3 8 inches which diameter. Translation of numbers from one number system to another online. Main parameters of inch thread

This article will consider such concepts associated with a threaded compound as metric and inch thread. To understand the subtleties associated with the threaded compound, it is necessary to consider the following concepts:

Conical and cylindrical thread

Stem itself with applied to him conical carvings It is a cone. And according to international RulesThe cone should be 1 to 16, that is, for every 16 units of measurement (millimeters or inches) with an increase in distance from the starting point, the diameter increases by 1 corresponding unit of measurement. It turns out that the axis around which the carving is applied and the conditional direct, conducted from the beginning of the thread before it is completed along the shortest path - are not parallel, but are one to each other at a certain angle. If you explain even easier, then if we have a length threaded compound It was 16 centimeters, and the diameter of the rod in its starting point would be 4 centimeters, then at a point where the thread ends, the diameter would have already 5 centimeters.

Stem S. cylindrical thread It is a cylinder, respectively, there is no taper.

Thread (metric and inches)

The thread step can be large (or basic) and small. Under pitch thread It is understood to the distance between the turns of the thread from the top of the turn to the top of the next turn. It can be measured even with the help of a caliper (although there are special meters). This is done as follows - the distance between several vertices of turns is measured, and then the resulting number is divided by their number. You can check the measurement accuracy on the table for the appropriate step.

Pipe carving cylindrical according to GOST 6357-52
Designation	Number N. on 1 "	Pitch thread S, mm.	Outside diameter Threads, mm.	Middle diameter Threads, mm.	Inner diameter Threads, mm.
G1 / 8 "	28	0,907	9,729	9,148	8,567
G1 / 4 "	19	1,337	13,158	12,302	11,446
G3 / 8 "	19	1,337	16,663	15,807	14,951
G1 / 2 "	14	1,814	20,956	19,754	18,632
G3 / 4 "	14	1,814	26,442	25,281	24,119
G7 / 8 "	14	1,814	30,202	29,040	27,878
G1 "	11	2,309	33,250	31,771	30,292

Nominal diameter of thread

Marking is usually present nominal diameterfor which in most cases is accepted outside diameter Threads. If the carving is metric, then for measurement you can use a regular caliper with scales in millimeters. Also diameter, like a thread step, you can see special tables.

Metric and inch thread on examples

Metric carving - It has the designation of the main parameters in millimeters. For example, consider an angular fitting with external cylindrical carvings. EPL 6-GM5. In this case, EPL suggests that the fitting of the corner, 6-ka is 6 mm - external diameter pipe connected to fitting. Liter "G" in its marking reports that the carving is cylindrical. "M" indicates that the carving is metric, and the figure "5" indicates the nominal diameter of a thread equal to 5 millimeters. Fittings (from those on sale) with a literary "G" are also equipped with rubber sealing ringand therefore do not require fum-ribbons. The thread step in this case is 0.8 millimeters.

Main settings inch thread, respectively, the name is indicated in inches. It can be a thread on 1/8, 1/4, 3/8 and 1/2 inches, etc. For example, take fitting EPKB 8-02. EPKB is a type of fitting (in this case a splitter). Thread conical, although there is no reference with the help of the Litera "R", which would be more competent. 8-ka - suggests that the external diameter of the connected tube is 8 millimeters. A 02 - that connecting carving on 1/4 inches fitting. According to the table, the thread step is 1.337 mm. The nominal diameter of the thread is 13,157 mm.

