GOST 11284-75: Through holes for fasteners. Dimensions.

In order to connect parts together using rivets, pins, bolts, studs and screws, holes are usually required. For through holes for fasteners , there is a standard that recommends using nominal size values.

GOST 11284 − 75


Through holes for fasteners

d	d1
d	1st row	2nd row	3rd row
1,0	1,1	1,2	1,3
1,2	1,3	1,4	1,5
1,4	1,5	1,6	1,8
1,6	1,7	1,8	2,0
1,8	2,0	2,1	2,2
2,0	2,2	2,4	2,6
2,5	2,7	2,9	3,1
3,0	3,2	3,4	3,6
3,5	3,7	3,9	4,2
4,0	4,3	4,5	4,8
4,5	4,8	5,0	5,3
5,0	5,3	5,5	5,8
6,0	6,4	6,6	7,0
7,0	7,4	7,6	8,0
8,0	8,4	9,0	10,0
10,0	10,5	11,0	12,0
12,0	13,0	14,0 (13,5)	15,0 (14,5)
14,0	15,0	16,0 (15,5)	17,0 (16,5)
16,0	17,0	18,0 (17,5)	19,0 (18,5)
18,0	19,0	20,0	21,0
20,0	21,0	22,0	24,0
22,0	23,0	24,0	26,0
24,0	25,0	26,0	28,0
27,0	28,0	30,0	32,0
30,0	31,0	33,0	35,0
33,0	34,0	36,0	38,0
36,0	37,0	39,0	42,0
39,0	40,0	42,0	45,0
42,0	43,0	45,0	48,0
45,0	46,0	48,0	52,0
48,0	50,0	52,0	56,0
52,0	54,0	56,0	62,0
56	58	62	66
60	62	66	70
64	66	70	74
68	70	74	78
72	74	78	82
76	78	82	86
80	82	86	91
85	87	91	96
90	93	96	101
95	98	101	107
100	104	107	112
105	109	112	117
110	114	117	122
115	119	122	127
120	124	127	132
125	129	132	137
130	134	137	144
140	144	147	155
150	155	158	165
160	165	168	175

Part connections

All connections of various parts that are used in mechanical engineering and instrument making are divided into movable and fixed. In this case, those that ensure the movement of parts relative to each other are considered movable, and those that require rigid fastening between them are considered stationary.

The possibility of repeated assembly and disassembly of components and assemblies of machines and equipment is ensured by detachable connections. These include threaded, splined, keyed, profile, pin and terminal.

Unlike detachable ones, permanent connections cannot be disassembled without damaging the parts. These include welded, adhesive, soldered, riveted joints, as well as joints with guaranteed interference. In technology, connections play an extremely important role, and many malfunctions in the operation of machines and equipment, as well as accidents, often occur because their parts were poorly connected to each other.

THROUGH HOLES FOR FASTENERS DIMENSIONS Through holes for fasteners. Dimensions

Standards → GOST 11284-75: Through holes for fasteners. Dimensions.
STATE STANDARD OF THE USSR UNION
GOST 11284-75 Instead of GOST 11284-65

By Decree of the State Committee of Standards of the Council of Ministers of the USSR dated November 14, 1975 No. 3134, the validity period was established from 01/01/77 to 01/01/87

1. This standard establishes the dimensions of through holes for bolts, screws, studs and rivets with rod diameters from 1.0 to 160 mm, used to connect parts with gaps.

The standard fully complies with the CMEA standardization recommendation PC 107-72 and the ISO recommendation P-273.

2. The dimensions of through holes must correspond to those indicated in the table.

Diameters of fastener rods d

Diameters of through holes d1			Diameters of fastener rods d	Diameters of through holes d1
1st row	2nd row	3rd row	Diameters of fastener rods d	1st row	2nd row	3rd row
1,0	1,2	1,3	—	2,5	2,7	2,9	3,1
1,2	1,4	1,5	—	3,0	3,2	3,4	3,6
1,4	1,6	1,7	—	4,0	4,3	4,5	4,8
1,6	1,7	1,8	2,0	5,0	5,3	5,5	5,8
2.0	2,2	2,4	2,6	6,0	6,4	6,6	7,0

