Pipe diameters. Converting numbers to different number systems with solution Difference between measurement systems

BASIC PARAMETERS OF INCH THREADS
(BSW (Ww), BSF, UNC, UNF standards)

The peaks and valleys of an inch thread, similar to a metric one, are flat. The pitch of an inch thread is determined by the number of threads (turns) per inch 1 ", but its top angle is 55 ° (Whitworth's thread is British BSW (Ww) and BSF), the nose angle is 60 ° (American UNC and UNF ).

Outer thread diameter is measured in inches 1 "\u003d 25.4 mm - dash (") symbol for inch. Inch thread is characterized by the number of threads per inch. According to American standards, inch threads are made with coarse (UNC) and fine (UNF) pitches.
NPSM - American standard for inch cylindrical pipe thread.
NPT - American standard for inch conical thread.

Standards:

ASME / ANSI B1.1 - 2003 Unified Inch Screw Threads, UN & UNR Thread Form
ASME / ANSI B1.10M - 2004 Unified Miniature Screw Threads
ASME / ANSI B1.15 - 1995 Unified Inch Screw Threads, UNJ Thread Form

AMERICAN INCH THREAD

The main parameters of an inch thread:

d (D) - the outer diameter of the thread, respectively, of the bolt and nut;
d p \u200b\u200b(D p) - the average diameter of the thread, respectively, of the bolt and nut;
d i (D i) - internal thread diameter of the bolt and nut, respectively;
n- the number of threads per inch.

American Coarse Thread - UNS

Thread sizes, inches (mm)	D	*D p*	*D i*	Thread sizes, inches (mm)	D	*D p*	*D i*
Thread sizes, inches (mm)				Thread sizes, inches (mm)
№1 (1,8542)
№2 (2,1844)				1 (25,4)
№3 (2,5146)				1 1/8 (28,58)
№4 (2,8448)				1 1/4 (31,75)
№5 (3,1750)				1 3/8 (34,925)
№6 (3,5052)				1 1/2 (38,10)
№8 (4,1656)				1 3/4 (44,45)
№10 (4,8260)
№12 (5,4864)				2 (50,8)
				2 1/4 (57,15)
1/4 (6,3500)				2 1/2 (63,5)
5/16 (7,9375)				2 3/4 (69,85)
3/8 (9,5250)
7/16 (11,1125)				3 (76,2)
1/2 (12,700)				3 1/4 (82,55)
9/16 (14,2875)				3 1/2 (88,9)
5/8 (15,8750)				3 3/4 (95,25)
3/4 (19,0500)				4 (101,6)
7/8 (22,2250)

American Fine Pitch Thread - UNF

Thread sizes, inches (mm)	D	*D p*	*D i*	Thread sizes, inches (mm)	D	*D p*	*D i*
Thread sizes, inches (mm)				Thread sizes, inches (mm)
№0 (1,524)				3/8 (9,525)
№1 (1,8542)				7/16 (11,1125)
№2 (2,1844)				1/2 (12,700)
№3 (2,5146)				9/16 (14,2875)
№4 (2,8448)				5/8 (15,875)
№5 (3,1750)				3/4 (19,050)
№6 (3,5052)				7/8 (22,225)
№8 (4,1656)
№10 (4,8260)				1 (25,4)
№12 (5,4864)				1 1/8 (28,58)
				1 1/4 (31,75)
1/4 (6,350)				1 3/8 (34,925)
5/16 (7,9375)				1 1/2 (38,10)

American thread with extra fine pitch - UNEF

Thread sizes, inches (mm)	D	*D p*	*D i*	Thread sizes, inches (mm)	D	*D p*	*D i*
Thread sizes, inches (mm)				Thread sizes, inches (mm)
№12 (5,4864)
				1 (25,4)
1/4 (6,350)				1 1/16 (26,987)
5/16 (7,9375)				1 1/8 (28,58)
3/8 (9,525)				1 3/16 (30,162)
7/16 (11,1125)				1 1/4 (31,75)
1/2 (12,700)				1 5/16 (33,337)
9/16 (14,2875)				1 3/8 (34,925)
5/8 (15,875)				1 7/16 (36,512)
11/16 (17,462)				1 1/2 (38,10)
3/4 (19,050)				1 9/16 (39,687)
13/16 (20,637)				1 5/8 (41,27)
7/8 (22,225)				1 11/16 (42,86)
15/16 (23,812)

Thread sizes are the outside diameter of a thread, expressed in fractions of an inch. One of the main characteristics of an inch screw thread is the number of turns per inch of thread length (n). The number of turns and the thread pitch P are related by the ratio:

American standards provide for two forms of thread:

Flat-bottomed thread, designated UN;
- thread with a radial root, which is designated by the letters UNR.

The standard defines three classes of thread accuracy. These classes are designated as 1A, 2A, 3A, 1B, 2B, 3B. Accuracy classes 1A, 2A, 3A refer to external threads; accuracy classes 1B, 2B, 3B refer to internal threads. Accuracy class 1A, 1B is the coarsest and is used in cases where quick and easy assembly is required, even with partially dirty and dented threads. Accuracy class 2A, 2B is the most common and is used for general purpose threads. Accuracy class 3A, 3B makes the most stringent requirements for threads and is used in cases where it is required to ensure minimum clearance in threaded connection.

