Tapered hole rc 1. Holes for taper pipe threading. Tools for making internal threads
Making an internal thread is usually not difficult. But some features of using a tool and selecting holes for cutting metric threads exist.
Thread types
They differ in the main characteristics:
- diameter calculation system (inch, metric, others);
- number of visits (two-, three- or single-pass);
- profile shape (rectangular, trapezoidal, triangular, round);
- direction of rotation of the screw (left or right);
- placement on the part (internal or external);
- the shape of the part (cone or cylinder);
- purpose (running, fastening-sealing or fastening).
According to the listed signs, the following types are distinguished:
- cylindrical (MJ);
- metric and conical (M, MK);
- pipe (G, R);
- Edison round (E);
- trapezoidal (Tr);
- round for plumbing fixtures (Kp);
- thrust (S, S45);
- inch, including cylindrical and conical (BSW, UTS, NPT);
- oil grade.
Tools for making internal threads
To make an internal thread, you need a tap - a helical tool with sharp grooves. The rod may be in the form of a cone or a cylinder. The grooves run along and break the thread into sections called combs. It is the edges of the combs that are the working surfaces.
To make the groove clean, the metal is removed gradually, in layers. This requires one very long tool or set.
Single taps are also found on sale, they are more often used to fix stripped threads. To cut a new one, they buy a kit. Therefore, taps are usually sold in pairs: for roughing and for finishing work. The first cuts a shallow groove, the second cleans and deepens it. There are also three-pass tools. Thin, up to 3 millimeters taps are sold in twos, wider taps in threes. Three-way taps are inserted into the collars. The device of the knobs is different, but their size must match the size of the cutter.
In the set, the tools are distinguished by the risks applied on the tail end. If you look closely, you can notice the differences in shape:
- the first tap with heavily cut tooth tips, the outer diameter is slightly smaller than the other tools in the set;
- second tap with shorter pick segment, longer combs. Its diameter is slightly larger than that of the first;
- the third tap has full ridges of teeth, and its diameter must match the dimensions of the future thread.
Taps are divided into pipe taps (marked with a “G”) for threading inside a pipe and metric taps - more common.
The quality directly depends on the properties of the tap: it must be from good metal and sharp. Lubrication is used to extend the life of the tool and improve the quality of the thread. It usually takes 3-5 attempts to acquire a stable slicing skill.
cutting process
Before you start cutting, you should use drills to make a hole in the workpiece. The diameter of the hole from the drill must match internal dimension threads. When the size of the hole made by the drills is not chosen correctly, you can break the tool or the grooves will turn out to be of poor quality.
During cutting, part of the metal does not fall out with chips, but is pressed through the working surfaces of the tap, forming a groove profile on the workpiece. Given this feature, the size of the drill with which the hole for the thread is made is selected slightly less than the nominal diameter of the future thread.
For example, when cutting M5 (groove diameter is 5 mm), you should choose a drill for a hole of 4.2 mm. For cutting M4, the diameter of the drill should be 3.3 millimeters, and before working with the M6 tap, a hole is first made with a 5 mm drill. This indicator is calculated taking into account the thread pitch. The step can be calculated mathematically, but in practice they resort to correspondence tables, where for the M5 tap the step is 0.8, for M4 this figure is 0.7, for M6 - 1. Subtract the step indicator from the diameter and get the desired drill diameter. When working with brittle metals, such as cast iron, the drill diameter should be reduced by 0.1 mm compared to the size recommended in the table.
The formula for calculating the hole diameter when working with three-pass taps:
Up to \u003d Dm * 0.8;
where: Dm is the diameter of the tap.