Conical and cylindrical thread profiles coincide, which allows you to pursue fittings with conical Threads and cylindrical.

inches	mm.	inches	mm.	inches	mm.	inches	mm.	inches	mm.
-	-	1	25,4	2	50,8	3	76,2	4	101,6
1/8	3,2	1 1/8	28,6	2 1/8	54,0	3 1/8	79,4	4 1/8	104,8
1/4	6,4	1 1/4	31,8	2 1/4	57,2	3 1/4	82,6	4 1/4	108,8
3/8	9,5	1 3/8	34,9	2 3/8	60,3	3 3/8	85,7	4 3/8	111,1
1/2	12,7	1 1/2	38,1	2 1/2	63,5	3 1/2	88,9	4 1/2	114,3
5/8	15,9	1 5/8	41,3	2 5/8	66,7	3 5/8	92,1	4 5/8	117,5
3/4	19,0	1 3/4	44,4	2 3/4	69,8	3 3/4	95,2	4 3/4	120,6
7/8	22,2	1 7/8	47,6	2 7/8	73,0	3 7/8	98,4	4 7/8	123,8

Parameters of inch threads

The outer diameter of the pipe connected		SAE thread rating	Nominal Threads UNF.	Outer thread diameter, mm	The average diameter of the thread, mm	Pitch thread
mM.	inch	SAE thread rating	Nominal Threads UNF.	Outer thread diameter, mm	The average diameter of the thread, mm	mM.	thread / inch
6	1/4""""	1/4""""	7/16""""-20	11,079	9,738	1,27	20
8	5/16""""	5/16""""	5/8""""-18	15,839	14,348	1,411	18
10	3/8""""	3/8""""	5/8""""-18	15,839	14,348	1,411	18
12	1/2""""	1/2""""	3/4""""-16	19,012	17,33	1,588	16
16	5/8""""	5/8""""	7/8""""-14	22,184	20,262	1,814	14
18	3/4""""	3/4""""	1""""-14	25,357	23,437	1,814	14
18	3/4""""	---	1""""1/16-14	26,947	25,024	1,814	14
20	7/8""""	---	1""""1/8-12	28,529	26,284	2,117	12
22	7/8""""	7/8""""	1""""1/4-12	31,704	29,459	2,117	12
22	7/8""""	---	1""""3/8-12	34,877	32,634	2,117	12
25	1""""	1""""	1""""1/2-12	38,052	35,809	2,117	12

Copper veins, wires and cables

Section of conductive veins, mm	Copper veins, wires and cables
	Voltage, 220 V		Voltage, 380 V
	Talk, A.	power, kWt	Talk, A.	power, kWt
1,5	19	4,1	16	10,5
2,5	27	5,9	25	16,5
4	38	8,3	30	19,8
6	46	10,1	40	26,4
10	70	15,4	50	33,0
16	85	18,7	75	49,5
25	115	25,3	90	59,4
35	135	29,7	115	75,9
50	175	38,5	145	95,7
70	215	47,3	180	118,8
95	260	57,2	220	145,2
120	300	66,0	260	171,6

Aluminum veins, wires and cables

The cross section of the current veins, mm	Aluminum veins, wires and cables
	Voltage, 220 V		Voltage, 380 V
	Talk, A.	power, kWt	Talk, A.	power, kWt
1,5	19	4,1	16	10,5
2,5	27	5,9	25	16,5
4	38	8,3	30	19,8
6	46	10,1	40	26,4
10	70	15,4	50	33,0
16	85	18,7	75	49,5
25	115	25,3	90	59,4
35	135	29,7	115	75,9
50	175	38,5	145	95,7
70	215	47,3	180	118,8
95	260	57,2	220	145,2
120	300	66,0	260	171,6

Dimensions of inch thread


	Thread diameter in mm			Thread step in mm	Number of threads per 1 "
	Outdoor D.	Middle D.	Inner D.	Thread step in mm	Number of threads per 1 "
3/16	4,762	4,085	3,408	1,058	24
1/4	6,350	5,537	4,724	1,270	20
5/16	7,938	7,034	6,131	1,411	18
3/8	9,525	8,509	7,492	1,588	16
1/2	12,700	11,345	9,989	2,117	12
5,8	15,875	14,397	12,918	2,309	11
3/4	19,05	17,424	15,798	2,540	10
7/8	22,225	20,418	18,611	2,822	9
1	25,400	23,367	21,334	3,175	8
1 1/8	28,575	26,252	23,929	3,629	7
1 1/4	31,750	29,427	27,104	3,629	7
1 1/2	38,100	35,39	32,679	4,233	6
1 3/4	44,450	41,198	37,945	5,080	5
2	50,800	47,186	43,572	5,644	4 1/2