Thread designation... The nominal size is recorded first, followed by the number of threads per inch of thread, the thread group symbols, and the precision class symbol. The letters LH at the end of the entry indicate a left-hand thread. The nominal size is the outside diameter, defined as a fractional size or thread number, or their decimal equivalent.
For example: 1/4 - 20UNS - 2A or 0.250 - 20UNC - 2A

BRITISH STANDARD INCH THREADS
(BSW (Ww) and BSF)

Identification carvings	BSP the size in	thread pitch		largest diameter		smallest diameter		A / F mm	length mm	pipes				thread hole diameter (for drill) mm
Identification carvings	BSP the size in	in (TPI)	mm	mm	in	mm	in	A / F mm	length mm	DN mm	OD mm	OD in	thickness mm	BSP.PL (Rp)	BSP.F (G)
-1	1 / 16	28	0,907	7,723	0,304	6,561	0,2583		4 ± 0.9					6,60	6,80
-2	1 / 8	28	0,907	9,728	0,383	8,565	0,3372	15	4 ± 0.9	6	10,2	0,40	2	8,60	8,80
-4	1 / 4	19	1,337	13,157	0,518	11,445	0,4506	19	6 ± 1.3	8	13,5	0,53	2,3	11,50	11,80
-6	3 / 8	19	1,337	16,662	0,656	14,950	0,5886	22/23	6.4 ± 1.3	10	17,2	0,68	2,3	15,00	15,25
-8	1 / 2	14	1,814	20,955	0,825	18,633	0,7336	27	8.2 ± 1.8	15	21,3	0,84	2,6	18,75	19,00
-10	5 / 8	14	1,814	22,911	0,902	20,589	0,8106			16			2,6	-	21,00
-12	3 / 4	14	1,814	26,441	1,041	24,120	0,9496	32	9.5 ± 1.8	20	26,9	1,06	2,6	24,25	24,50
-16	1	11	2,309	33,249	1,309	30,292	1,1926	43	10.4 ± 2.3	25	33,7	1,33	3,2	30,40	30,75
-20	1 1 / 4	11	2,309	41,910	1,650	38,953	1,5336	53	12.7 ± 2.3	32	42,4	1,67	3,2	39,00	39,50
-24	1 1 / 2	11	2,309	47,803	1,882	44,846	1,7656	57	12.7 ± 2.3	40	48,3	1,90	3,2	45,00	45,00
-32	2	11	2,309	59,614	2,347	56,657	2,2306	70	15.9 ± 2.3	50	60,3	2,37	3,6	56,75	57,00
-40	2 1 / 2	11	2,309	75,184	2,960	72,227	2,8436		17.5 ± 3.5	65	76,1	3,00	3,6
-48	3	11	2,309	87,884	3,460	84,927	3,3436		20.6 ± 3.5	80	88,9	3,50	4
-64	4	11	2,309	113,030	4,450	110,073	4,3336		25.5 ± 3.5	100	114,3	4,50	4,5
-80	5	11	2,309	138,430	5,450	135,472	5,3335		28.6 ± 3.5	125	139,7	5,50	5
-96	6	11	2,309	163,830	6,450	160,872	6,3335		28.6 ± 3.5	150	165,1	6,50	5

Converting integers and fractions from one number system to any other - theory, examples and solutions

There are positional and non-positional number systems. Arabic numeral system that we use in everyday life, is positional, but Roman is not. In positional number systems, the position of the number uniquely determines the value of the number. Let's look at the example of the number 6372 in decimal notation. Let's enumerate this number from right to left starting from zero:

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). The values \u200b\u200bof the position of the given number are taken as degrees.

Consider a real decimal number 1287.923. Let's number it starting from zero 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 + D 0 s 0 + D -1 s -1 + D -2 s -2 + ... + D -k s -k

where Ц n is an integer in position n, Д -k - fractional number in position (-k), s - number system.

A few words about number systems. A number in the decimal number system consists of many digits (0,1,2,3,4,5,6,7,8,9), in the octal number system - of many numbers (0,1, 2,3,4,5,6,7), in the binary number system - from the set of digits (0,1), in the hexadecimal number system - from the set 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 numbers 10,11,12,13,14,15. numbers in different systems reckoning.

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

Converting numbers from one number system to another

To convert numbers from one number system to another, the easiest way is to first convert the number to the decimal number system, and then, from decimal system numbers translate into the required number system.

Converting numbers from any number system to the decimal number system

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

Example 1. Convert the number 1011101.001 from binary number system (SS) to 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. Convert 1011101.001 from octal number system (SS) to decimal SS. Decision:

Example 3 ... Convert number AB572.CDF from hexadecimal base to decimal SS. Decision:

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

Converting numbers from a decimal number system to another number system

To convert numbers from the decimal number system to another number system, you need to translate separately the integer part of the number and the fractional part of the number.

The whole part of the number is transferred from the decimal SS to another number system - by sequentially dividing the whole part of the number by the base of the number system (for a binary SS - by 2, for an 8-ary SS - by 8, for a 16-ary - by 16, etc.) ) until a whole residue is obtained, less than the base CC.

