How to thread a copper pipe
Tapping the male thread with a die
To thread a copper pipe, you will need the following tools and materials: die or tubing tongs, a ramrod, a file, a vice, a caliper, machine oil and a lead oil.
The most common are round dies (lerks). They can be made in one piece or cut. The diameters of solid round bars are standardized. This allows the appropriate variant to be selected from a large range of dimensions, e.g. M10, M12, M14, M16.
The special feature of round dies is the ability to adjust the diameter of the thread within the range of 0,10,25 mm. However, they have reduced rigidity, which affects the accuracy of the resulting profile.
Insert the tap into a tap holder of suitable size. After that it is fixed by means of screws. In case of external pipe threads, ratchet dies are often used. They make it easy to reach hard-to-reach places, such as the wall.
The thickness of a rod is chosen on 0,10,25 mm less diameter of the external thread. For example, for M6 with coarse pitch it is 5.805.90 mm; M8. 7.807.90 mm; M10. 9.759.85 mm. Measurements are taken with a caliper. The diameters of rods for medium metric thread of accuracy class 6g are shown in the table below.
To ensure better plunge cuts, a chamfer is sawn on the end of the rod. Its width should be 1. 1,5 mm for M6 M18. The workpiece is lubricated with machine oil, which facilitates subsequent work and gives a better surface finish.
The strip is applied to the end of the rod so that its plane is perpendicular to the axis of the bolt to be cut. Then turn the tongs with slight pressure clockwise (counterclockwise if the thread is left-handed). When the die will run into the rod by one or two strands, it should be turned a half-turn back for better removal of chips. After that 1-2 turns along the thread and 0.5 turns in the opposite direction shall be made again. Acting according to this scheme, the bolt is cut to the required length.
Diameter of the outer thread is checked with an ordinary nut or gauge-ring. If necessary, the pitch is controlled with a thread gauge.
A few words about GOST for pipe threads
When working with gaseous and liquid media, according to GOST 6111, if there is a need to implement detachable joints in the pipeline schemes, it is allowed to make such connections on the threaded base.
It is possible to make not only pipe threads, but also tapered threads (GOST 3662).
Despite the rare use of tapered thread in pipe connections, it is considered more convenient by the characteristics of screwing / screwing.
It should be recalled that the angle of taper of a tapered thread is directly related to parameters such as pitch and diameter. The allowable value of this angle cannot be less than 26°. The standard value of the apex angle of a tapered thread is 60°.
Pipe threads have a characteristic feature. they have a rounded profile tip. When threading standards are met, the rounding value is 10% of the thread radius size.
This threading technology allows for a significant reduction of internal stresses on the small area of metal occupied by the thread profile.
The established tolerances of GOST 6357, along with the cylindrical and tapered threads, provide for the performance of metric threads on pipes.
Here, the standard angle of inclination is 55°, which is due to the increase in the number of coils on the section of length equal to the section with the other type of thread.
The result is a connection with a higher degree of tightness, but the labor intensity when using such connections increases.
Existing GOST installations also provide the ability to perform thrust and trapezoidal threading on pipes. But in practice, these types of threading are not used because of their low operational strength.
In plumbing works, different ways of connecting pipes are used. The choice of method depends largely on the material of the pipeline and its “areas of responsibility”. Threaded jointing of parts is recommended for use in areas accessible to periodic revision.
Information on alternative methods of connecting pipes is presented in the articles:
Works with an electric thread cutter
Along with modern household appliances, homeowners use electric thread cutters. This tool is more commonly used when threading small pipe products.
In the complete set of such device there is a dovetail cutter for cutting of threads of different diameters and the electric thread cutter itself.
A pipe vise is used when clamping a piece of pipe product. In such a situation, locksmiths pull the trigger, after which an inch tapered thread is cut on the tubular piece.
Fast heating or overheating of the electric thread cutter can occur when cutting pipe threaded connections.
However, such risks do not arise if the installers are machining 1 pipe part. this expensive power tool is usually bypassed in such a situation.
If the male threads are being cut on an inch pipe product, then an electric thread cutter should be used with caution in such a situation. Using this large-sized tool, it is not always possible to thread pipe parts that are close to the wall.
- die holder;
- a roughing cutter (lead-through);
- a blanking (finishing) thread cutter;
- solidol;
- A piece of lard, oil from a car barrel;
- angle grinder, file.
When cutting a tube, 2 dies are used instead of 1 because it is easier to cut the tube this way. In such a situation, the service life and technical characteristics of the tool itself are increased.
Wherever the owner of the dwelling is engaged in cutting pipe threaded connections: on the water pipes or on the pipes of the heating system, he must first check the condition of the pipes.
If such a check is not made before beginning the work, the pipe will break quickly when threading connections.