| Type | Diameter | Step |
| M1 | 0,75 | 0,25 |
| M1.2 | 0,95 | 0,25 |
| 1,4 | 1,1 | 0,3 |
| 1,7 | 1,3 | 0,36 |
| 2,6 | 1,6 | 0,4 |
| 2,8 | 1,9 | 0,4 |
| M3 | 2,1 | 0,46 |
| M3 | 2,5 | 0,5 |
| M4 | 3,3 | 0,7 |
| M5 | 4,1 | 0,8 |
| M6 | 4,9 | 1 |
| M8 | 6,7 | 1,25 |
| M10 | 8,4 | 1,5 |
Table 1 Correspondence of thread diameters and preparatory holes
Before starting work, the tap is inserted into a square shank - a crank. Collars can be regular or with a ratchet. The carving is done carefully, the first pass is made with tap No. 1 to the end. Particular attention must be paid to the direction of movement: only clockwise, while some effort is necessary. It is carried out as follows: 1/2 turn in the direction alternates with 1/4 turn against the screw to break the chips.
| Thread in inches | External D, mm | Diameter, in mm | Pitch, mm |
| 1\8″ | 2,095 | 0,74 | 1,058 |
| 1\4″ | 6,35 | 4,72 | 1,27 |
| 3\16″ | 4,762 | 3,47 | 1,058 |
| 5\16″ | 7,938 | 6,13 | 1,411 |
| 7\16″ | 11,112 | 8,79 | 1,814 |
| 3\8″ | 9,525 | 7,49 | 1,588 |
Table 2. Hole diameters for inch threads
A couple of drops of lubricant make it much easier to work on blind threaded holes. Although engine oil is sometimes used as a lubricant, drying oil is optimal for working with steel. With aluminum alloys, it is preferable to use kerosene, alcohol or turpentine. Technical oil can also be used, but with less effect.
Homemade tap for aluminum alloys
To create internal threads in brass or light alloy parts, you can use homemade tool and drills from the usual set. Suitable calibrated steel wire. With the help of a die, an external thread is cut on it, after which the workpiece is hardened. After hardening, it is necessary to release the part to the color of ripe straw. The cutting edges are sharpened with a bar or sharpener, after clamping the part in a collet chuck.
Video on how to cut an internal thread:
It would seem that in the pipes of the complex? Connect and twist ... But, if you are not a plumber or an engineer with a specialized education, then questions will definitely arise for answers to which you will have to go where your eyes look. And they most likely look first on the Internet)
Earlier we talked about diameters metal pipes in this material. Today we will try to clarify the threaded connections of pipes for various purposes. We have tried not to clutter up the article with definitions. Basic terminology contains GOST 11708-82 which everyone can see for themselves.
Pipe cylindrical thread. GOST 6357 - 81
Direction: Left
Accuracy class: Class A (increased), Class B (normal)
Why in inches?
The inch size came to us from Western colleagues, since the requirements of the current in the post-Soviet space GOST and formulated on the basis of the thread BSW(British Standard Whitworth or Whitworth thread). Joseph Whitworth (1803 - 1887), a design engineer and inventor back in 1841, demonstrated the screw profile of the same name for detachable connections and positioned it as a universal, reliable and convenient standard.
This type of thread is used both in the pipes themselves and in the elements of pipe connections: locknuts, couplings, elbows, tees ( see picture above). In the section of the profile, we see an isosceles triangle with an angle of 55 degrees and roundings at the tops and bottoms of the contour, which are made for high tightness of the connection.
Threading is carried out on sizes up to 6”. All pipes bigger size to secure the connection and prevent rupture, they are fixed by welding.
Symbol in the international standard
International: G
Japan: PF
UK: BSPP
The letter G is indicated and the bore diameter (inner Ø) of the pipe in inches. The outer diameter of the thread itself is not present in the designation.
Example:
G 1/2- a pipe thread cylindrical external, internal Ø of a pipe 1/2 "". The outer diameter of the pipe will be 20.995 mm, the number of steps for a length of 25.4 mm will be 14.
The accuracy class (A, B) and the direction of the turns (LH) can also be indicated.
For example:
G 1 ½ - B- cylindrical pipe thread, internal Ø 1 ½ inches, accuracy class B.
G1 ½ LH-B- cylindrical pipe thread, internal Ø 1 ½ inches, accuracy class B, left.
The make-up length is indicated last in mm: G 1 ½ -B-40.
For an internal cylindrical pipe thread, only the Ø of the pipe for which the hole is intended will be indicated.