Example 4 ... Let's convert the number 159 from decimal SS to 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 seen from Fig. 1, the number 159 when divided by 2 gives the quotient 79 and the remainder 1. Further, the number 79, when divided by 2, gives the quotient 39 and the remainder 1, etc. As a result, having built a number from the remainder of the division (from right to left), we get the number in the binary SS: 10011111 ... Therefore, we can write:

159 10 =10011111 2 .

Example 5 ... Let's convert the number 615 from decimal SS to octal SS.

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

When converting a number from decimal SS to octal SS, you need to sequentially divide the number by 8 until you get a whole remainder less than 8. As a result, building the number from the remainders of the division (from right to left), we get the number in octal SS: 1147 (see Fig. 2). Therefore, we can write:

615 10 =1147 8 .

Example 6 ... Converting the number 19673 from decimal to hexadecimal SS.

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

As can be seen from Figure 3, by sequentially dividing 19673 by 16, we got the remainders 4, 12, 13, 9. In the hexadecimal number system, 12 corresponds to C, and 13 corresponds to D. Therefore, our hexadecimal number is 4CD9.

To convert correct decimal fractions (a real number with a zero integer part) to a base s, you need given number multiply sequentially by s until a pure zero is obtained in the fractional part, or we get the required number of digits. If the multiplication results in a nonzero number with an integer part, then this integer part is not taken into account (they are sequentially added to the result).

Let's consider the above with examples.

Example 7 ... Converting the number 0.214 from decimal 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 sequentially multiplied by 2. If the multiplication results in a nonzero number with an integer part, then the integer part is written separately (to the left of the number), and the number is written with a zero integer part. If, when multiplying, you get a number with a zero integer part, then zero is written to the left of it. The multiplication process continues until a pure zero is obtained in the fractional part, or the required number of digits is obtained. Writing down bold numbers (Fig. 4) from top to bottom, we get the required number in the binary system: 0. 0011011 .

Therefore, we can write:

0.214 10 =0.0011011 2 .

Example 8 ... Let's convert the number 0.125 from the decimal number system to the binary SS.

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

To convert the number 0.125 from the decimal SS to binary, this number is sequentially multiplied by 2. In the third stage, it turned out 0. Therefore, the following result was obtained:

0.125 10 =0.001 2 .

Example 9 ... Let's convert 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 get the numbers 3, 6, 12, 8, 11, 4. But in the hexadecimal SS, the numbers 12 and 11 correspond to the numbers C and B. Therefore, we have:

0.214 10 \u003d 0.36C8B4 16.

Example 10 ... Converting Decimal to Octal number 0.512.

		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

Got:

0.512 10 =0.406111 8 .

Example 11 ... Converting the number 159.125 from Decimal to Binary SS. To do this, we translate separately the integer part of the number (Example 4) and the fractional part of the number (Example 8). Further, combining these results, we get:

159.125 10 =10011111.001 2 .

Example 12 ... Converting the number 19673.214 from decimal to hexadecimal SS. To do this, we translate separately the integer part of the number (Example 6) and the fractional part of the number (Example 9). Further, combining these results, we get.

The calculator allows you to convert whole and fractional numbers from one number system to another. The base of the number system cannot be less than 2 and more than 36 (10 digits and 26 Latin letters after all). Numbers must not exceed 30 characters. To enter fractional numbers use the symbol. or, . To convert a number from one system to another, enter the original number in the first field, the base of the original number system in the second and the base of the number system to which you want to translate the number in the third field, and then click the "Get Record" button.

Original number recorded in 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 -th number system.

I want to get a record of the number in 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 -th number system.

Get Record

Completed translations: 1710505

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Number systems

Number systems are divided into two types: positional and not positional... We use the Arabic system, it is positional, and there is also the Roman - it is just not positional. In positional systems, the position of a digit in a number uniquely determines the value of that number. This is easy to understand by considering the example of a number.

Example 1... Let's take the number 5921 in decimal notation. Let's number the number from right to left starting from zero:

The number 5921 can be written in the following form: 5921 \u003d 5000 + 900 + 20 + 1 \u003d 5 · 10 3 + 9 · 10 2 + 2 · 10 1 + 1 · 10 0. The number 10 is a characteristic that determines the number system. The values \u200b\u200bof the position of the given number are taken as degrees.

Example 2... Consider the real decimal number 1234.567. Let's number it starting from the zero position of the number from the decimal point to the left and right:

The number 1234.567 can be written as follows: 1234.567 \u003d 1000 + 200 + 30 + 4 + 0.5 + 0.06 + 0.007 \u003d 1 · 10 3 + 2 · 10 2 + 3 · 10 1 + 4 · 10 0 + 5 · 10 -1 + 6 · 10 -2 + 7 · 10 -3.

Converting numbers from one number system to another

Most in a simple way transferring a number from one number system to another is the translation of the number first into the decimal number system, and then, the result obtained in the required number system.