When hand-cutting the tubing, fitters do the following
- first remove the chamfer. at the end of the pipe product, where the threaded sections of the tube will be located;
- further, such sections of the pipe and the teeth of the dies are lubricated;
- Then the die holder, on which the feed-through die is prefixed, is pressed hard against the pipe product, resulting in a meshing action;
- Then locksmiths turn the tool clockwise. make threading in 5 turns.
If there is any resistance in such a situation, the fitters make a half-turn backwards. The sawdust will eventually chip off and it’s easier to make clockwise turns.
When carrying out such work, a finishing die is used, which is lubricated in advance. Fitters do the same thing as when roughing.
Tapping pipe threads at a rapid pace is prohibited. Outer threading of threaded sections on pipe products must be done at a slow pace, while making movements of the tool in half a turn forward.
If you don’t follow such a rule, the pipe threads will bend and the threading lathe will be irrevocably ruined when threading.
According to professionals in this business, it is better to use not cheap, but expensive and durable dies when threading the tubing.
The difference between the two can be seen visually. At the same time, when using a cheap die, it is possible to make a strong pipe thread connection for a short period of time. after repeated use of such a tool, the external thread does not have the required depth.
Also, when threading metal parts manually, in addition to dies, locksmiths also use tongs for tapping pipe.
Choosing a threading tool
To manually thread metal parts, you use taps for female threads, dies and dies for male threads. We are interested in the latter: they are the ones you need for working with pipes. Both of these tools, although they perform the same function of forming a helical surface on the outside of a cylindrical part, still have some design differences.
The die is a large nut with cutting edges inside for removing material from the surface of the workpiece and holes for removing chips. It is screwed onto the workpiece, thereby threading. For those new to the job, it can be difficult to use the tool in any way, the slightest twist will cause a defect and the workpiece will be destroyed. So if you are a beginner, you are better off using a manual cluppet.
This tool is used especially for making pipe threads. In essence, it is the same die, only in a metal cylindrical holder. Inside the cylinder there are high-carbon steel cutters, in addition there are clamping rings and bolts for better fixation on the workpiece it excludes misalignment during work and helps to achieve high-precision threading. A handle is needed to turn the tongs. It can be supplied as a set with it or an ordinary gas wrench can be used instead. Choose a hand clupp should be under the diameter of the pipe, for example 3/8, 1/4, 1/2 or 1 inch. There are tools with interchangeable cutters that can be used with different pipe sizes, such as 1/2 inch and 1 inch.
How to thread a pipe: the easy way
Any owner of a city apartment or private home thinks about improving his home with his own hands. In such a situation, the owner of the premises must have good tools and certain skills.
This article describes in detail how to thread the pipe with your own hands. how to thread the tap manually.
Basic ways to thread a pipe and how they differ
When installing a new sewer system or replacing old pipes, you should know how to thread the pipe, as this will simplify the selection of the right plumbing fittings and the pipes themselves. Let’s get acquainted with the types of threads, for what purposes it is needed, the main ways in which you can determine its size, as well as what tools can make it. Also consider the process of threading by hand or with automatic devices.
How to use a crescent
The following steps are for threading pipes by hand:
How to Thread Pipe; A Beginner’s Tutorial
- Flattening or reducing the thickness of the pipe edge before threading. This can be done with a file or hammer.
- Lubricate the base of the pipe before proceeding. This will improve the penetration of the cutters into the base, and will increase the life of the tool. Lubricants that can be used include Solidol, Lithol, or regular motor oil.
- Threading must be done slowly and gradually. Make one turn forward, then half a turn backward to remove metal shavings. The movements of the tool should be carried out smoothly to prevent the thread ring from slipping.
- To thread a pipe with a c-clamp, you must clamp the pipe in a vise or hold it with a wrench. This is done in order to prevent the turning of the workpiece during its machining.
The presence of the product in question will allow you to quickly and efficiently thread the pipes where you need it to make the connection.
How to thread a pipe internally?
In some cases, internal threads are required, which can also be tapped by the use of hand tools. Often a tap that has three main parts is selected for this kind of work:
The intake part is used directly at the moment of cutting, the calibrating part guides the tool and ensures its vertical position. Tail part is used to fasten the blade in a special holder.
Internal threads can be formed as follows:
- The pipe is clamped in an upright position.
- Tap the workpiece to be machined is lubricated.
- The tool is positioned vertically, and then rotated several times clockwise, and then rotated once counterclockwise.
Oil must be added from time to time at the time of operation. That allows the tool to run smoothly.
Threading the inside of the pipe
Adapters, elbows, couplings have internal threads, they are screwed on the pipe without reducing its inner passage. But if you think about making your own pipe fittings, you’ll need this skill.
In this case taps are used for threading (on the photo). This is a metal rod with a cutting part. Edges are made in separate segments, separated by a longitudinal groove to keep out swarf. The tap has a square shank, to which a screwdriver is fitted and rotated. The kit includes two taps, one for roughing and one for finishing.