Parallel pipe thread size chart
| Thread size |
Thread pitch, mm |
Threads per inch |
Thread diameters |
|||
How to determine the pitch of an inch thread
I give you a picture from the English-speaking Internet, which clearly demonstrates the technique. Pipe threads are characterized not by the size between the tops of the profile, but by the number of turns per 1 inch along the axis of the thread. To help the usual tape measure or ruler. We apply, measure one inch (25.4 mm) and visually count the number of steps.
In the picture with an example ( see above) threads - from English it is literally "thread threads". In this case, there are 18 of them. one inch.
It's even easier if you have an inch thread gauge lying around in your toolbox. It is very convenient to carry out measurements, but it must be remembered that inch threads may differ in the apex angle of 55 ° and 60 °.
Tapered pipe threads
drawing pipe taper threads
Tapered pipe thread GOST 6211-81 (1st standard size)
Parameter unit: Inch
Corresponds to the rounded profile of a cylindrical pipe thread with an angle of 55°. Cm. top part (I) of the three-dimensional image "picture of pipe taper threads".
Symbol
International: R
Japan: PT
UK: BSPT
The letter R and the nominal diameter Dy are indicated. The designation R means appearance threads, Rc internal, Rp internal cylindrical. By analogy with cylindrical pipe threads, LH is used for left-hand threads.
Examples:
R1½- external pipe conical thread, nominal diameter Dy = 1 ½ inches.
R1 ½ LH- external pipe taper thread, nominal diameter Dy = 1 ½ inches, left hand.
Conical inch thread GOST 6111 - 52 (2nd standard size)
Parameter unit: Inch
Has a profile angle of 60°. Cm. lower part (II) of the three-dimensional image "picture of pipe conical threads". It is used in pipelines (fuel, water, air) of machines and machine tools with relatively low pressure. The use of this type of connection assumes tightness and thread locking without additional special means(linen threads, yarn with red lead).
Symbol
Example: K ½ GOST 6111 - 52
It stands for: inch conical thread with an outer and inner diameter in the main plane approximately equal to the outer and inner Ø of a cylindrical pipe thread G ½
Table of the main parameters of the conical inch thread
| Thread size designation (d, inches) | Number of threads per 1" n | Thread pitch S, mm | Thread length, mm | External thread diameter in the main plane d, mm | |
| Working l1 | From the end of the pipe to the main plane l2 | ||||
| 1/16 | 27 | 0,941 | 6,5 | 4,064 | 7,895 |
| 1/8 | 27 | 0,941 | 7,0 | 4,572 | 10,272 |
| 1/4 | 18 | 1,411 | 9,5 | 5,080 | 13,572 |
| 3/8 | 18 | 1,411 | 10,5 | 6,096 | 17,055 |
| 1/2 | 14 | 1,814 | 13,5 | 8,128 | 21 793 |
| 3/4 | 14 | 1,814 | 14,0 | 8,611 | 26,568 |
| 1 | 11 1/2 | 2,209 | 17,5 | 10,160 | 33,228 |
| 1 1/4 | 11 1/2 | 2,209 | 18,0 | 10,668 | 41,985 |
| 1 1/2 | 11 1/2 | 2,209 | 18,5 | 10,668 | 48,054 |
| 2 | 11 1/2 | 2,209 | 19,0 | 11,074 | 60,092 |
Metric taper thread. GOST 25229 - 82
Parameter unit: mm
Manufactured on surfaces with a taper of 1:16
It is used when connecting pipelines. The angle at the top of the coil is 60°. The main plane is offset relative to the end ( see pic above).