Converting numbers from any number system to the decimal number system

To convert a number from any number system to decimal, it is enough to number its digits, starting from zero (the place to the left of the decimal point) similar to examples 1 or 2. Let's find the sum of the products of the digits of the number by the base of the number system in the power of the position of this digit:

1. Convert the number 1001101.1101 2 to decimal notation.
Decision: 10011.1101 2 \u003d 1 2 4 + 0 2 3 + 0 2 2 + 1 2 1 + 1 2 0 + 1 2 -1 + 1 2 -2 + 0 2 -3 + 1 2 - 4 \u003d 16 + 2 + 1 + 0.5 + 0.25 + 0.0625 \u003d 19.8125 10
Answer: 10011.1101 2 = 19.8125 10

2. Convert E8F.2D 16 to decimal notation.
Decision: E8F.2D 16 \u003d 14 16 2 + 8 16 1 + 15 16 0 + 2 16 -1 + 13 16 -2 \u003d 3584 + 128 + 15 + 0.125 + 0.05078125 \u003d 3727.17578125 10
Answer: E8F.2D 16 \u003d 3727.17578125 10

Converting numbers from a decimal number system to another number system

To convert numbers from the decimal number system to another number system, the integer and fractional parts of the number must be translated separately.

Converting the integer part of a number from the decimal number system to another number system

The integer part is converted from the decimal number system to another number system by sequentially dividing the whole part of the number by the base of the number system until the whole remainder is obtained, which is less than the base of the number system. The result of the transfer will be an entry from the balance, starting with the last one.

3. Convert number 273 10 to octal number system.
Decision: 273/8 \u003d 34 and remainder 1, 34/8 \u003d 4 and remainder 2, 4 is less than 8, so the calculations are complete. The remainder record will look like this: 421
Check: 4 8 2 + 2 8 1 + 1 8 0 \u003d 256 + 16 + 1 \u003d 273 \u003d 273, the result is the same. This means that the translation was done correctly.
Answer: 273 10 = 421 8

Consider the conversion of correct decimal fractions to various systems reckoning.

Converting the fractional part of a number from the decimal number system to another number system

Recall that the correct decimal called real number with zero integer part... To convert such a number to the base N number system, you need to sequentially multiply the number by N until the fractional part is zero or the required number of digits is obtained. If, during multiplication, a number with an integer part that is different from zero is obtained, then the integer part is not taken into account further, since it is sequentially entered into the result.

4. Convert Binary number 0.125 10.
Decision: 0.125 2 \u003d 0.25 (0 is the integer part, which will become the first digit of the result), 0.25 2 \u003d 0.5 (0 is the second digit of the result), 0.5 2 \u003d 1.0 (1 is the third digit of the result, and since the fractional part is equal to zero , then the translation is complete).
Answer: 0.125 10 = 0.001 2

2 sizes of structures are popular in the construction market:

1 \\ 2 and 3 \\ 4 - make up a separate category. due to special thread parameters (1.814), per 1 unit. measures account for 14 threads;
within 1 - 6 inches, the pitch is reduced to 2.309, forming 11 threads, which does not affect the decrease or increase in the quality of the connection.

One inch is 25.4 mm long, it is used to determine internal parameters, but when reinforced pipes are installed, the diameter is 33.249 mm (including internal section and 2 walls). In assortment steel structures there is an exception - ½ "products, where the outer section is 21.25 mm. This parameter is used when calculating the dimensions of pipes with a cylindrical thread type. When calculating for pipes with a cross section of 5 inches, the inner dimension will be 12.7 cm, and the outer dimension will be 166.245 (abbreviated to 1 decimal place is allowed).

Difference between measurement systems

In terms of external parameters, inch designs do not differ from metric ones, the difference lies in the type of notches. There are 2 types of threads according to the inch system - English and American. The first option corresponds to a notch angle of 55 degrees, and the metric (American) system with an angle of 60 degrees. generally accepted.

At different degrees, it is difficult to distinguish the angle at 55 - for inch and 60 - for metric designs, and the filaments are immediately visible, an error is impossible. A thread gauge is used to measure the thread pitch, but a regular ruler or other device is well used instead.

Replacement of steel pipes with polymer

In the gas and water supply network, steel products are used, the diameter of which is indicated in inches (1 ", 2") or fractions (1/2 ", 3/4"). When measuring a pipe cross-section of 1 ", the result is 33.5 mm, which corresponds to 1" (25.4 mm). When arranging pipeline reinforcing elements, where the parameters are indicated in inches, there are no difficulties. But when installing PP, copper or stainless steel products instead of steel structures, it is necessary to take into account the difference in the name and parameters.

To create a given flow rate, the internal diameter of the pipes is taken into account. For inch ordinary pipes, it is 27.1 mm, for reinforced 25.5 mm, the closest to 1 ". Pipelines are designated in conventional units of flow area DN (DN). It determines the parameters of the pipe clearance and is indicated in numerical values. sections are selected taking into account an increase in throughput characteristics by 40-60% with an increase in the index.If the external cross section is known and the purpose of the structures, using the size table, the internal cross section is determined.

In the process of connecting steel pipes with polymer structures, replacing one with another, conventional adapters are used. Dimensional mismatch results from the use of copper, aluminum or stainless steel products manufactured to metric standards. The real metric dimensions of the pipes are taken into account - internal and external.

Steel pipes of the Russian Federation in comparison with the European standard

To compare the range of pipes according to GOST RF and European standards, the following table is used:

How to decide on the choice of diameter?

