The clamp is put on the pipe.
Lubrication is carried out using a special composition.
Then the unit does everything automatically.

There are times when to assemble a structure it is necessary to cut an internal thread in a pipe. For such purposes, a completely different tool is used - a tap. It is a small metal pin, at one end of which there are external incisors. To ensure everything goes right, you need to follow these steps:

Using a caliper, the internal diameter of the pipe is measured.
The corresponding tap is selected exactly based on this value.
All burrs are removed using a file.
The surface is treated using a metal brush.
Tap number 1 is clamped in the holder and inserted into the pipe. It will remove 70% of the material during the pass. The remaining 30% is removed with a number 2 finishing tap.
In order to remove chips along the way, the same rule applies as in the case of a lecher.
If a thread needs to be cut in one of the pipe walls, then a hole is drilled with a drill. The drill must be clearly perpendicular. This is important, because otherwise you won’t get high-quality cutting.

Nuances

There are some secrets that have been developed over the years and are rarely talked about. Here are a few of them:

You can make your task easier when using an ordinary leveler with a special guide. It is a small clamping mechanism with a thread at the end. It must be inserted into the middle of the pipe until it stops against the side and the jaws must be opened. The die is screwed onto the thread of the clamp and then goes smoothly and accurately along the pipe.
Some craftsmen recommend using dishwashing detergent as a lubricant. No matter how absurd it may sound, it provides excellent passage, and the chips are not torn, but solid, which indicates the best quality of the work done.
If you plan to install a brass tap on a steel pipe, you need to cut the thread so that when screwing on the locking mechanism, you get 4-5 turns. This will guarantee good fixation and long service.
The design of the die is such that the thread is slightly conical, i.e. the last turns are less deep than the first. In this case, the bends are not wound completely. To compensate for such a deviation, it is necessary to walk after the clamp with another ordinary leer.
There are situations when a thread needs to be cut on a pipe that extends a short distance from the wall. In this case, you can use a ruler or trim the die guide. This will not affect performance, but will provide greater convenience.
When replacing cutters in a die, be sure to follow the sequence in which they should be installed. Most often they have numbers on them that correspond to the receiver.
If the thread needs to be cut on a pipe that is recessed into the wall, then you need to do this. A small area is knocked out around the pipe to accommodate the plug. You can rotate the slicing mechanism using the T-shaped handle. A hexagonal head with slots is placed on its end. It is selected in such a way as to enter through the external hole of the die and cling to the space between the incisors.

Using the methods and methods listed above, you will definitely get an excellent result, which you will achieve with your own hands. If you know some secrets about where to cut threads and how best to do it, share them in the comments to this article.

Video

The technology for cutting threads on a metal pipe is demonstrated below:

How to cut threads by hand with a die and tap

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

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

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

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

External thread cutting with a die

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

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

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

Operating procedure

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

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

Nominal diameter thread, mm	Rod diameter, mm
Nominal diameter thread, mm	nominal	minimum

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

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

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

Tapping internal threads

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

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

Tapping technology

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

Nominal diameter

thread, mm

Step, P

Drill diameter

threaded

2	0,4	1,6
3	0,5	2,5
3,5	0,6	2,9
4	0,7	3,3
5	0,8	4,2
6	1	5,0
	0,75	5,25
	0,5	5,5
8	1,25	6,8
	1	7,0
	0,75	7,25
	0,5	7,5
10	1,5	8,5
	1,25	8,8
	1	9,0
	0,75	9,25
	0,5	9,5
12	1,75	10,2
	1,5	10,5
	1,25	10,8
	1	11
	0,75	11,25
	0,5	11,5
14	2	12,0
	1,5	12,5
	1,25	12,8
	1	13,0
	0,75	13,25
	0,5	13,5
16	2	14,0
	1,5	14,5
	1	15,0
	0,75	15,25
	0,5	15,5
18	2,5	15,5
	2	16,0
	1,5	16,5
	1	17,0
	0,75	17,25
	0,5	17,5
20	2,5	17,5
22	2,5	19,5
24	3	21
27	3	24
30	3,5	26,5

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

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

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

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

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

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

tehnouzel.ru

video instructions for DIY installation, features of cutting near the wall, thread-cutting tools, machines, price, photo

Today, most homeowners, when carrying out renovation work in a house or apartment, prefer to use polypropylene for heating and plumbing, or, in extreme cases, plastic. But the water supply from the outside (especially for apartments in multi-storey buildings) is still done with metal, therefore, the question arises of how to cut a thread on a pipe near the wall.

Whatever you say, it is quite difficult to do this due to limitations in free space, so we will draw your attention to some of the nuances of such production, and will also demonstrate a video in this article.

Thread cutting

Tools

Explanation. A thread-cutting tool for pipes and fittings in the form of a thick plate with a threaded hole in the center is called a thread-cutting tool. Where there are slots for the formation of cutting edges. A die, unlike a die, is a one-piece tool, therefore, the thread is more accurate, especially on blanks with a small cross-section. It can be used for cutting left-handed or right-handed threads, but there is also a universal option - marked with markings LN.