Symbol
The letters MK are followed by an indication of the diameter in the main plane and the thread pitch in mm: MK 30x2
Metric Taper Thread Size Chart
| Thread diameter d for a row | P step | Thread diameter in base plane | ||||||
| 1 | 2 | d=D | d2=D2 | d1=D1 | l | l1 | l2 | |
| 6 | --- | 1 | 6,000 | 5,350 | 4,917 | 8 | 2,5 | 3 |
| 8 | --- | 8,000 | 7,350 | 6,917 | ||||
| 10 | --- | 10,000 | 9,350 | 8,917 | ||||
| 12 | --- | 1,5 | 12,000 | 11,026 | 10,376 | 11 | 3,5 | 4 |
| --- | 14 | 14,000 | 13,026 | 12,376 | ||||
| 16 | --- | 16,000 | 15,026 | 14,376 | ||||
| --- | 18 | 18,000 | 17,026 | 16,376 | ||||
| 20 | --- | 20,000 | 19,026 | 18,376 | ||||
| --- | 22 | 22,000 | 21,026 | 20,376 | ||||
| 24 | --- | 24,000 | 23,026 | 22,376 | ||||
| --- | 27 | 2 | 27,000 | 25,701 | 24,835 | 16 | 5 | 6 |
| 30 | --- | 30,000 | 28,701 | 27,835 | ||||
| --- | 33 | 33,000 | 31,701 | 30,835 | ||||
| 36 | --- | 36,000 | 34,701 | 33,835 | ||||
Characteristics of cylindrical pipe / inch threads relative to metric
The main characteristics of "inch" and "pipe" cylindrical threads in relation to the "metric" thread for the main dimensions.
|
Nominal thread diameter in dm |
Inch thread |
Pipe thread |
||||
|
outer diameter, in mm |
number of threads per 1" |
outer diameter, in mm |
number of threads per 1" |
|||
Despite the fact that the cutting of internal threads is not a complex technological operation, there are some features of the preparation for this procedure. So, you should accurately determine the dimensions of the preparatory hole for threading, as well as choose the right tool, for which special tables of drill diameters for threading are used. For each type of thread, you must use the appropriate tool and calculate the diameter of the preparation hole.
Varieties and parameters of thread
The parameters by which the thread is divided into Various types, are:
- diameter units (metric, inch, etc.);
- number of thread entries (one-, two- or three-way);
- the shape in which the profile elements are made (triangular, rectangular, round, trapezoidal);
- the direction of the rise of the turns (right or left);
- location on the product (external or internal);
- surface shape (cylindrical or conical);
- purpose (fixing, fixing and sealing, running).
Depending on the above parameters, the following types of thread are distinguished:
- cylindrical, which is indicated by the letters MJ;
- metric and conical, denoted respectively by M and MK;
- pipe, for which the letters G and R are used;
- with a round profile, named after Edison and marked with the letter E;
- trapezoidal, designated Tr;
- round, used for the installation of sanitary fittings, - Kr;
- persistent and persistent reinforced, marked as S and S45, respectively;
- inch thread, which can also be cylindrical and conical - BSW, UTS, NPT;
- used to connect pipes installed in oil wells.
Application of the tap
Before you start threading, you need to determine the diameter of the preparatory hole and drill it. To facilitate this task, the corresponding GOST was developed, which contains tables that allow you to accurately determine the diameter of the threaded hole. This information makes it easy to choose the size of the drill.
To cut metric threads on the inner walls of a hole made with a drill, a tap is used - a helical tool with cutting grooves, made in the form of a rod, which can have a cylindrical or conical shape. On its lateral surface there are special grooves located along its axis and dividing the working part into separate segments, which are called combs. The sharp edges of the combs are precisely the working surfaces of the tap.
In order for the turns of the internal thread to turn out to be clean and neat, and its geometric parameters to correspond to the required values, it must be cut gradually, by gradually removing thin layers of metal from the surface being machined. That is why, for this purpose, either taps are used, the working part of which is divided along the length into sections with different geometric parameters, or sets of such tools. Single taps, the working part of which has the same geometric parameters along its entire length, are needed in cases where it is necessary to restore the parameters of an existing thread.
The minimum set, with which you can perform the processing of threaded holes with sufficient quality, is a set consisting of two taps - roughing and finishing. The first cuts off a thin layer of metal from the walls of the hole for cutting metric threads and forms a shallow groove on them, the second not only deepens the formed groove, but also cleans it.
Combination two-pass taps or two-tool sets are used for threading small diameter holes (up to 3 mm). For drilling holes metric thread larger diameters, use a combination 3-pass tool or a set of 3 taps.
To manipulate the tap, a special device is used - a crank. The main parameter of such devices, which can have different designs, is the size of the mounting hole, which must exactly match the size of the tool shank.