From diameter water pipes their throughput characteristics depend - the volume of water passed per unit. time. It depends on the rate of flow of water. With its increase, the risk of pressure drop in the line increases. Throughput characteristics are calculated according to the formulas, but when planning intra-apartment wiring, pipes of certain parameters are taken.

For the plumbing system:

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

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

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

Considering that the internal cross-section of the half-inch polymer pipes varies in the range from 11 to 13 mm, and one-inch - from 21 to 23, an experienced plumber will be able to determine the exact parameters when replacing. With a complex type of wiring, numerous joints, turns and laying the network at a long distance, a decrease in pressure, it is necessary to provide for the possibility of routing pipes with a large cross-section. As the diameter increases, the pressure level increases.

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

Steel pipe diameter

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

Nominal diameter (DN, Dy) - nominal parameters (in mm) of the internal cross-section of pipes or their rounded indicators, in inches.
Nominal parameter (Dn Dn,).
External size.
The metric calculation system allows you to classify structures into small - from 5 ... 102 mm, medium - from 102 ... 426, large - 426 mm and more.
Wall thickness.
Inner diameter.

The internal cross-section of pipes with different threads corresponds to the parameters:

1/2 inch pipeline - 1.27 cm;
3/4 "- 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.

The following indicators are used to determine the thread diameter:

1/2 inch pipeline - 2.04 - 2.07 cm;
3/4 '' - 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.

Correspondence table of the diameter of steel pipes to polymer structures:

Steel pipe prices:

PP pipe diameter

PP pipes are produced with a diameter of 0.5 to 40 cm and more. Diameter is internal and external. The first indicator allows you to find out the volume of media traversed in 1 unit. time. The outer cross-section is used for construction calculations, namely the choice of a niche or pit for laying the highway. External parameters allow you to choose the right fittings with the appropriate internal parameters.

Small - 0.5; one; 1.5; 2; 2.5; 3.2; 4; five; 6.3 and 7.5 cm is used for heating systems, drainage and water supply in private buildings. An internal cross-section of 3.2 cm is most popular in multi-storey buildings.
Average - 8; nine; ten; eleven; 12.5; 16; 20; 25 and 31.5 cm is used for arranging water supply and sewerage systems, allowing you to change cast iron products with similar external parameters. Internal sizes of 8, 9 and 10 cm are ideal for chemical environments.
Large - 40 cm or more is used for arranging cold water supply and ventilation systems.

Pipes are marked in inches and mm. When choosing designs for plumbing and heating system, the wall thickness is taken into account, which affects the conditional permeability of highways with the same external parameters. With an increase in its parameter, an increase in pressure in the water supply system is allowed. Small dimensions reduce the cost of purchasing material and water consumption.

PP pipes cost:

Video

In Western technical literature, you will find all measurements in inches. This state of affairs has historical roots. Great Britain has always been ahead in terms of technical development, therefore, in all the colonies that it then owned (and there were many of them), this particular system of measurements was applied. Basically, technicians are free to translate inches to sentiment and vice versa. So to this day in these countries all measurements are made in inches as standard. Next, we will talk about the main features and characteristics of an inch thread and how it differs from a metric one.

Inch thread. Parameters

If we talk about ordinary measurement, then even in the mind it will not be difficult to transfer one value to another and vice versa. But as far as the thread is concerned, you need to know the simple, but important nuances... The fact is that the metric and inch metrics for measuring lengths have large coincidences. The difference is the number of turns in the thread pitch. In addition, this thread has a different angle of inclination at its top, which is equal to 55 ° when referring to Whitworth style. This is considered the norm in England, or, as they say, the "British corner". If we take as a basis the UNC and UNF standards, which are considered the standard in America, then the angle here is 60 °.

Metric and inch threads. The most fundamental differences

Inch thread types:

Outdoor;
Conical;
Cylindrical;
Internal.

1 inch \u003d 25.4 mm. This is the main difference. In documents it has a certain designation - 1´ (with a stroke).

If we talk about American standards, then they have a division into threads with a large pitch, which they designate as UNC and with a small one - UNF. Also, for canonical inch threads, the designation is NPT, and for pipe threads it is NPSM.

What is the thread and where is it used

The types of threads used in production, construction and design, depending on the part, are divided into internal, external and conical.

The outer is used for bolts, screws, pins and studs.
The inner one is used in the manufacture of plugs or nuts. It is cut in holes when you need to organize a connection in a certain place.
To create a tight connection, as well as stopping without additional parts, a tapered inch thread is made.

Their designation follows the standard. d (D) - outside diameter of the bolt or inside diameter of the nut (d-diameter of the bolt before threading). The inside thread diameter is designated d1 (D1). There is also a designation for the average diameter d2 (D2). This dimension depends on the nominal pitch, denoted by the letter P.

To designate the profile angle of the thread, use the letter α. An α \u003d 55 ° will mean that the angle at the top of an equilateral triangle of the thread tooth is 55 °, and corresponds to BSW inch thread according to British Standard. The UTS inch thread, which is widely used in Canada and the USA, has α \u003d 60 °.

Where are inch threads used?

α \u003d 55 ° -inch thread used in industry for fixing mechanical assemblies and parts using threaded connections. It is especially common in the process of repairing imported equipment and machine tools, as well as used cars. Hardware with an inch thread are also produced in our country. During operation, sometimes there is a need to convert metric threads to inch and vice versa. This can be done easily, quickly and conveniently with the help of a special reference book.