Diameters of fastener rods d	Diameters of through holes d1			Diameters of fastener rods d	Diameters of through holes d1
Diameters of fastener rods d	1st row	2nd row	3rd row	Diameters of fastener rods d	1st row	2nd row	3rd row
7,0	7,4	7,6	8,0	56	58	62	66
8,0	8,4	9,0	10,0	60	62	66	70
10,0	10,5	11,0	12,0	64	66	70	74
12,0	13,0	14,0	15,0	68	70	74	78
14,0	15,0	16,0	17,0	72	74	78	82
16,0	17,0	18,0	19,0	76	78	82	86
18,0	19,0	20,0	21,0	80	82	86	91
20,0	21,0	22,0	24,0	85	87	91	96
22,0	23,0	24,0	26,0	90	93	96	101
24,0	25,0	26,0	28,0	95	98	101	107
27,0	28,0	30,0	32,0	100	104	107	112
30,0	31,0	33,0	35,0	105	109	112	117
33,0	34,0	36,0	38,0	110	114	117	122
36.0	37,0	39,0	42,0	115	119	122	127
39,0	40,0	42,0	45,0	120	124	127	132
42,0	43,0	45,0	48,0	125	129	132	137
45,0	46,0	48,0	52,0	130	134	137	144
48,0	50,0	52,0	56,0	140	144	147	155
52,0	54,0	56,0	62,0	150	155	158	165
52,0	54,0	56,0	62,0	160	165	168	175

Notes:

1. The 3rd row of holes is not allowed to be used for rivet connections

2. Recommendations for selecting rows of through holes are given in the appendix.

3. Limit deviations of hole diameters:

a) for the 1st row - according to H12; b) for the 2nd and 3rd rows - according to H14.

APPENDIX Recommended

RECOMMENDATIONS FOR SELECTING ROWS OF THROUGH HOLES

1. When independently processing the holes of each part of the connection with the distance between the axes of the most distant holes less than 500 mm, for connections for which only assembly requirements are imposed, it is recommended to select rows of through holes according to the table below.

Connection type

Number and location of holes	Hole forming method	Connection type	Recommended number of through holes
Any number of holes and any location	Machining holes for jigs	I and II	1st row
a - holes are located in one row and copied relative to the hole axis or reference plane	Punching holes with high precision dies, injection molding and high precision lost wax casting	I	1st row
		II	2nd row
b - holes (up to four in number) are located in two rows and coordinated relative to their axes	Processing holes according to markings, punching with stamps of normal accuracy, casting of normal accuracy	I	1st row
		II	2nd row
a—holes are located in two or more rows and coordinated relative to the axes of the holes or base planes b—holes are located in a circle	Punching holes with high-precision dies, iodine injection molding and high-precision lost-wax casting	I and II	2nd row
	Processing holes according to markings, punching with stamps of normal accuracy, casting of normal accuracy	I	3rd row

2. For connections that are subject to assembly requirements and additional requirements to ensure a certain degree of relative movement of parts, as well as for connections that are subject to only assembly requirements, but with distances between the axes of the most distant holes in the parts of 500 mm or more, it is allowed to accept more rough (compared to those recommended in the table) rows of through holes.

3. When processing holes in joint parts together (for rivet and permanent bolted connections), the nominal diameter of the through hole is recommended to be taken equal to the largest limiting size of the diameter of the fastener rod. In this case, the holes must be countersunk to a size corresponding to the transition radius between the head and the rod.

Change No. 1 GOST 11284-75. Through holes for fasteners. Dimensions.

By Decree of the USSR State Committee for Standards dated 81 12 03 No. 5218, the introduction date was set from 82 01 01

On the cover and first page, the standard designation should be supplemented with the following designation: (ST SEV 2515-80).

Clause 1. The second paragraph should be stated in a new edition:

“The standard fully complies with ST SEV 2515-80>.

Clause 2 shall be stated in a new edition (except for the table and note):

"2. The dimensions of through holes must correspond to those indicated in the drawing and table.

