Screws, bolts and studs are the most common external threads. Most often, they fall into the hands of a home master ready-made. But it happens that you need to make some tricky bolt or non-standard stud. The blank for such a part is a rod, the diameter of which must correspond to the thread being cut.
The diameter of the rod for external threading depends on the nominal diameter of the thread and the size of the thread pitch. All this information is usually indicated on the detail drawing as the designation M10 × 1.5. The letter "M" denotes a metric thread, the number after the letter is the nominal diameter, the number after the sign "x" is the thread pitch. When using the main (large) step, it may not be indicated. Main thread pitch defined by the standard and is the most preferred.
When choosing the diameter of the rod for external threads, the same principles are followed as when choosing holes for internal threads. Determined that best quality thread is obtained if the diameter of the rod is slightly less than the nominal diameter of the thread being cut. When cutting, the metal is squeezed out a little and the thread profile is complete.
If the diameter of the rod is much less than required, then the tops of the threads will be cut off, if it is larger, then the die simply will not screw onto the rod or break during operation.
For each combination of diameter and thread pitch, there is optimal diameter rod. The easiest way to determine this diameter is from the table, which shows the most common threads that can be encountered. House master. Bold type in the table indicates the main thread pitch for each nominal diameter.
Thread | thread pitch | Rod diameter nominal (limiting) |
M2 | 0,4 | 1,93-1,95 (1,88) |
0,25 | 1,95-1,97 (1,91) | |
M2.5 | 0,45 | 2,43-2,45 (2,37) |
0,35 | 2,45-2,47 (2,39) | |
M3 | 0,5 | 2,89-2,94 (2,83) |
0,35 | 2,93-2,95 (2,89) | |
M4 | 0,7 | 3,89-3,94 (3,81) |
0,5 | 3,89-3,94 (3,83) | |
M5 | 0,8 | 4,88-4,94 (4,78) |
0,5 | 4,89-4,94 (4,83) | |
M6 | 1 | 5,86-5,92 (5,76) |
0,75 | 5,88-5,94 (5,79) | |
0,5 | 5,89-5,94 (5,83) | |
M8 | 1,25 | 7,84-7,90 (7,73) |
1 | 7,86-7,92 (7,76) | |
0,75 | 7,88-7,94 (7,79) | |
0,5 | 7,89-7,94 (7,83) | |
M10 | 1,5 | 9,81-9,88 (9,69) |
1 | 9,86-9,92 (9,76) | |
0,5 | 9,89-9,94 (9,83) | |
0,75 | 9,88-9,94 (9,79) | |
M12 | 1,75 | 11,80-11,86 (11,67) |
1,5 | 11,81-11,88 (11,69) | |
1,25 | 11,84-11,90 (11,73) | |
1 | 11,86-11,92 (11,76) | |
0,75 | 11,88-11,94 (11,79) | |
0,5 | 11,89-11,94 (11,83) | |
M14 | 2 | 13,77-13,84 (13,64) |
1,5 | 13,81-13,88 (13,69) | |
1 | 13,86-13,92 (13,76) | |
0,75 | 13,88-13,94 (13,79) | |
0,5 | 13,89-13,94 (13,83) | |
M16 | 2 | 15,77-15,84 (15,64) |
1,5 | 15,81-15,88 (15,69) | |
1 | 15,86-15,92 (15,76) | |
0,75 | 15,88-15,94 (15,79) | |
0,5 | 15,89-15,94 (15,83) | |
M18 | 2 | 17,77-17,84 (17,64) |
1,5 | 17,81-17,88 (17,69) | |
1 | 17,86-17,92 (17,76) | |
0,75 | 17,92-17,94 (17,86) | |
M20 | 2,5 | 19,76-19,84 (19,58) |
1,5 | 19,81-19,88 (19,69) | |
1 | 19,86-19,92 (19,76) | |
0,75 | 19,88-19,94 (19,79) | |
0,5 | 19,89-19,94 (19,83) |
The main tool for cutting external threads is a die. The most commonly used round solid dies in the form of a hardened steel nut.
To form cutting edges, the thread of the die is crossed by through longitudinal holes, which also provide chip exit. To facilitate entry, the extreme threads of the thread have an incomplete profile. To rotate the plate, use die holder- a tool with a socket for a die and long handles. There are also split and sliding (klupp) dies, but this is rare in the home workshop.
To reduce friction and obtain a clean thread on steel rods, a lubricant is used - mineral oil or kerosene, on copper - turpentine. At the end of the rod, to facilitate entry, a chamfer must be made with a width not less than the thread pitch.