Threads are divided into metric and inch units. Metric and inch threads are used in threaded connections and screw drives. Threaded connections are called detachable connections made using threaded fasteners - bolts, screws, nuts, studs or threads directly applied to the connected parts.

Metric thread (fig. 1)

In profile, it looks like an equilateral triangle with an apex angle of 60 °. The tops of the projections of the mating screw and nut are cut off. It is characterized by a metric thread with a screw diameter in millimeters and a thread pitch in millimeters. Metric threads are made with coarse and fine pitch. The main thread is taken with a large pitch. Fine thread is used for adjustment, for screwing thin-walled, as well as dynamically loaded parts. Coarse metric threads are designated by the letter M and a number expressing the nominal diameter in millimeters, for example M20. For fine metric threads, the pitch is additionally indicated, for example, M20x1.5.

Fig. 1 Metric thread

Inch thread (fig. 2)

An inch thread (Fig. 2) has the same shape in profile as a metric thread, but its nose angle is 55 ° (Whitworth's thread is British BSW (Ww) and BSF), its nose angle is 60 ° (American standard UNC and UNF). The outside diameter of the thread is measured in inches (1 "\u003d 25.4mm) - the lines (") represent inches. This thread is characterized by the number of threads per inch. Inch American threads are made with coarse (UNC) and fine (UNF) pitches.

Fig. 2 Inch thread

Fastener Size Chart for American Inch UNC Coarse Pitch (60 Degree Profile Angle)

Size in inches	Size in mm	Thread pitch / inch
UNC No. 1	1.854	64
UNC No. 2	2.184	56
UNC No. 3	2.515	48
UNC No. 4	2.845	40
UNC No. 5	3.175	40
UNC No. 6	3.505	32
UNC No. 8	4.166	32
UNC No. 10	4.826	24
UNC No. 12	5.486	24
UNC 1/4	6.35	20
UNC 5/16	7.938	18
UNC 3/8	9.525	16
UNC 7/16	11.11	14
UNC 1/2	12.7	13
UNC 9/16	14.29	12
UNC 5/8	15.88	11
UNC 3/4	19.05	10
UNC 7/8	22.23	9
UNC 1 "	25.4	8
UNC 1 1/8	28.58	7
UNC 1 1/4	31.75	7
UNC 1 1/2	34.93	6
UNC 1 3/8	38.1	6
UNC 1 3/4	44.45	5
UNC 2 "	50.8	4 1/2

Thread

The thread can be internal and external.

An external thread is cut on bolts, pins, screws, pins and on various other cylindrical parts;
Internal threads are cut in fittings, nuts, flanges, plugs, machine parts and metal structures.

Fig. 3 Thread elements

The main thread elements are shown in Fig. 3 These include the following elements:

thread pitch - the distance between the tops or bases of two adjacent turns;
thread depth - distance from the top of the thread to its base;
thread angle - the angle between the lateral sides of the profile in the plane of the axis;
outside diameter - the largest diameter of the bolt thread, measured along the top of the thread perpendicular to the thread axis;
inner diameter - the distance equal to the cylinder diameter at which the thread is screwed on.

More about inch fasteners:

Three thread systems are adopted in mechanical engineering: metric, inch and pipe.

Metric thread (Fig. 145, a) has a triangular profile at the apex of 60 °.

Fig. 145. Thread systems: a - metric, b - inch, c - pipe

There are six types of metric threads: main and fine -1; 2; 3; 4th and 5th. Small threads differ in pitch for a given diameter, expressed in millimeters. Metric threads are designated by the letter M and numbers characterizing the dimension of the outer diameter and pitch. For example, M42X4.5 denotes a metric base with an outer diameter of 42 mm and a pitch of 4.5 mm.

The fine thread, in addition, in the designation has a number indicating the thread number, for example 2M20X1.75 - the second metric fine, outer diameter 20 mm, pitch 1.75 mm.

Inch thread (Fig. 145, b) has an angle of 55 ° at the apex. Inch threads are cut when making spare parts for machines with inch threads and should not be cut on new products. Inch thread is characterized by the number of threads per inch (1 ") of length. Outside diameter inch thread is measured in inches.

Pipe thread(Fig. 145, c) is measured in the same way as an inch, in inches and is characterized by the number of threads per 1 ". The thread profile has an angle of 55 °. For pipe threads, the diameter is conventionally taken as the diameter of the pipe hole, on the outer surface of which it is cut thread.

The tops of the protrusions of the screw and nut with pipe threads are made with flat or rounded cuts.

The flat-cut profile is easier to manufacture and is used for threads of common pipe connections. Pipe thread is designated: 1/4 "PIPE. 1/2" PIPE. and so on (Table 25).

