Determining the dimensions of the pipe. calculating the pitch and diameter
For the most accurate determination of pitch and the correct diameter of the pipe threads, given the complex system of calculation according to GOST 6357-81, it is necessary to use special devices. Among the most common tools are a caliber, a thread gauge, a micrometer, a caliper. If you have a table of parameters, you can take a special device. a socket or a coupling with cut on them calibrations, the value of which you know.
An even simpler way is to use a standard thread gauge. This device consists of a set of measuring plates that are applied to the thread grooves from the outside or inside and then the required value is determined by the plate number on the thread meter. A micrometer or caliper will only measure the outside diameter of a pipe thread, but this is sometimes enough to determine the pitch and inch. There are two basic dimensions used today for constructing domestic piping from pipes with an inch connection type:
In this case, an inch connection in the pipeline is used only on metal and plastic pipes of small and medium-sized. In all other cases it is recommended to use a welded type of connection to increase reliability at the joints. Thus, to determine how to connect the pipe, you need to use several tables, including the table of sizes of the pipe itself.
Types and Features
The task of threading a pipe with a die is realized quite easily if the part is selected appropriately. There are several types of dies are divided:
- Metric. Measures parts in millimetres, even-sided triangular profile, smaller pitch.
- Thumbnail. Measured in inches, profile type. isosceles triangle, pitch larger. Large profile produces reliable threads.
The inch die is suitable for threading in water pipes, while the metric die is suitable for fasteners. Threading is also categorized into left-hand and right-hand threads. What does it mean?
Right-hand threads are characterized by turning the nut clockwise, and left-hand threads are characterized by turning the bolt in the opposite direction. For quality threading and reliable connection, the rod should be 0.2-0.3 mm smaller than the external dimensions of the thread.
What are the tubing dies and how to work with them?
You always need the right tool to make the job easier. To leave a thread on the pipe different techniques are used. But most often a pipe cutter is used. Tubular die is a metal construction, which is used to apply the thread to the pipe. This is done by screwing the die on the pipe. Consider the main types of dies, as well as their size range.
I thread the pipe with a pipe lance or a crescent.
For threading a pipe with diameter 15 (aka 1/2″, aka half-inch), I usually use a pipe lerk in a tool holder, which I put on the prepared cut of the pipe, the side that has faces, due to its length it serves as a guide, which is important for uniform meshing of the pipe lerk. I lightly press into the end with my hand and turn it clockwise with a crescent wrench
It is not always possible to use the guide side, it happens due to the fact that the cut pipe for whatever reason, is made very close to the mortise in the riser, then you do approach from the side of the hole. In this case you need to be more attentive, keep the handkerchief perpendicular to the axis of the pipe, otherwise the thread can go crooked and on the fourth turn it will break through the pipe. Actually if you have chamfered the whole diameter evenly then the approach will be even and so will the whole thread.
It is also possible to cut a thread with a club, but usually the pipe of this diameter is used for distributing and it is not possible to use a screwdriver because of its massiveness.
On the pipe diameter of 20 (aka 3/4″, aka three-quarter inch), threading clincher, though just in case I have a three-quarter lerk in the lerko holder. For the same reasons as in the paragraph above.
And pipes of diameter 25 (aka 1″, aka inch) and diameter 32 (aka 1 1/4″. a.k.a. one-and-a-quarter inch), I only thread with a ratchet. This is due solely to the labor-intensive nature of this work. Using clips the process is much simpler, easier and faster.
In the photo, in addition to the lock pick and tongs with a screwdriver, presented that I use to seal a threaded joint, namely, universal, sanitary sealant and sanitary flax. After the thread, apply sealant to it, trying to distribute evenly over all the coils, and then wind the linen, details about this tell (and show) in another article, the link will leave below.
Connections can be not only threaded.
In my profession I have to connect polypropylene with cast iron, when installing plumbing. Basically, this connection is made through the transition sleeve rubber, which blotted with sealant put into the bell of cast iron pipe or fitting, and already in it you insert the fitting blotted with sealant or a pipe made of polypropylene. It makes the connection airtight.
The photo shows the kabolka, different in thickness, it is also used in the installation of sewers, by tamping in the gap between the materials described above. It is convenient to use a pipe threader because it can be unscrewed and a strand of necessary thickness can be selected. Relevant is its use in cases where the sleeve does not fit the size, such cases are not frequent, but still occur.
If you have any questions or additions, write in the Комментарии и мнения владельцев section. For today that’s all, good luck in your work, Sincerely Andrew.
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Threading of pipes
Suppose there is a pipe that needs to be connected to another pipe. You can of course use and welding, but this is only possible if the iron with the iron to connect.
And if you need to connect the metal pipe with a plastic pipe, you need a thread. There are, of course, other ways, such as Gebo, but the threads are better.
In this post I’m going to talk about how I thread metal pipe.
So, we have the pipe cut off and cleaned of paint/dirt. Next, we need a thread cutter. They can be manual or electric.