Nominal thread diameter in inches
	Thread diameter in mm			Thread step in mm	Number of threads per 1 "
	Outdoor D.	Middle D.	Inner D.	Thread step in mm	Number of threads per 1 "
1/8	9,729	9,148	8,567	0,907	28
1/4	13,158	12,302	11,446	1,337	19
3/8	16,663	15,807	14,951	1,337	19
1/2	20,956	19,794	18,632	1,814	14
5/8	22,912	21,750	20,588	1,814	14
3/4	26,442	25,281	24,119	1,814	14
7/8	30,202	29,040	27,878	1,814	14
1	33,250	31,771	30.293	2,309	11
1 1/8	37,898	36,420	34,941	2,309	11
1 1/4	41,912	40,433	38,954	2,309	11
1 3/8	44,325	32,846	41,367	2,309	11
1 1/2	47,805	46,326	44,847	2,309	11
1 3/4	53,748	52,270	50,791	2,309	11
2	59,616	58,137	56,659	2,309	11

Table of translation units

Translation of energy units	Translation of pressure units
1 J \u003d 0.24 Cal	1 Pa \u003d 1 n / m * m
1 kJ \u003d 0.28 W * h	1 Pa \u003d 0.102 kgf / m * m
1 W \u003d 1 J / s	1 atm \u003d 0,101 MPa \u003d 1.013 bar
1 Cal \u003d 4.2 J	1 bar \u003d 100 kPa \u003d 0,987 atm
1 kcal / h \u003d 1,163 W	1 psi \u003d 0,06895 bar \u003d 0,06805 atm

Sizes Translation Tables: Just and fast

The process of selecting the necessary sizes of the threaded section, cables and pipes often causes a variety of time. In addition to choosing suitable dimensions, taking into account the equipment parameters, the customer has to independently translate data into suitable units of measurement. Such a process is turning to be significant temporary costs.

We simplify this task, as we suggest you to use the ready-made translation tables. On the page of our site you will find tables that will help you easily choose the necessary threads of inch pipes, copper and aluminum wires and cables. Also, you can use the table of translation in the metric, thereby accurately calculate the necessary section sizes.

Unfortunately, most equipment manufacturers leave the customer one to one with the execution of calculations. Therefore, a person has to independently search for the translation table on the internet for the purpose of selection optimal sizes The cross sections of the wires and diameters of pipes.

We value the time of our customers, giving everyone the opportunity to use ready-made solutions. In our tables translated standard dimensions from inches in millimeters.

On this page, you will also find the translations of the main energy units and pressure units, therefore, can choose correctly refrigeration equipment, given the individual conditions of placement and modes of operation of the aggregates.

With the help of this online calculator You can translate integers and fractional numbers from one number system to another. Given detailed solution With explanations. To translate, enter the original number, set the source number system base, set the base of the number system to which you want to translate the number and click on the "Translate" button. Theoretical part and numerical examples see below.

The result is already received!

Translation of whole and fractional numbers from one number system to any other - theory, examples and solutions

There are positional and not positional number systems. Arabic number system that we use everyday life, It is a positional, and Roman - no. In positional surgery systems, the position of the number uniquely determines the value of the number. Consider this on the example of the number 6372 in a decimal number system. Number this number on the right left since scratch:

Then the number 6372 can be represented as follows:

6372 \u003d 6000 + 300 + 70 + 2 \u003d 6 · 10 3 + 3 · 10 2 + 7 · 10 1 + 2 · 10 0.

The number 10 defines the number system (in this case it is 10). As degrees, the positions of the number of this number are taken.