Table 25 Designation of threads in drawings

Thread type	Legend	Designation elements	An example of a bolt and nut thread designation
Metric basic	M	Outside diameter of thread (mm) or outside diameter and pitch (mm)	M64 or M64X6 or 64x6
Metric small	1M		1M 64X4 or 64X4
	2M		2M 64X3 or 64X3
	3m		3M 64X2 or 64X2
	4M		4M 64X1.5 or 64X1.5
	5M		5M 64X1 or 64X1
Trapezoidal	LADDER	Outside diameter and thread pitch (mm)	LADDER. 22x5
	UP		UP 70X10
Inch with a profile angle of 55 °		Nominal thread diameter in inches	1"
Tubular cylindrical	PIPE. PR * PIPE. KR **	Symbol threads in inches	3/4 "PIPE. PR 3/4" PIPE. KR
Tubular conical	PIPE. END		3/4 "PIPE END

* Profile with flat tops (straight). ** Rounded profile.

Threads are right and left; by the number of calls - one-, two-, three-way and multi-way.

In order to determine the number of thread starts, it is enough to look at the end of the screw or nut and count how many ends of the threads there are on it.

As a rule, all fasteners (bolts, screws, screws, etc.) have a single-start thread.

In our metric world, it is sometimes difficult to navigate in other measurement systems. We sometimes wonder how the Americans or the British can use obsolete measures of length, mass, area, etc. And they, in turn, do not understand us - living by the laws unified System Measurements. However, as with any rule, there are certain exceptions that are clear to everyone - the people of America, and Foggy Albion, and Europe, and Russia. This article is devoted to an overview of pipe and metric threads, with a variety of which you often encounter in everyday life.

Metric threads and their applications

Threaded connections are very common in construction, engineering, mechanical engineering, aerospace and everyday life. Even children in kindergarten know what a screw and a nut are, since classes with a designer cannot do without these details. Despite the fact that the first screw was invented by Archimedes, and our ancient ancestors widely used screw drives in presses to squeeze oil from olive pits and sunflower seeds, as well as to raise water for irrigating fields, the idea is to create a present screw connection found its realization only in the 15th century, when one of the Swiss watchmakers for the first time managed to grind the first screw and nut with the help of the simplest devices.

At the same time, mankind did not come to a reasonable idea that the thread should be the same in all countries of the world. So, widespread and familiar to everyone who had even a little experience with technology, the metric thread appeared and was described in the standards only after the introduction of a unified System of Measurements based on the standards of the meter, kilogram and second. So the emergence and widespread use of metric thread dates back to the late 19th century. Until that time, inch carvings dominated the world.

The main difference between a metric thread and an inch thread is that all its parameters are tied to a millimeter, and an equilateral triangle is taken as the basis of the profile of the thread itself, since all of its angular dimensions are the same and equal to 60 degrees. In the standardization of metric threaded connections, it is important that the nut and bolt match not only the angular dimensions of the thread, but also its diameter and pitch. Many, especially those who have cars, have encountered an incomprehensible phenomenon when the screw and nut have the same diameter, but it is impossible to screw the screw into the nut. This indicates that in this place a thread with a smaller pitch is used and in order for the screw to screw in without problems, its thread pitch must also be reduced.

In the standards describing metric threads, it is indicated that they should be indicated by the letter M, and then the thread diameter and its pitch are indicated. The range of diameters of metric threads ranges from one to six hundred millimeters. The spread of the pitch of the thread is from 0.075 to 3.5 mm. Fine pitch threads are used for measuring tool, threads with an average pitch for parts and assemblies loaded and operating in vibration conditions, and threads with a large pitch are used to fasten heavy load-bearing structures.

When creating standards for metric threads, various tolerances were taken into account, which determine the degree of roundness of the outer edge of the thread and deviation from the profile so that the screw and nut can be freely tightened to the stop with the hand.

Although metric threads are not widely used in sealed joints, such a possibility is laid down in the standards. So, the thread with the designation MK is used for self-sealing connections due to the taper of the outer and internal thread... Moreover, for a tight connection, it is not necessary that the screw and nut be with tapered thread. It is enough that this thread is cut on the screw.

Cylindrical metric threads are rare. Her designation is MJ. The main difference is in the screw, which has an increased radius of the root of the thread, which gives a threaded connection based on a cylindrical metric thread, higher heat-resistant and fatigue properties. This thread is used in the aerospace industry. However, a regular metric screw can be screwed into a nut with such a thread.

Despite the universal predominance of right-hand thread in all devices and mechanisms, it is still necessary to implement certain functions use left hand thread. Metric left-hand threads do not differ from right-hand threads, except for the direction of rotation, which is opposite to the right-hand screws. If an ordinary screw is tightened clockwise, then the left screw is unscrewed in the same direction.

Also, sometimes you can meet with a multi-start metric thread. It differs in that not one spiral is cut simultaneously on the bolt and nut, but two or even three. Multiple threads are often used in high-precision equipment, for example, in photographic equipment, in order to uniquely position the position of parts during mutual rotation. Such a thread can be distinguished from the usual one by two or three beginnings of turns at the end.

Despite the very widespread use of metric threads, in many developed countries world traditionally, the so-called inch threads remain in greater use. And pipe threads are universally measured in inches. And, despite the strong differences between these types of threads, plumbers around the world do not need to explain the differences between a half-inch pipe and a three-quarter pipe.

Inch threads and their applications

The difference between inch threads and metric threads is that the angle at the top of the thread is 55 degrees, the thread pitch is calculated as the ratio of the number of threads per inch of thread length. An inch is understood as a distance of 2.54 cm. What originally corresponded to the length of the first phalanx thumb human hands, which are almost the same for all people.