When using a set of three taps that differ both in their design and geometric parameters, the sequence of their application should be strictly observed. You can distinguish them from each other both by special risks applied to the shanks, and by design features.
- The tap, with which the hole for cutting metric threads is processed first of all, is distinguished by the smallest diameter among all tools in the set and cutting teeth, top part which are heavily cut off.
- The second tap has a shorter chamfer and longer combs. Its working diameter occupies an intermediate value between the diameters of other tools from the set.
- The third tap, with which the hole for cutting metric threads is finished last, is characterized by full ridges of cutting teeth and a diameter that must exactly match the size of the thread being formed.
Taps are used primarily for threading metric threads. Much less frequently than metric taps, taps designed for processing inner walls pipes. They are called pipe pipes in accordance with their purpose, and they can be distinguished by the letter G present in their marking.
Thread cutting technology
As mentioned above, before starting work, it is necessary to drill a hole, the diameter of which must exactly fit the thread of a certain size. It should be borne in mind: if the diameters of the holes intended for cutting metric threads are chosen incorrectly, this can lead not only to its poor quality, but also to breakage of the tap.
Taking into account the fact that the tap, forming threaded grooves, not only cuts off the metal, but also pushes it through, the diameter of the drill for threading should be somewhat smaller than its nominal diameter. For example, a drill for threading M3 should have a diameter of 2.5 mm, for M4 - 3.3 mm, for M5 you should choose a drill with a diameter of 4.2 mm, for M6 thread - 5 mm, M8 - 6.7 mm, M10 - 8.5 mm, and for M12 - 10.2.
Table 1. Main hole diameters for metric threads
All diameters of drills for GOST thread are given in special tables. Such tables indicate the diameters of drills for making threads with both standard and reduced pitch, while it should be borne in mind that holes of different diameters are drilled for these purposes. In addition, if threads are cut in brittle metals (such as cast iron), the diameter of the tap drill obtained from the table must be reduced by one tenth of a millimeter.
You can familiarize yourself with the provisions of GOST governing the cutting of metric threads by downloading the document in pdf format from the link below.
The diameters of drills for metric threads can be calculated independently. From the diameter of the thread to be cut, subtract the value of its pitch. The thread pitch itself, the size of which is used when performing such calculations, can be found in special correspondence tables. In order to determine what diameter the hole must be made with a drill if a three-start tap is used for threading, the following formula must be used:
D o \u003d D m x 0.8, where:
Before- this is the diameter of the hole to be made with a drill,
D m- the diameter of the tap with which the drilled element will be processed.
Download full version
GOST 21350-75
Group G13
STATE STANDARD OF THE UNION OF THE SSR
HOLES FOR TAPERED PIPE THREADING
Diameters
Holes for threading pipe taper screw thread.
Diameters
The validity period is set from 01.01.77
______________________________
* Expiry date removed
Decree of the State Standard of the USSR
No. 2403 dated 06/29/84. (IUS N 11, 1984).
DEVELOPED, INTRODUCED AND PREPARED FOR APPROVAL by the All-Union Research Institute for Normalization in Mechanical Engineering (VNIINMASH)
And about. director Gerasimov N.N.
Head of the theme and performer Zaroslova M.P.
APPROVED AND INTRODUCED BY Decree of the State Committee for Standards of the Council of Ministers of the USSR dated December 12, 1975 N 3877
REPLACE MH 5389-64
1. This standard establishes the diameters of holes for cutting pipe taper threads in accordance with GOST 6211-69 in steel products in accordance with GOST 380-71, GOST 4543-71, GOST 1050-74, GOST 5058-75 and GOST 5632-72 (except for alloys on nickel-based) and copper according to GOST 859-66.
2. Hole diameters with taper reaming and their limit deviations must correspond to those indicated in Fig. 1 and in Table 1.
Table 1
|
Hole diameter |
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|
Number of threads per |
drilling depth |
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|
Prev off |
Prev off |
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Note. For threads with a nominal size greater than the nominal diameters of the holes and their maximum deviations must be equal to those established by GOST 6211-69 for the inner diameter of the thread.