Before cutting a thread, it is necessary to select the diameter of the workpiece for this thread.
slicing die thread, it must be borne in mind that when forming a thread profile metal products, especially steel, copper, etc., stretches and the product increases. As a result, the pressure on the surface of the die increases, which leads to heating and adhesion of metal particles, so the thread may turn out to be torn.
The same considerations should be followed when choosing a shank diameter for external threads as when choosing holes for internal threads. The practice of cutting external threads shows that the best thread quality can be obtained if the diameter of the rod is somewhat smaller than the outer diameter of the thread being cut. If the diameter of the rod is less than required, then the thread will be incomplete; if more, then the die will either not be able to be screwed onto the rod and the end of the rod will be damaged, or during operation, the teeth of the die may break due to overload, and the thread will be torn off.
In table. 27 shows the diameters of the rods used when cutting threads with dies.
Table 27 Diameters of rods for threading when cutting with dies
The diameter of the workpiece should be 0.3-0.4 mm less than the outer diameter of the thread.
When threading with a die, the rod is fixed in a vice so that the end of the vise protruding above the level of the jaws is 20-25 mm longer than the length of the part to be cut. To ensure plunging, a chamfer is sawn at the upper end of the rod. Then, a die fixed in the die is placed on the rod and the die is rotated with a little pressure so that the die cuts by about 0.2-0.5 mm. After that, the cut part of the rod is lubricated with oil and the screw is rotated in exactly the same way as when working with a tap, that is, one or two turns to the right and half a turn to the left (Fig. 152, b).
Rice. 152. Reception of threading with a die (b)
To prevent marriage and breakage of the teeth, it is necessary that the die enters the rod without distortion.
Checking the cut internal threads is carried out with threaded plug gauges, and the outer thread - with threaded micrometers or threaded ring gauges.
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.
The parameters by which the thread is divided into different types, are:
Depending on the above parameters, there are the following types threads:
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 sets consisting of two tools are used for threading in holes with small diameters (up to 3 mm). Larger metric holes require 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 may have different design, 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.
Taps are used primarily for threading metric threads. Much less frequently than metric taps are used for processing the inner walls of pipes. They are called pipe pipes in accordance with their purpose, and they can be distinguished by the letter G present in their marking.
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.
Given 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 drill bit 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.
This table will help you understand the cutting of metric threads and possibly reduce waste. Tabular values can be useful to machine operators, shop foremen, engineers.
The diameters of the rods for cutting metric threads are regulated by GOST 16093-2004.
Nominal thread diameter d | Thread Pitch | Threaded rod diameter with tolerance field | ||||||
4h | 6g | 6e | 6e; 6g | 8g | ||||
Nominal diameter | Limit deviation | Nominal diameter | Limit deviation | Nominal diameter | Limit deviation | |||
1,0 | 0,25 | 0,97 | -0,03 | 0,95 | - | -0,04 | - | - |
1,2 | 0,25 | 1,17 | 1,15 | - | - | - | ||
1,4 | 0,3 | 1,36 | 1,34 | - | - | - | ||
1,6 | 0,35 | 1,55 | 1,53 | - | - | - | ||