Consider real decimal number 1287.923. Number it starting from scratch the position of the number from the decimal point to the left and right:

Then the number 1287.923 can be represented as:

1287.923 \u003d 1000 + 200 + 80 + 7 + 0.9 + 0.02 + 0.003 \u003d 1 · 10 3 + 2 · 10 2 + 8 · 10 1 + 7 · 10 0 + 9 · 10 -1 + 2 · 10 -2 + 3 · 10 -3.

IN general The formula can be represented as follows:

C n · s. N + C N-1 · s. N-1 + ... + C 1 · s. 1 + C 0 · s 0 + d -1 · s -1 + d -2 · s -2 + ... + d -k · s -k

where c n is a number in position n., D -k - fractional number in position (-K), s. - Number system.

A few words about the number systems. The number in the decimal number system consists of a plurality of numbers (0.1,2,3,4,5,6,7,8,9), in an octaous number system - from a plurality of numbers (0.1, 2,3,4,5,6,7), in a binary number system - from a plurality of numbers (0.1), in a hexadecimal number system - from a plurality of numbers (0,1,2,3,4,5,6, 7,8,9, A, B, C, D, E, F), where A, B, C, D, E, F correspond to the number 10,11,12,13,14,15. In Table Table.1 Presented numbers B. different systems Note.

Table 1
Notation
10	2	8	16
0	0	0	0
1	1	1	1
2	10	2	2
3	11	3	3
4	100	4	4
5	101	5	5
6	110	6	6
7	111	7	7
8	1000	10	8
9	1001	11	9
10	1010	12	A.
11	1011	13	B.
12	1100	14	C.
13	1101	15	D.
14	1110	16	E.
15	1111	17	F.

Translation of numbers from one number system to another

To transfer numbers from one number system to another, the easiest way to first translate the number to the decimal number system, and then, from decimal system Number translate to the desired number system.

Translation of numbers from any number system in a decimal number system

Using formula (1), you can translate numbers from any number system to a decimal number system.

Example 1. Translate the number 1011101.001 from the binary number system (SS) in a decimal SS. Decision:

1 · 2 6 +0 · 2 5 + 1 · 2 4 + 1 · 2 3 + 1 · 2 2 + 0 · 2 1 + 1 · 2 0 + 0 · 2 -1 + 0 · 2 -2 + 1 · 2 -3 \u003d 64 + 16 + 8 + 4 + 1 + 1/8 \u003d 93.125

Example2. Translate the number 1011101.001 from the octaous number system (SS) in a decimal SS. Decision:

Example 3 . Translate the number AB572.CDF from a hexadecimal number system in a decimal SS. Decision:

Here A. - per 10, B. - by 11, C.- at 12, F. - by 15.

Translation of numbers from a decimal number system to another number system

To transfer numbers from a decimal numbering system to another number system, it is necessary to translate separately by the integer part of the number and fractional part of the number.

An integer part of the number is translated from a decimal SS to another number system - a sequential division of a whole part of the number on the base of the number system (for a binary CC - by 2, for an 8-character SS - by 8, for 16-smoke-16, etc. ) Before getting a whole residue, less than the base of the SS.

Example 4 . We translate the number 159 of the decimal SS into the binary SS:

159	2
158	79	2
1	78	39	2
	1	38	19	2
		1	18	9	2
			1	8	4	2
				1	4	2	2
					0	2	1
						0

As can be seen from fig. 1, the number 159 during division by 2 gives the private 79 and the residue 1. Next, the number 79 during division by 2 gives Private 39 and the residue 1, etc. As a result, by building a number from the balances of divisions (right to left) we get a number in binary ss: 10011111 . Consequently, you can write:

159 10 =10011111 2 .

Example 5 . We translate the number 615 of the decimal SS into the octal SS.

615	8
608	76	8
7	72	9	8
	4	8	1
		1

When the number from the decimal SS in the octal SS, it is necessary to sequentially divide the number on 8 until the whole residue is less than 8. As a result, building a number from the balances of division (right to left), we get a number in the octane SS: 1147 (See Fig. 2). Consequently, you can write:

615 10 =1147 8 .