3. The diameters of the holes without reaming into a cone and their limiting deviations must correspond to those indicated in Fig. 2 and in Table 2.
table 2
|
Nominal thread size in inches |
Number of threads per |
Hole diameter |
drilling depth |
|||
|
Previous off |
||||||
4. It is allowed to use holes of other diameters obtained on the basis of experimental data for taper pipe threading.
5. Drill diameters for tapping holes are listed in the recommended application.
Drill diameters for taper pipe threads
|
Nominal thread size in inches |
Number of threads per |
Hole drill diameter |
||||
|
with cone reaming |
without cone reaming |
|||||
| gost_2135075_imashru.rar To download files, please register. If you already have Account on the Mechanical Engineering Resource site, then you need to log in to the site. |
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To cut an internal thread on a part, you must first drill a hole. Its size is not equal to the diameter of the thread, but should be slightly smaller. You can find the diameter of the drill for a thread in a special table, but for this you also need to know the type of thread.
Main settings
- diameter (D);
- step (P) - the distance from one turn to another.
They are determined by GOST 1973257-73. A large step is considered normal, but several smaller ones correspond to it. A small pitch is used when applied to thin-walled products (thin-walled pipes). They also make a small turn if the applied thread is a way to adjust any parameters. Also, a small step between the turns is made to increase the tightness of the connection and to overcome the phenomenon of self-unscrewing of the part. In other cases, a standard (large) step is cut.
There are many types of threads, since each has its own formation characteristics, the diameter of the threaded hole in each case is different. All of them are spelled out in GOSTs, but most often they use triangular metric and conical metric threads. We will talk about them further.
We usually see triangular threads on bolts and other similar fasteners, conical threads on most plumbing products that require a detachable connection.
fixtures
For threading with your own hands, small devices are used:
All these devices are made of alloys, which are characterized by increased strength and resistance to abrasion. Grooves and grooves are applied to their surface, with the help of which their mirror image is obtained on the workpiece.
Any tap or die is marked - they have an inscription indicating the type of thread that this device cuts - diameter and pitch. They are inserted into holders - knobs and die holders - fixed there with screws. Clamping the threading tool in the holder, put it on / insert it into the place where you want to make a detachable connection. By scrolling the device, turns are formed. It depends on how correctly the device is set at the beginning of work whether the turns “lie down” evenly. Therefore, make the first turns trying to keep the structure even, avoiding shifts and distortions. After a few turns have been made, the process will become easier.
You can cut threads of small or medium diameter manually. Complex types (two- and three-way) or working with large diameters by hand is not possible - too much effort is required. For these purposes, special mechanized equipment is used - on lathes with taps and dies attached to them.
How to cut correctly
You can thread almost any metal and their alloys - steel, copper, aluminum, cast iron, bronze, brass, etc. It is not recommended to make it on a red-hot iron - it is too rigid, it will crumble during operation and it will not be possible to achieve high-quality turns, which means that the connection will be unreliable.
Tool for the job
Training
It is necessary to work on clean metal - remove rust, sand and other contaminants. Then the place where the thread will be applied must be lubricated (except for cast iron and bronze - they must be worked “dry”). There is a special emulsion for lubrication, but if it is not available, soaked soap can be used. You can also use other lubricants:
You can often hear advice to use machine or mineral oil or even lard when threading. They work well, but experts say that it is better not to do this - the chips will stick to a viscous substance, which will lead to rapid wear of the tap or die.
Slicing process
When cutting an external thread, the die is placed strictly perpendicular to the surface of the pipe or rod. During operation, it should not wag, otherwise the turns will turn out to be uneven and the connection will be ugly and unreliable. The first turns are especially important. It depends on how they “lie down” whether the connection will then be skewed.
By applying an internal thread, the part is fixed motionless. If it is a small piece, it can be clamped in a vise. If the plate is large, ensure its immobility by available methods, for example, by fixing it with bars. M
The tap is inserted into the hole so that its axis is parallel to the axis of the hole. With a little effort, little by little, they begin to twist in a given direction. As soon as you feel that the resistance has increased, unscrew the tap back and clean it of chips. After cleaning, the process continues.