Since the apex angle is different than in metric threads, it is not possible to combine metric and inch threads. In countries with the metric system, only inch pipe threads are used, which are denoted by the letter G. The letter is followed by a fractional or whole denomination, which does not indicate the size of the thread, but the conditional pipe clearance in inches or fractions of an inch. A feature of the pipe thread is precisely the fact that it takes into account the thickness of the pipe walls, which can be thicker or thinner depending on the material of manufacture and the working pressure for which the pipes are designed. Therefore, the inch standard for pipe threads is understood and accepted around the world as an exception to metric rules.

In addition to simple cylindrical pipe threads, there is also a tapered pipe thread. It has the same characteristics as a regular pipe, except for the taper, which allows for more tight connections. It is designated by the letter R for external threads and Rc for internal threads. The left-hand thread is additionally marked with the letters LH, followed by the numerical value in whole and fractional fractions of an inch.

For use in connections other than plumbing, in the United States and Canada, inch threads with an apex angle of 60 degrees are used. There is a fairly wide range of these threads, which differ in the range of the thread pitch and other characteristics. It is worth noting that some threads from the inch range coincide with the metric ones, which in some cases may be on hand. For example, in photography, the diameter of the connecting thread by which the camera is attached to the tripod is the same all over the world, regardless of the country of manufacture, since the characteristics of this thread are the same for both metric and inch threads.

However, do not confuse the English inch industrial carving, which was approved back in 1841, and was developed by Joseph Whitworth himself. This thread practically repeats the pipe thread, since it has an angle at the top of 55 degrees. Screws and nuts with this thread will not mate with inch fasteners from America and Canada.

In this article, I want not only to give dry facts about the dimensions of an inch pipe thread with references to standards and GOSTs, but to bring to the reader an interesting fact about the designation features of the latter.

So, those who have already encountered pipe threads were more than once surprised at the discrepancy between the outer diameter of the thread and its designation. For example, 1/2 inch threads have an outer diameter of 20.95 mm, although logically with metric threads it should be 12.7 mm. The thing is that in the inch thread, the pipe bore is actually indicated, and not the outer diameter of the thread. At the same time, adding the pipe wall to the size of the hole, we get an overestimated outer diameter to which we are used to in the designations of metric threads. Conventionally, the so-called pipe inch is 33.249 mm, that is, 25.4 + 3.92 + 3.92 (where 25.4 is the passage, 3.92 is the pipe wall). The pipe walls are taken based on the working pressure for the thread. Depending on the diameter, the pipes also increase accordingly, since a pipe with a large diameter must have thicker walls than a pipe with a smaller dimater for the same working pressure.

Pipe threads are classified as follows:

Cylindrical pipe thread

This is an inch thread based on BSW (British Standard Whitworth) thread and corresponds to BSP (British standard pipe thread) thread, with four pitches 28,19,14,11 threads per inch. It is cut into pipes up to size 6 ", pipes over 6" are welded.

The angle of the profile at the apex is 55 °, the theoretical height of the profile is Н \u003d 0.960491Р.

Standards:
GOST 6357-81: Basic standards of interchangeability.
Cylindrical pipe thread. ISO R228, EN 10226, DIN 259, BS 2779, JIS B 0202.

Designation: the letter G, the numerical value of the nominal pipe size in inches (inch), the accuracy class of the average diameter (A, B), and the letters LH for left-hand threads. For example, a thread with a nominal diameter of 1 1/4 ", accuracy class A is denoted as G1 1/4-A. Once again, it should be borne in mind that the nominal thread size corresponds to the pipe clearance in inches. The outer diameter of the pipe is in some proportion with this size and more, respectively, for the thickness of the pipe walls.

Cylindrical pipe thread size designation (G), steps and nominal values \u200b\u200bof outer, middle and inner thread diameters, mm

Thread size designation		Step P	Thread diameters
Row 1	Row 2	Step P	d \u003d D	d 2 \u003d D 2	d 1 \u003d D 1
1/16"		0,907	7,723	7,142	6,561
1/8"		0,907	9,728	9,147	8,566
1/4"		1,337	13,157	12,301	11,445
3/8"		1,337	16,662	15,806	14,950
1/2"		1,814	20,955	19,793	18,631
	5/8"		22,911	21,749	20,587
3/4"			26,441	25,279	24,117
	7/8"		30,201	29.0З9	27,877
1"		2,309	33,249	31,770	30,291
	1⅛"		37,897	36,418	34,939
1¼ "			41,910	40,431	38,952
	1⅜"		44,323	42,844	41,365
1½ "			47,803	46,324	44,845
	1¾ "		53,746	52,267	50,788
2"			59,614	58,135	56,656
	2¼ "		65,710	64,231	62,762
2½ "			75,184	73,705	72,226
	2¾ "		81,534	80,055	78,576
3"			87,884	86,405	84,926
	3¼ "		93,980	92,501	91,022
3½ "			100,330	98,851	97,372
	3¾ "		106,680	105,201	103,722
4"			113,030	111,551	110,072
	4½ "		125,730	124,251	122,772
5"			138,430	136,951	135,472
	5½ "		151,130	148,651	148,172
6"			163,830	162,351	160,872