Table. Replace size designation: d1 with dh; supplement the table with the diameters of the fastener rods d - 1.8; 3.5; 4.5 mm with corresponding dh; column “Diameters of through holes dh” for diameters d of fasteners 1.0; 1.2; 1.4; 12.0; 14.0 and 16.0 mm shall be stated in a new edition:

Diameters of fastener rods d	Diameters of through holes, dh
Diameters of fastener rods d	1st row	2nd row	3rd row
1,0	1,1	1,2	1,3
1,2	1,3	1,4	1,5
1,4	1,5	1,6	1,8
1,8	2,0	2,1	2,2
3,5	3,7	3,9	4,2
4,5	4,8	5,0	5,3
12,0	13,0	14,0 (13,5)	15,0 (14,5)
14,0	15,0	16,0 (15,5)	17,0 (16,5)
16. 0	17,0	18,0 (17,5)	19,0 (18,5)

supplement the table with note - 3:

"3. Dimensions in brackets are not recommended.”

Clause 3 shall be stated in a new wording:

"3. Maximum deviations of hole diameters:

for the 1st row - H12; for the 2nd row - H13; for the 3rd row - H14."

The standard should be supplemented with POINT - 4:

"4. If necessary, eliminate the contact of the hole edge with the radius under the head of the fastener; It is recommended to countersink the hole.”

INTERNATIONAL SYSTEM OF UNITS (SI)

Magnitude	Unit
	Name	Designation
	Name	Russian	international
BASIC UNITS
LENGTH	meter	m	m
WEIGHT	kilogram	kg	kg
TIME	second	With	s
POWER OF ELECTRIC TONE	ampere	A	A
THERMODYNAMIC TEMPERATURE KELVIN	kelvin	TO	TO
SIPA SVETA	candela	KD	CD
ADDITIONAL UNITS
Flat angle	radian	glad	rad
Solid angle	steradian	Wed	sr
DERIVATIVE UNITS
Square	square meter	m2	m2
Volume, capacity	cubic meter	m3	m3
Density	kilogram per cubic meter	kg/m3	kg/m3
Speed	meter per second	m/s	m/s
Angular velocity	radians per second	rad/s	rad/s
Force; gravity (weight)	newton	N	N
Pressure; mechanical stress	pascal	Pa	Pa
Job; energy; quantity of heat	joule	J	J
Power; heat flow	watt	VT	W
Amount of electricity; electric charge	pendant	Cl	WITH
Electrical voltage, electrical potential, electrical potential difference, electromotive force	volt	IN	V
Electrical resistance	ohm	Ohm
Electrical conductivity	Siemens	Cm	S
Electrical capacity	farad	F	F
Magnetic flux	webes*	Wb	Wb
Inductance, mutual inductance.	Henry	G	H
Specific heat	joule per kilogram Kelvin	J/(kg*K)	J/(kg*K)
Thermal conductivity	Watt per meter kelvin	W/(m*K)	W/(m*K)
Light flow	lumen	lm	lm
Brightness	candela per square meter	cd/m2	cd/m2
Illumination	luxury	OK	lx

FACTORS AND PRESCRIPTS FOR FORMING DECIMAL MULTIPLES AND FROM FROM UNITS AND THEIR NAMES

Multiplier by which one is multiplied	Console	Designation		Multiplier by which one is multiplied	Console	Designation
Multiplier by which one is multiplied	Console	Russian	international	Multiplier by which one is multiplied	Console	Russian	international
1012	tera	T	T	10-2	(centi)	With	c
109	giga	G	G	10-3	Milli	m	m
106	mega	M	M	10-6	micro	mk
103	kilo	To	k	10-9	nano	n	n
102	(hecto)	G	h	10-12	pico	P	p
101	(deck)	Yes	da	10-15	femto	f	f
10-1	(deci)	D	d	10-18	atto	A	A
Note: prefixes are indicated in parentheses that can only be used in the names of multiples and submultiples that have already become widespread (for example, hectare, deciliter, decimeter, centimeter)

Hole Machining Methods

The holes differ from each other not only in diameter, but also in the processing method, and are divided into several types.

1) Mounting holes. They are most often made on drilling machines and in terms of processing accuracy they correspond to the eleventh and twelfth qualifications.

2) Smooth and stepped holes of parts having the shape of bodies of revolution. In most cases, they are made on lathes by drilling, reaming, countersinking or boring.

3) Critical openings of body parts. They are manufactured using both universal and specialized equipment and correspond to the seventh qualification and higher.

4) Deep holes having more than five times the length to diameter ratio. They are manufactured on specialized equipment.

5) Shaped and conical holes. They are manufactured using tools with curved or conical cutting edges, as well as copying and boring methods.