The process of slicing in a photo
When cutting threads in a blind hole, its depth should be slightly more than required - this excess should include the tip of the tap. If this is structurally impossible, the tip is cut off from the tap. At the same time, it is not suitable for further operation, but there is no other way out.
In order for the turns to turn out to be of high quality, two taps or dies are used - roughing and finishing. The first pass is a rough pass, the second is a finish pass. There are also combined threading devices. They allow you to do everything in one pass.
Another practical advice: so that the chips do not fall into the working area, when cutting, make one full turn clockwise, then half a turn counterclockwise. After that, the tool is returned to the place where it stopped and again make one revolution. So continue to the required length.
Tapping drill diameter selection tables
When making an internal thread, a hole is pre-drilled under it. It is not equal to the diameter of the thread, since during cutting, part of the material is not removed in the form of chips, but is squeezed out, increasing the size of the protrusions. Therefore, before applying, it is necessary to select the diameter of the drill for the thread. This can be done in tables. They are for each type of thread, but we will give the most popular ones - metric, inch, pipe.
| Metric thread | Inch thread | Pipe thread | |||||
|---|---|---|---|---|---|---|---|
| Thread diameter, inches | Thread pitch, mm | Drill diameter, mm | Thread diameter, inches | Thread pitch, mm | Drill diameter, mm | Thread diameter, inches | Thread hole diameter, mm |
| M1 | 0.25 | 0,75 | 3/16 | 1.058 | 3.6 | 1/8 | 8,8 |
| M1.4 | 0,3 | 1,1 | 1/4 | 1.270 | 5.0 | 1/4 | 11,7 |
| M1.7 | 0,35 | 1,3 | 5/16 | 1.411 | 6.4 | 3/8 | 15,2 |
| M2 | 0,4 | 1,6 | 3/8 | 1.588 | 7.8 | 1/2 | 18,6 |
| M2.6 | 0,4 | 2,2 | 7/16 | 1.814 | 9.2 | 3/4 | 24,3 |
| M3 | 0,5 | 2,5 | 1/2 | 2,117 | 10,4 | 1 | 30,5 |
| M3.5 | 0,6 | 2,8 | 9/16 | 2,117 | 11,8 | - | - |
| M4 | 0,7 | 3,3 | 5/8 | 2,309 | 13,3 | 11/4 | 39,2 |
| M5 | 0,8 | 4,2 | 3/4 | 2,540 | 16,3 | 13/8 | 41,6 |
| M6 | 1,0 | 5,0 | 7/8 | 2,822 | 19,1 | 11/2 | 45,1 |
| M8 | 1,25 | 6,75 | 1 | 3,175 | 21,3 | - | - |
| M10 | 1,5 | 8,5 | 11/8 | 3,629 | 24,6 | - | - |
| M12 | 1,75 | 10,25 | 11/4 | 3,629 | 27,6 | - | - |
| M14 | 2,0 | 11,5 | 13/8 | 4,233 | 30,1 | - | - |
| M16 | 2,0 | 13,5 | - | - | - | - | - |
| M18 | 2,5 | 15,25 | 11/2 | 4,33 | 33,2 | - | - |
| M20 | 2,5 | 17,25 | 15/8 | 6,080 | 35,2 | - | - |
| M22 | 2,6 | 19 | 13/4 | 5,080 | 34,0 | - | - |
| M24 | 3,0 | 20,5 | 17/8 | 5,644 | 41,1 | - | - |
Once again, we draw your attention to the fact that the diameter of the drill for threading is given for large (standard threads).
Table of rod diameters for external thread
When working in an external thread, the situation is very similar - part of the metal is squeezed out, and not cut off. Therefore, the diameter of the rod or pipe on which the thread is applied should be slightly smaller. How accurate - see the table below.
| Thread diameter, mm | 5,0 | 6 | 8 | 10 | 12 | 16 | 20 | 24 |
|---|---|---|---|---|---|---|---|---|
| Rod diameter, mm | 4,92 | 5,92 | 7,9 | 9,9 | 11,88 | 15,88 | 19,86 | 23,86 |