Example 6 . We transfer the number 19673 from the decimal number system to hexadecimal SS.

19673	16
19664	1229	16
9	1216	76	16
	13	64	4
		12

As can be seen from Fig.

For the translation of the right decimal fractions (real number with a zero integer) into the number system with the base S, a given number is needed to multiply on s until it turns out a clean zero in the fractional part, or we will not get the required number of discharges. If you get a number with a whole part, different from zero, then this whole part does not take into account (they are consistently enrolled in the result).

Consider the foregoing on the examples.

Example 7 . We transfer the number 0.214 from the decimal number system to binary SS.

		0.214
	x.	2
0		0.428
	x.	2
0		0.856
	x.	2
1		0.712
	x.	2
1		0.424
	x.	2
0		0.848
	x.	2
1		0.696
	x.	2
1		0.392

As can be seen from Fig. 4, the number 0.214 is multiplied by 2. If the multiplication is obtained with a whole part, different from zero, then the integer part is written separately (to the left of the number), and the number is written to the zero integer. If, when multiplying, a number with a zero integer is obtained, then zero is written to the left. The multiplication process continues until the fractional part does not get pure zero or do not get the required number of discharges. Recording fatty numbers (Fig. 4) from top to bottom We obtain the desired number in the binary number system: 0. 0011011 .

Consequently, you can write:

0.214 10 =0.0011011 2 .

Example 8 . We translate the number 0.125 from the decimal number system to binary SS.

		0.125
	x.	2
0		0.25
	x.	2
0		0.5
	x.	2
1		0.0

To bring the number of 0.125 of the decimal SS into a binary, this number is multiplied by 2. In the third stage it turned out 0. Therefore, the following result turned out:

0.125 10 =0.001 2 .

Example 9 . We translate the number 0.214 from the decimal number system to hexadecimal SS.

		0.214
	x.	16
3		0.424
	x.	16
6		0.784
	x.	16
12		0.544
	x.	16
8		0.704
	x.	16
11		0.264
	x.	16
4		0.224

Following examples 4 and 5, we obtain numbers 3, 6, 12, 8, 11, 4. But in hexadecimal CC, the numbers 12 and 11 correspond to the number C and B. Therefore, we have:

0.214 10 \u003d 0.36C8B4 16.

Example 10 . We translate the number 0.512 from a decimal number system in the octal SS.

		0.512
	x.	8
4		0.096
	x.	8
0		0.768
	x.	8
6		0.144
	x.	8
1		0.152
	x.	8
1		0.216
	x.	8
1		0.728

Received:

0.512 10 =0.406111 8 .

Example 11 . We translate the number 159.125 from a decimal number system to binary SS. To do this, we translate separately an integer part of the number (Example 4) and the fractional part of the number (Example 8). Next, we get the merging of these results:

159.125 10 =10011111.001 2 .

Example 12 . We transfer the number 19673.214 from a decimal number system to hexadecimal. To do this, we translate separately an integer part of the number (Example 6) and the fractional part of the number (example 9). Next, we get the combining results.

The construction market is popular for 2 sizes of structures:

1 \\ 2 and 3 \\ 4 - constitute a separate category. Due to the special thread parameters (1.814), by 1 unit. Measures account for 14 threads;
within 1 - 6 inches, a step decreases to 2.309, forming 11 threads that do not affect the reduction or improvement of the quality of the connection.

One inch is a length of 25.4 mm, it is used to determine the internal parameters, but when laying reinforced pipes, the diameter is 33.249 mm (including the inner section and 2 walls). In the assortment steel structures There is an exception - products in ½ inches, where the outer cross section is 21.25 mm. This parameter is used when calculating the dimensions of pipes with a cylindrical thread type. When calculations for pipes with a cross-section of 5 inches, the inner size will be 12.7 cm, and the external - 166,245 (reduced to 1 decimal sign).