2 | 0,4* | 1,95 | -0,04 | 1,93 | - | -0,05 | - | - |
0,25 | 1,97 | -0,03 | 1,95 | - | -0,04 | - | - | |
2,5 | 0,45 | 2,45 | -0,04 | 2,43 | - | -0,06 | - | - |
3 | 0,5* | 2,94 | 2,92 | 2,89 | - | - | ||
0,35 | 2,95 | -0,03 | 2,93 | - | -0,04 | - | - | |
4 | 0,7* | 3,94 | -0,06 | 3,92 | 3,89 | -0,08 | - | - |
0,5 | 3,94 | -0,04 | 3,92 | 3,89 | -0,06 | - | - | |
5 | 0,8* | 4,94 | -0,07 | 4,92 | 4,88 | -0,10 | 4,92 | -0,18 |
0,5 | 4,94 | -0,04 | 4,92 | 4,89 | -0,06 | - | - | |
6 | 1* | 5,92 | -0,07 | 5,89 | 5,86 | -0,10 | 5,89 | -0,20 |
0,75 | 5,94 | -0,06 | 5,92 | 5,88 | -0,09 | - | - | |
0,5 | 5,94 | -0,04 | 5,92 | 5,89 | -0,06 | - | - | |
8 | 1,25* | 7,90 | -0,08 | 7,87 | 7,84 | -0,11 | 7,87 | -0,24 |
1 | 7,92 | -0,07 | 7,89 | 7,86 | -0,10 | 7,89 | -0,20 | |
0,75 | 7,94 | -0,06 | 7,92 | 7,88 | -0,09 | - | - | |
0,5 | 7,94 | -0,04 | 7,92 | 7,89 | -0,06 | - | - | |
10 | 1,5* | 9,88 | -0,09 | 9,85 | 9,81 | -0,12 | 9,85 | -0,26 |
1 | 9,92 | -0,07 | 9,89 | 9,86 | -0,10 | 9,89 | -0,20 | |
0,5 | 9,94 | -0,04 | 9,92 | 9,89 | -0,06 | - | - | |
0,75 | 9,94 | -0,06 | 9,92 | 9,88 | -0,09 | - | - | |
12 | 1,75* | 11,86 | -0,10 | 11,83 | 11,80 | -0,13 | 11,83 | -0,29 |
1,5 | 11,88 | -0,09 | 11,85 | 11,81 | -0,12 | 11,85 | -0,26 | |
1,25 | 11,90 | -0,08 | 11,87 | 11,84 | -0,11 | 11,87 | -0,24 | |
1 | 11,92 | -0,07 | 11,89 | 11,86 | -0,10 | 11,89 | -0,20 | |
0,75 | 11,94 | -0,06 | 11,92 | 11,88 | -0,09 | - | - | |
0,5 | 11,94 | -0,04 | 11,92 | 11,89 | -0,06 | - | - | |
14 | 2* | 13,84 | -0,10 | 13,80 | 13,77 | -0,13 | 13,80 | -0,29 |
1,5 | 13,88 | -0,09 | 13,85 | 13,81 | -0,12 | 13,85 | -0,26 | |
1 | 13,92 | -0,07 | 13,89 | 13,86 | -0,10 | 13,89 | -0,20 | |
0,75 | 13,94 | -0,06 | 13,92 | 13,88 | -0,09 | - | - | |
0,5 | 13,94 | -0,04 | 13,92 | 13,89 | -0,06 | - | - | |
16 | 2* | 15,84 | -0,10 | 15,80 | 15,77 | -0,13 | 15,80 | -0,29 |
1,5 | 15,88 | -0,09 | 15,85 | 15,81 | -0,12 | 15,85 | -0,26 | |
1 | 15,92 | -0,07 | 15,89 | 15,86 | -0,10 | 15,89 | -0,20 | |
0,75 | 15,94 | -0,06 | 15,92 | 15,88 | -0,09 | - | - | |
0,5 | 15,94 | -0,04 | 15,92 | 15,89 | -0,06 | - | - | |
18 | 2* | 17,84 | -0,10 | 17,80 | 17,77 | -0,13 | 17,80 | -0,29 |
1,5 | 17,88 | -0,09 | 17,85 | 17,81 | -0,12 | 17,85 | -0,26 | |
1 | 17,92 | -0,07 | 17,89 | 17,86 | -0,10 | 17,89 | -0,20 | |
0,75 | 17,94 | -0,04 | 17,94 | 17,92 | -0,06 | - | - | |
20 | 2,5* | 19,84 | -0,13 | 19,80 | 19,76 | -0,18 | 19,80 | -0,37 |
1,5 | 19,88 | -0,09 | 19,85 | 19,81 | -0,12 | 19,85 | -0,26 | |
1 | 19,92 | -0,07 | 19,89 | 19,86 | -0,10 | 19,89 | -0,20 | |
0,75 | 19,94 | -0,06 | 19,92 | 19,88 | -0,09 | - | - | |
0,5 | 19,94 | -0,04 | 19,92 | 19,89 | -0,06 | - | - |
The standard metric thread pitch is indicated(*)
Pipe thread is a group of standards designed to connect and seal various types of structural elements using pipe threads. The quality of the grooving work has a great influence on the reliability of the connection and the structure obtained in this way. Particular attention should be paid to the correlation of the thread with the axis of the pipe on which it is applied.
When threading by hand using a die, the concentricity is far from ideal, which can affect the reliability and quality of the connection. As for the use of tools such as a lathe or thread-cutting machine, the application threading heads with precise threading knife, then the indicators of the applied thread are comparable with the theoretical values.
The ROTHENBERGER concern manufactures threading machines, threading dies, heads, knives that provide work with high precision. All equipment fully complies with international standards in this area.
Also known as the Whitward carving ( BSW (British Standard Whitworth)). Applies this species for organizing cylindrical threaded connections. Also used in cases where an internal cylindrical thread is connected to an external conical thread (GOST 6211-81).