As you understand, the main device used for cutting threads on pipes is a threader, but by itself it is not effective, since it requires a lever to operate it. You can immediately make a reservation that the lever must be specialized, for example, if you clamp it with a gas wrench and try to cut the thread, the lever will most likely burst.
The cutting tool is fixed in a clamp - this is a frame with handles - so, the frame compresses a prismatic or square blade, increasing its strength, and the handles, screwed on the sides, serve as a lever. But such a device is convenient in cases where there is room for levers, but if the blank is located against the wall, then they have to be constantly unscrewed and tightened again. Therefore, here it is much more convenient to use a pipe clamp with a ratchet, as in the photo above - the presence of a wall on one or even both sides (corner) in this case will not be a serious obstacle.

An electric clamp or machine for cutting threads on pipes is also a hand tool that can be used in any plane, moreover, the head can be inserted from any side, therefore, both sides are working. Thanks to the powerful gearbox, you will hardly have to exert any effort when cutting threads, but its price, accordingly, is also much higher than the same ratchet. Despite its versatility, such a tool, compared to a lever die, is quite bulky and requires operational space for cutting threads on a blank.

First of all, the instructions require cutting the pipe evenly, since otherwise the thread will move diagonally, therefore, the thread will be unclear, with a broken pitch, or you will not be able to catch the edge at all.

Here, especially if the blank is located against the wall, no marking will help you - for an even cut you need to develop an accurate eye. Even if you didn’t succeed in making an even cut the first time, you can always use the same disk to trim the higher edge so that you get an angle of 90⁰ with respect to the pipe wall.

It is very important to pay attention to the condition of the metal - given that such work is usually carried out with old plumbing or heating, the walls can be corroded, and cut threads will make them even thinner. Therefore, you should either get to the “living metal,” as craftsmen usually call it, or even replace the old pipe with a new one.

On an even cut, you need to remove the chamfer, which will allow the blade to “catch” on the metal, just try to ensure that the bevel is uniform around the entire circumference - this way the head will screw on evenly.

Recommendation. To cut threads, it is imperative to lubricate the working blank so that the edge does not become “torn.” Machine oils and grease are used for this, but practice shows that the best lubricant in such cases is raw lard, which is rubbed onto the surface being treated.

After you are convinced that the cut is smooth and the chamfer is removed from it correctly, lubricate the working surface of the blank (preferably with lard) and place a machine (threading pipe set) on its end. After this, apply the head of the wall to the cut end strictly at a right angle and, pressing from above, slowly, without sudden movements, begin to rotate the handle.

You should press until the blade thoroughly bites the metal - to do this you need to cut at least one and a half to two rings. After this, the pressure can be stopped - the machine will advance thanks to the resulting hook.

After cutting the first steps, you need to turn the machine in the opposite direction - this will allow you to chop off the chips, since otherwise the movement will be very difficult.

In addition, do not try to go through the entire area remaining after the hook in one go - after two or three turns, reverse the stroke to get rid of chips, and add lubricants as necessary. If you use a ratchet, be sure to check its idle speed before starting work and, if necessary, adjust it yourself.

Conclusion

The technique described in this article is suitable for almost any blank with a cross-section up to 1 inch, since threading a 1 2 (1/2 inch) pipe can be done in the same way as 3/4 inch, and so on. On a larger pipe, the thread is cut either on a lathe, or a fitting is welded to it. Good luck!

hydroguru.com

I have already described the thread cutting process itself in the article “How to connect a heating radiator”, but based on questions received by email from readers of my blog, I decided to describe in more detail how this should be done.

In order to cut a thread, you will need the following tool:

die holder, lerka
rough thread cutting die
finishing die
grease, machine oil or a piece of lard
grinder or file

They are also called first pass and finish dies.

Why I recommend using two dies:

Firstly, it is easier to cut, and secondly, tool wear is reduced, and with the current quality, this is very important, since now you will cut 3-4 threads, and you can throw away the die.

If you are cutting a thread on a water or heating riser, or a tie-in to an apartment, be sure to make sure it is in good condition, otherwise you risk breaking the pipe!!!

2. Lubricate the thread and the teeth of the die with grease or lard.

4. When you have cut the rough, take the 2nd die, again lubricate the threads, the die for finishing threads, and repeat the same steps.

And now some tips and nuances.

Do not buy taps with 3.5 turns of internal thread, even if they are thick-walled, such valves can be screwed onto fittings with brass threads; they are not suitable for water pipes or iron pipes.

Be sure to cut the first thread through the guide so that the thread does not become skewed.

If you are cutting a finishing thread without a guide, be careful to ensure that the die is screwed on 1-1.5 turns evenly, without distortion.

Advice: cut at least 5 turns, and be sure to screw the valve onto the bare thread, and count the number of turns, it should be 5; when installing a ball valve on an iron pipe with flax, you need to screw at least 4.5 turns!!! So don’t be lazy, if the tap is screwed on with fewer revolutions, be sure to trim the thread!!! If you screw it on by 2-3, then after a short time 1-2 turns will rot, and the tap will fall off, and there will be a flood. How to properly wind flax on a thread, read here.

Here is the process and tips on how to properly cut a thread on a pipe with a die with your own hands, you can watch the video.

Good luck to you!!!

roma100471.ru