A little bit about the electric one: There is a set like this. 4 lance for different diameters and an electric device. Here is an example of how it works:
It is very convenient if you need to thread a small section of pipe that you have in the shop. That way you don’t have to rack your brains about how to hold the pipe. The thing is very handy, but not very cheap. If you thread a couple times a month you don’t need to spend money on an electric tapping machine. There are some disadvantages with this device. One such disadvantage is that it quickly heats up and even overheats. Of course, if you have to cut a single thread, no problem. But if you need to make more than two swaps (long threads) at least on an inch pipe, then it is an impossible task for him. it has another important disadvantage, it is too wide. Do not put it on the pipe if it is close to the wall. For this reason, in such places, we use a hand threader or just a lance.
Handheld threader, a little more compact, but I usually don’t even use a handheld one. There’s a thing called a Swede! Let’s go:
We see a painted pipe. The pipe should be clean. The arrow shows the roughness, it is a leak of construction material, which is also painted on top. If this layer is not removed, then you can not put the pipe on the pipe. Cleaned and take the needed size of a lance: In the picture we can see two lances, a good one and a cheap one. Cheap larka threader is good, but while it’s new it doesn’t cut deep enough, so screwing something on it is a problem. In some cases, having two lancers makes it easier for us. If the first one does not cut the thread to the right depth, then it is easier to twist. Then we put a good riser on the same half thread and thread it again. Do it only if the pipe has a large diameter, and use a good pipe sharpener for cutting small pipes. 🙂
And so, we’ve taken the crow bar, cleaned the pipe and now we start the threading process, clockwise. Before you cut it, it’s a good idea to oil it a little bit. Either oil/lubricant/brake fluid or a grease specifically designed for that purpose. Here’s a bunch of photo examples for you:
You can’t cut a thread in one fell swoop. Cut it gradually, half a turn forward, then a little backward. There is no hurry in this. You can bend the pipe and stay without a pipe sharpener.
After threading, try to screw what you are going to install on it. That’s how we check how well we’ve threaded it and if it’s long enough. If it screws in well you can seal and mount.
Now a little bit on the possible nuances. After you have cut the thread, take a flashlight and carefully, from all sides, inspect the new thread. The thing is, if the pipe is old, there is a risk that the joints of the threads can be cut through. Not only that, but it happens that the pipe is simply twisted and a part of the thread remains in the pipe. This sucks. It’s very, very hard to get it out of there. (in this case, do not disassemble the lerca, and it will turn into scrap metal, because the adjustment of the cutters, very fine). If the pipe sucks and you can not replace the pipe, do not cut the thread, install the Gebo.
What to do if the lance was too long and you can’t thread? Then you just have to cut off a part of the flair, but leave a place where you will grab it:
Not only that, if you cut the whole tail of it, you probably will not be able to evenly thread it. This very tail properly guides and aligns the threading device/lerf.
I think I’ve explained everything about threading. Good luck with that.
One of our regular readers, his name is Alexei, sent us a photo of another device that he uses to cut the thread.
Thanks Alexei. Here is a photo of it and a commentary:
The lumber is pulled out separately (in this case, it’s half an inch). But if you take the ring out, you can put in a three-quarter-inch blade.
There is also a removable ring on the guide. With this ratchet you can adjust the inside diameter of the guide. 3/4 or 1/2 inch.
This ratchet can be used to cut threads on half inch pipes and on three quarter diameter pipes.
The main thing is to make the engagement (to start cutting the thread straight) and then you can twist the guide if there is not enough space for it.
This ratchet can be reversed and threaded almost exactly.
Using the ratchet
They’re also called slicing dies. This threading tool is essentially a nut that has been fitted with holes. They create the edges for the cuts.
Depending on the shape, there’s a slicing blade:
Using such a device as a larka, you can quickly prepare a pipe product of any kind for connection.
The heading tool must be aligned strictly perpendicular to the face of the pipe. If there is any misalignment, there is a possibility of the thread being stripped, or the diameter of the thread may change. Either way, the final result is not satisfactory.
How to Thread Pipe EXTREMELY FAST
It is recommended to perform all work with the plier smoothly, without jerking. While operating with this tool, from time to time it is necessary to lubricate the cutters and the surface part of the thread.
After the final coil is completed, the tap should be returned upwards and the thread is threaded again.
All about dies
Tap or lacer is a device used to cut various types of male threads. It is represented by a small nut on which there is an edge and a chisel tap. The threading tool may have a thread pitch ranging from eight to ten threads.
thread pitch is the distance between successive threads.
You can measure the thread pitch with a special device. a caliper.
1/8″ to 2″ sizing dies. You can buy them in any online store, the price starts from 30, depending on size.
You will need
Kupp. threading tool, like dies, but it is a nozzle with a guiding skirt. It must be purchased at a plumbing store. There is no deficit on them, so you will find no problem, even in the village.
In this case the Chinese version, pretty good.
It costs about 200-500. It all depends on the diameter and markup. Running models for 1/2″, 3/4″ and inch diameter as in my version.
You can ask plumbers for a Soviet analogue, if possible. Then it will be free of charge for you.
Threading internal pipe threads
Adapters, elbows, couplings have internal threads; they are screwed on the pipe without reducing its inner passage. But if you want to make your own pipe connectors, you need this skill.
In this case taps are used for cutting (in the photo). It is a metal rod that has a cutting part. The edges are made by separate segments, separated by longitudinal strips for chip evacuation. The tap has a square shank, to which a screwdriver is fitted and rotated. This kit comes with two taps, one for roughing and one for finishing.