Thread parameters
Symbol example:
G - designation of the profile shape (cylindrical pipe thread);
G1 1 / 2 - conditional passage (measured in inches);
A - accuracy class (may be A or B).
To designate a left-hand thread, the LH index is used (example: G1 1 / 2 LH-B-40 - cylindrical pipe thread, 1 1 / 2 - nominal bore in inches, accuracy class B, make-up length 40 millimeters).
The thread pitch can have one of four values:
Table 1
The main dimensions of cylindrical pipe threads are determined by GOST 6357-81 (BSP). It should be remembered that the thread size in this case conditionally characterizes the lumen of the pipe, despite the fact that in fact outside diameter substantially more.
table 2
Thread size designation | P step | Thread diameters | |||
---|---|---|---|---|---|
Row 1 | Row 2 | d=D | d2=D2 | d1=D1 | |
1/16" | 0,907 | 7,723 | 7,142 | 6,561 | |
1/8" | 9,728 | 9,147 | 8,566 | ||
1/4" | 1,337 | 13,157 | 12,301 | 11,445 | |
3/8" | 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 | 29,039 | 27,877 | ||
1" | 2,309 | 33,249 | 31,770 | 30,291 | |
1.1/8" | 37,897 | 36,418 | 34,939 | ||
1.1/4" | 41,910 | 40,431 | 38,952 | ||
1.3/8" | 44,323 | 42,844 | 41,365 | ||
1.1/2" | 47,803 | 46,324 | 44,845 | ||
1.3/4" | 53,746 | 52,267 | 50,788 | ||
2" | 59,614 | 58,135 | 56,656 | ||
2.1/4" | 65,710 | 64,231 | 62,762 | ||
2.1/2" | 75,184 | 73,705 | 72,226 | ||
2.3/4" | 81,534 | 80,055 | 78,576 | ||
3" | 87,884 | 86,405 | 84,926 | ||
3.1/4" | 93,980 | 92,501 | 91,022 | ||
3.1/2" | 100,330 | 98,851 | 97,372 | ||
3.3/4" | 106,680 | 105,201 | 103,722 | ||
4" | 113,030 | 111,551 | 110,072 | ||
4.1/2" | 125,730 | 124,251 | 122,772 | ||
5" | 138,430 | 136,951 | 135,472 | ||
5.1/2" | 151,130 | 148,651 | 148,172 | ||
6" | 163,830 | 162,351 | 160,872 |
d - outer diameter of the outer thread (pipe);
D - outer diameter of the internal thread (coupling);
D1 - internal diameter of the internal thread;
d1 - internal diameter of the external thread;
D2 - the average diameter of the internal thread;
d2 is the average diameter of the external thread.
It is used to organize pipe conical connections, as well as to connect the inner cylindrical and outer taper thread(GOST 6357-81). Based on BSW, compatible with BSP.
The sealing function in connections using BSPT is performed by the thread itself (due to its collapse at the junction when the fitting is screwed in). Therefore, the application of BSPT should always be accompanied by the use of a sealant.
This type of thread is characterized by the following parameters:
designation according to the shape of the profile - inch thread with a taper (profile in the form of an isosceles triangle with an angle at the apex of 55 degrees, cone angle φ=3°34′48").
When designating, an alphabetic index of the thread type is used (R for external and Rc for internal) and a numerical indicator of the nominal diameter (for example, R1 1/4 - conical pipe thread with a nominal diameter of 1 1/4). The index LH is used to designate a left-hand thread.
Thread parameters
Inch thread with taper 1:16 (taper angle φ=3°34′48"). Profile angle at apex 55°.
Symbol: letter R for external thread and Rc for internal ( GOST 6211-81- Basic norms of interchangeability. Pipe thread conical.), numerical value of the nominal diameter of the thread in inches (inch), the letters LH for the left thread. For example, a thread with a nominal diameter of 1.1/4 is referred to as R 1.1/4.