The difference between measurement systems

According to external parameters, inches do not differ from the metric, the difference lies in the type of notch. Two types of threads in the inch system - English and American. The first option corresponds to the corner of the notch 55 gr., And the metric (American) system with an angle of 60 gr. Generally accepted.

With different degrees, it is difficult to distinguish an angle of 55 - in inches and 60 - in metric structures, and the yarns of the threads are visible immediately, the occurrence of the error is impossible. For measurement step, the thread is a threader, but instead it is well used a common line or another device.

Replacing steel pipes polymer

Steel products are used in the gas and water supply network, the diameter of which is indicated in inches (1 ", 2") or shares (1/2 ", 3/4). When the cross section is measured 1, "resulting in 33.5 mm, which corresponds to 1" (25.4 mm). With the arrangement of pipeline reinforcing elements, where the parameters are indicated in inches, there are no difficulties. But when installing instead of steel structures, products from PP, copper or stainless steel, it is required to take into account the difference in the name and parameters.

To create a given stream level, the inner diameter of pipes is taken into account. For inch ordinary pipes, it is 27.1 mm, for reinforced 25.5 mm, the most approximate to 1 ". Pipelines are denoted in conventional units of the du (Dn). It determines the parameters of the lumen of the pipes and is indicated in the digital values. Sections are selected, taking into account the increase in the capacity by 40-60% with increasing index. If external is known cross section And the design of the structures using the size table is determined by the inner cross section.

In the process of compound steel pipes With polymer structures, replacing one to others, ordinary adapters are used. The inconsistency of the size is obtained as a result of the use of copper, aluminum or stainless steel products manufactured by metric standards. Real metric dimensions of pipes are taken into account - internal and external.

Steel pipes of the Russian Federation in comparison with Eurostandard

For comparison of the sorting of pipes according to GOST RF and Eurostandards, the following table is used:

How to determine the choice of diameter?

From diameter water pipes Their bandwidths depend on the volume of water skipped for 1 unit. time. It depends on the speed of water flow. With its increase, the risk of pressure drop in the highway increases. Bandwidth characteristics are calculated by formulas, but planning intra-ordinary wiring, take the pipes of certain parameters.

For a plumbing system:

1.5 cm (1/2 inches)
1 cm (3/8 inches).

For the riser, structures with an internal cross section are used:

2.5 cm (1 inch);
2 cm (3/4 inches).

Taking into account the fact that the inner cross section of the semi-le polymer pipes Various in the range from 11 to 13 mm, and one-name - from 21 to 23, to determine the exact parameters when replacing an experienced plumber will be able to determine. With a complex type of wiring, numerous joints, turning and network gaskets on a large distance, reduce pressure, should provide the possibility of performing pipe wiring with a large cross section. With an increase in diameter, the level of pressure is increased.

Below is a table for determining the passability of steel pipes:

Pipe diameter of steel

The cross section of the pipes corresponds to a number of indicators:

The conditional diameter (Du, DY) is the nominal parameters (in mm) of the inner cross section of pipes or their rounded indicators, in inches.
Nominal parameter (DN DN,).
External size.
The metric calculation system allows you to classify the structures to small - from 5 ... 102 mm, medium - from 102 ... 426, large - 426 mm and more.
Wall thicknesses.
Internal diameter.

The inner cross section in pipes with different threads corresponds to the parameters:

1/2 inches pipeline - 1.27 cm;
3/4 inches - 1.9 cm;
7/8 inches - 2.22 cm;
1 inch - 2.54 cm;
1.5 inches - 3.81 cm;
2 inches - 5.08 cm.

To determine the thread diameter, the following indicators are used:

1/2 inches pipeline - 2.04 - 2.07 cm;
3/4 inches - 2, 59 - 2.62 cm;
7/8 inches - 2.99 - 3 cm;
1 inch - 3.27 - 3, 3 cm;
1.5 inches - 4.58 - 4.62 cm;
2 inches - 5.79 - 5.83 cm.