6) Profile holes (having a cross-section other than round). They are made by chiseling, stitching or drawing.

Hole diameter for metric thread: size table according to GOST

Despite the fact that cutting internal threads is not a complex technological operation, there are some features of preparation for this procedure. Thus, it is necessary to accurately determine the dimensions of the preparation hole for threading, and also select the right tool, for which special tables of drill diameters for threads are used. For each type of thread, it is necessary to use the appropriate tool and calculate the diameter of the preparation hole.

The thread diameter and through hole must comply with the standards, otherwise the grooves will come out too small and the threaded connection will be unreliable

Cutting technique

Using a hand tap, cutting can be carried out following the following steps:

drill an opening for a thread of the appropriate diameter and depth;
countersink it;
secure the tap in the holder or driver;
align it perpendicular to the working cavity in which cutting will be carried out;
screw the tap with light pressure clockwise into the hole prepared in advance for threading;
Turn the tap back every half turn to cut off the chips.

Thread system

To cool and lubricate surfaces during the cutting process, it is important to use lubricants: machine oil, drying oil, kerosene and the like. Incorrectly selected lubricant can lead to poor cutting results.

The old-fashioned way: how to choose a drill for a tap

Good afternoon, dear readers!

I don’t know if you have ever encountered such a tool as a tap. But, if you work with fasteners, then sooner or later you will encounter this. Even if you are not a builder, you can experience the usefulness of this tool.

So, let's ask Wikipedia: what is a tap?

Metchik
- a tool for cutting internal threads, is a screw with cut straight or helical chip grooves that form cutting edges.

That is, the convenience is that you can drill a hole in the metal and cut a thread there, so that you can then screw in the threaded fasteners.

However, while taps are strong, they are not designed to make a hole. Therefore, you first need to make a hole

.
And here the difficulty lies in the fact that it is important not to make a mistake in the diameter of the drill
.
If you make the hole larger, the thread will turn out small and will quickly become beveled (or there will be no room for the thread at all), if you make it smaller, the tap will lock. And that is not all. The thread pitch on taps can be different, so each step will have its own drill diameter
.

Constantly carrying a table with you that indicates the required drill diameters is also not always convenient. Therefore, I offer you the old-fashioned way of how to select a drill for a tap

Internal thread cutting technology

As mentioned above, before starting work, you need to drill a hole, the diameter of which must exactly fit a 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 poor quality execution, but also to breakage of the tap.

Considering the fact that the tap, when forming threaded grooves, not only cuts the metal, but also pushes it, the diameter of the drill for making threads should be slightly smaller than its nominal diameter. For example, a drill for making M3 threads 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 threads - 5 mm, M8 - 6.7 mm, M10 - 8.5 mm, and for M12 - 10.2.

Table 1. Main diameters of holes for metric threads

Table 2. Diameters of holes for inch threads

All diameters of drills for GOST threads are given in special tables. Such tables indicate the diameters of drills for making threads with both standard and reduced pitches, but it should be borne in mind that holes of different diameters are drilled for these purposes. In addition, if threads are cut in products made of brittle metals (such as cast iron), the diameter of the thread drill obtained from the table must be reduced by one tenth of a millimeter.

You can familiarize yourself with the provisions of GOST regulating 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 that needs to be cut, it is necessary to subtract the value of its pitch. The thread pitch itself, the size of which is used when performing such calculations, can be found out from special correspondence tables. In order to determine what diameter the hole needs to be made using a drill if a three-start tap is used for threading, you must use the following formula:

To = Dm x 0.8, where:

Do is the diameter of the hole that must be made using a drill,

Dm is the diameter of the tap that will be used to process the drilled element.

Scheme of cutting internal threads with a tap

The drivers into which the threaded tap is inserted can have a simple design or be equipped with a ratchet. You should work with such devices with tools fixed in them very carefully. To obtain high-quality and clean threads, rotating the tap clockwise, performed half a turn, must be alternated with turning it one-fourth of a turn against the thread.

The thread will be cut much easier if you use a lubricant during this procedure. The role of such a lubricant when cutting threads in steel products can be played by drying oil, and when processing aluminum alloys - alcohol, turpentine or kerosene. If such technical fluids are not at hand, then ordinary machine oil can be used to lubricate the tap and the thread being cut (however, it has less effect than the substances listed above).

Source: met-all.org

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