Table 3
Thread size designation, pitches and nominal values of the outer,
average and internal diameters of pipe taper thread (R), mm
Designation size carving | P step | Thread length | Main thread diameter plane |
|||
---|---|---|---|---|---|---|
working | From the end pipes up basic plane | Outer d=D | Average d2=D2 | Interior d1=D1 |
||
1/16" | 0,907 | 6,5 | 4,0 | 7,723 | 7,142 | 6,561 |
1/8" | 6,5 | 4,0 | 9,728 | 9,147 | 8,566 | |
1/4" | 1,337 | 9,7 | 6,0 | 13,157 | 12,301 | 11,445 |
3/8" | 10,1 | 6,4 | 16,662 | 15,806 | 14,950 | |
1/2" | 1,814 | 13,2 | 8,2 | 20,955 | 19,793 | 18,631 |
3/4" | 14,5 | 19,5 | 26,441 | 25,279 | 24,117 | |
1" | 2,309 | 16,8 | 10,4 | 33,249 | 31,770 | 30,291 |
1.1/4" | 19,1 | 12,7 | 41,910 | 40,431 | 38,952 | |
1.1/2" | 19,1 | 12,7 | 47,803 | 46,324 | 44,845 | |
2" | 23,4 | 15,9 | 59,614 | 58,135 | 56,565 | |
2.1/2" | 26,7 | 17,5 | 75,184 | 73,705 | 72,226 | |
3" | 29,8 | 20,6 | 87,884 | 86,405 | 84,926 | |
3.1/2" | 31,4 | 22,2 | 100,330 | 98,851 | 97,372 | |
4" | 35,8 | 25,4 | 113,030 | 111,551 | 110,072 | |
5" | 40,1 | 28,6 | 138,430 | 136,951 | 135,472 | |
6" | 40,1 | 28,6 | 163,830 | 162,351 | 160,872 |
Metric threads. Rod diameters and tolerances for metric thread M3-M50, performed by dies. Drill diameters M1-M10 for drilling holes for metric threads. Cutting threads with dies and taps.
Table 1. Diameters of rods for metric threads made with dies
Diameters | Tolerances for rod diameter |
Diameters | Tolerances for rod diameter |
||
carving | rod | carving | rod | ||
Coarse thread | |||||
3 | 2,94 | -0,06 | 12 | 11,88 | -0,12 |
3,5 | 3,42 | -0,08 | 16 | 15,88 | -0,12 |
4 | 3,92 | -0,08 | 18 | 17,88 | -0,12 |
4,5 | 4,42 | -0,08 | 20 | 19,86 | -0,14 |
5 | 4,92 | -0,08 | 22 | 21,86 | -0,14 |
6 | 5,92 | -0,08 | 24 | 23,86 | -0,14 |
7 | 6,90 | -0,10 | 27 | 26,86 | -0,14 |
8 | 7,90 | -0,10 | 30 | 29,86 | -0,14 |
9 | 8,90 | -0,10 | 33 | 32,83 | -0,17 |
10 | 9,90 | -0,10 | 36 | 35,83 | -0,17 |
11 | 10,88 | -0,12 | 39 | 38,83 | -0,17 |
Thread with fine pitch | |||||
4 | 3,96 | -0,08 | 24 | 23,93 | -0,14 |
4,5 | 4,46 | -0,08 | 25 | 24,93 | -0,14 |
5 | 4,96 | -0,08 | 26 | 25,93 | -0,14 |
6 | 5,96 | -0,08 | 27 | 26,93 | -0,14 |
7 | 6,95 | -0,10 | 28 | 27,93 | -0,14 |
8 | 7,95 | -0,10 | 30 | 29,93 | -0,14 |
9 | 8,95 | -0,10 | 32 | 31,92 | -0,17 |
10 | 9,95 | -0,10 | 33 | 32,92 | -0,17 |
11 | 10,94 | -0,12 | 35 | 34,92 | -0,17 |
12 | 11,94 | -0,12 | 36 | 35,92 | -0,17 |
14 | 13,94 | -0,12 | 38 | 37,92 | -0,17 |
15 | 14,94 | -0,12 | 39 | 38,92 | -0,17 |
16 | 15,94 | -0,12 | 40 | 39,92 | -0,17 |
17 | 16,94 | -0,12 | 42 | 41,92 | -0,17 |
18 | 17,94 | -0,12 | 45 | 44,92 | -0,17 |
20 | 19,93 | -0,14 | 48 | 47,92 | -0,17 |
22 | 21,93 | -0,14 | 50 | 49,92 | -0,17 |
Table 2. Drill diameters for drilling holes for metric threads
Outside diameter threads, mm |
Drill diameter (mm) for | |
Cast iron, bronze | Steel, brass | |
1 | 0,75 | 0,75 |
1,2 | 0,95 | 0,95 |
1,6 | 1,3 | 1,3 |
2 | 1,6 | 1,6 |
2,5 | 2,2 | 2,2 |
3 | 2,5 | 2,5 |
3,5 | 2,9 | 2,9 |
4 | 3,3 | 3,3 |
5 | 4,1 | 4,2 |
6 | 4,9 | 5 |
7 | 5,9 | 6 |
8 | 6,6 | 6,7 |
9 | 7,7 | 7,7 |
10 | 8,3 | 8,4 |
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