Table matching the diameter of steel pipes by polymer structures:

Steel pipe prices:

Diameter of pipes PP.

PP pipes are produced with a diameter of 0.5 to 40 cm and more. The diameter is internal and outdoor. The first indicator allows you to find out the amount of media passable for 1 unit. time. The external cross section is used to carry out construction counts, namely the choice of a niche or pit for laying a highway. External parameters allow you to correctly select fittings with the corresponding internal indicators.

Small - 0.5; one; 1.5; 2; 2.5; 3.2; four; five; 6.3 and 7.5 cm serves for heating systems, drain and water supply in private buildings. The inner cross section is 3.2 cm most popular in high-rise buildings.
Current - 8; nine; 10; eleven; 12.5; sixteen; twenty; 25 and 31.5 cm serves to arrange water pipeline and sewage systems, allowing you to change cast iron products with similar external parameters. Internal size In 8, 9 and 10 cm perfect for chemical environments.
Big - 40 cm and more used to improve cold water supply and ventilation systems.

Pipes are marked in inches and mm. When choosing structures for plumbing and heating system, the wall thickness is taken into account, which affects the conditional lifeline of highways with the same external parameters. With an increase in its parameter, pressure is allowed in watering system. Small dimensions make it possible to reduce the level of the cost of buying material and water consumption.

Cost of PP pipes:

Video

Conical and cylindrical thread

Stem itself with applied to him conical carvings It is a cone. Moreover, according to international rules, the taper must be 1 to 16, that is, for every 16 units of measurement (millimeters or inches) with an increase in distance from the starting point, the diameter increases by 1 corresponding unit of measurement. It turns out that the axis around which the carving is applied and the conditional direct, conducted from the beginning of the thread before it is completed along the shortest path - are not parallel, but are one to each other at a certain angle. If you explain even easier, if we have the length of the threaded compound, 16 centimeters were 16 centimeters, and the diameter of the rod at its starting point would be 4 centimeters, then at a point where the thread ends, the diameter would already be 5 centimeters.

Stem S. cylindrical thread It is a cylinder, respectively, there is no taper.

Thread (metric and inches)

Pipe carving cylindrical according to GOST 6357-52
Designation	Number N. on 1 "	Pitch thread S, mm.	Outside diameter Threads, mm.	Middle diameter Threads, mm.	Inner diameter Threads, mm.
G1 / 8 "	28	0,907	9,729	9,148	8,567
G1 / 4 "	19	1,337	13,158	12,302	11,446
G3 / 8 "	19	1,337	16,663	15,807	14,951
G1 / 2 "	14	1,814	20,956	19,754	18,632
G3 / 4 "	14	1,814	26,442	25,281	24,119
G7 / 8 "	14	1,814	30,202	29,040	27,878
G1 "	11	2,309	33,250	31,771	30,292

Nominal diameter of thread

Marking is usually present nominal diameterFor which in most cases the outer diameter of the thread is accepted. If the carving is metric, then for measurement you can use a regular caliper with scales in millimeters. Also diameter, like a thread step, you can see special tables.

Metric and inch thread on examples

Metric carving - It has the designation of the main parameters in millimeters. For example, consider an angular fitting with external cylindrical carvings. EPL 6-GM5. In this case, EPL suggests that the fitting of the corner, 6-ka is 6 mm - the external diameter of the tube connected to fitting. Liter "G" in its marking reports that the carving is cylindrical. "M" indicates that the carving is metric, and the figure "5" indicates the nominal diameter of a thread equal to 5 millimeters. Fittings (from those that are available on sale) with a literary "G" are also equipped with a rubber sealing ring, and therefore do not require fum-tapes. The thread step in this case is 0.8 millimeters.

Conical and cylindrical thread profiles coincide, which allows you to perenify the fittings with conic threads and cylindrical.