What kind of drill do you need to cut an M10 thread - Machine tools, welding, metalworking
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// Table of hole diameters for cutting M1-M68 threads and fine-pitch threads M2x0.25 - M64x4
Table of hole diameters for cutting M1-M68 threads and fine-pitch threads M2x0.25 - M64x4
Table of hole diameters for cutting M1-M68 threads and fine-pitch threads M2x0.25 - M64x4
M
ISO Metric - Coarse Pitch Thread 6N (5N) 1
MF
ISO Metric - Fine Pitch Thread 6H (4H) 1
Many of you have encountered cutting internal threads using a tap, and many have had a question - what diameter should the drill for the thread be, for example M8 or M10.
After all, when cutting threads, the initial task is to drill a hole of a suitable diameter so that the tap does not cut the metal too tightly and at the same time does not dangle.
Therefore, I’ll tell you how you can calculate the correct drill diameter for any metric thread.
In fact, everything is simple, as you know, there are only 2 thread parameters: diameter and pitch. You can also notice (for those who don’t know) that the thread can be standard (with a standard pitch) and any other. For example, the standard thread for 10 mm is 1.5 mm, that is, M10 * 1.5.
But threads 10*1.25 and 10*1 are quite common. The letter M on the thread means that the thread is metric. And sometimes there is a pipe one (read about pipe dies).
Well, in this article we will look at all the nuances of cutting metric threads and, of course, learn how to calculate the diameter of the drill for the thread.
This means, as I already said, we take the diameter and pitch as the basis for the calculations. We simply subtract the thread pitch from the diameter and the resulting figure will be the diameter of the required drill. Let's calculate the diameter of the drill for M8 thread (standard).
8 minus 1.25 (standard pitch) we get 6.75 mm - this is exactly the drill needed to cut an M8 thread. For example, if the thread is 8*1, the drill will have a diameter of 7 mm. I hope everything is clear. I will also provide you with the necessary plate of standard threads (that is, you can find out what the standard pitch is for a certain diameter) and the diameter of the drills for them.
Table of standard threads and drill diameter for them.
threaded drill
Also note: What types of metal turning tools are there and where are they used?
In addition to standard threads, there are steps of 0.75 (for small threads up to M10), 1 mm, 1.25 mm, 2 mm (for large taps and dies).
I hope this article helped you independently calculate the required diameter of the drill for the thread being cut. By the way, do not cut the thread “dry”, but add machine or household oil. This will reduce the load on the tap-die, and it will be much easier to cut.
Diameter of threaded drill (table)
To cut internal threads with a tap. First you need to drill a hole of a certain diameter. The table shows the most popular threads and drill diameters required for drilling holes for threads.
How to find which drill bit for thread without a table?
Suppose you need to cut an M10x1.5 thread.
- Let's find out the nominal thread diameter: 10 mm.
- Find out the nominal thread pitch: 1.5 mm
- Subtract the second value from the first: 10-1.5 = 8.5 mm
- The result is 8.5 mm!
Having mastered this method, you can easily and simply select the right drill bit for cutting threads.
How to use the filter on the website to select a drill bit for threading?
For metal drills, a filter with the “For thread” parameter has been implemented, thanks to which you can find the desired drill in literally 2 mouse clicks:
- Choosing a thread.
- Click “Apply”.
- We get suitable drills.
For which materials are the values indicated in the table?
The indicated hole diameters provide cutting of metric threads in:
- gray cast iron
- carbon steels of ordinary quality
- quality structural steels
- alloyed structural steels
- high alloy steels
- corrosion-resistant, heat-resistant and heat-resistant alloys
- heat-resistant steels
- aluminum casting alloys
- copper
A complete list of threads and diameters can be found in GOST 19257-73 - an official technical document with all the nuances and details.
Before you get started, we recommend that you read the practical tips in the article How to properly cut a thread with a tap. And there you can find suitable coolant for different materials.
Drill and tap hole size charts: metric, inch
Table 1. Correspondence between thread diameters and preparation hole
Before starting work, the tap is inserted into a square shank - a knob. The collars can be regular or ratchet. The carving is done carefully, the first pass is made with a No. 1 tap to the end. Particular attention must be paid to the direction of movement: only clockwise, and some effort must be applied. It is done like this: 1/2 turns along the stroke alternate with 1/4 turns against the screw stroke to destroy the chips.
Thread in inches
Table 2. Hole diameters for inch threads
A couple drops of lubricant will make working on blind threaded holes much easier. Although machine oil is sometimes used as a lubricant, drying oil is optimal for working with steel. With aluminum alloys, it is preferable to use kerosene, alcohol or turpentine. Technical oil can also be used, but with less effect.
Homemade tap for aluminum alloys
To create internal threads in brass or light alloy parts, you can use homemade tools and drills from a regular set. Calibrated steel wire will do. Using a die, an external thread is cut on it, after which the workpiece is hardened. After hardening, it is necessary to release the part to the color of ripe straw. The cutting edges are sharpened using a whetstone or sharpener, after first clamping the part into a collet chuck.
about how internal threads are cut:
Hole diameters for metric threads
Often when repairing a car, and not only, you have to cut a new thread.
And many people don’t know what diameter to drill holes. I decided to give a table from the locksmith's reference book, it might be useful to someone.
The diameters of the holes are given for metric (machine) threads with regular or coarse pitch. You also need to take into account the type of material; if it is hard, for example, steel, then the hole can be drilled 0.1 - 0.2 mm larger.
When cutting threads, do not forget to clear the tap from chips by turning it back after several turns. Use oil.
d, threads(mm) d, drills(mm) d, threads(mm) d, drills(mm)
M1 0.75 M10 8.5 M1.1 0.85 M11 9.5M1.2 0.95 M12 10.2M1.4 1.1 M14 12.0M1.6 1.25 M16 14.0M1.8 1.45 M18 15.4M2 1.6 M20 17.4M2.2 1.75 M22 19.4M2.5 2.05 M24 20.9 M3 2.5 M27 23.9M3.5 2.9 M30 26.4M4 3.3 M33 29.4M4.5 3.8 M36 31.9M5 4.2 M39 34.9M6 5.0 M42 37.4M7 6.0 M45 40.4M8 6.7 M48 42.8
M9 7.7 M52 46.8
When cutting, the thread is first passed with a tap with the 1st number, then with the second number; there are also universal taps, which can be used to cut immediately. When you buy, ask the seller.
Source: https://stanki-info.com/kakoe-nuzhno-sverlo-chtoby-narezat-rezbu-m10/
What kind of drill is needed for M8 thread?
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
Types and parameters of thread
The parameters by which threads are divided into different types are:
- units of diameter (metric, inch, etc.);
- number of thread starts (one-, two- or three-thread);
- the shape in which the profile elements are made (triangular, rectangular, round, trapezoidal);
- direction of rise of turns (right or left);
- location on the product (external or internal);
- surface shape (cylindrical or conical);
- purpose (fastening, fastening and sealing, chassis).
Metric thread parameters
Depending on the above parameters, the following types of thread are distinguished:
- cylindrical, which is designated by the letters MJ;
- metric and conical, designated M and MK respectively;
- pipe, designated by the letters G and R;
- with a round profile, named after Edison and marked with the letter E;
- trapezoidal, designated Tr;
- round, used for installation of sanitary fittings, – Kr;
- thrust and thrust reinforced, marked as S and S45, respectively;
- inch thread, which can also be cylindrical and conical - BSW, UTS, NPT;
- used to connect pipes installed in oil wells.
Thread types according to GOST
Application of the tap
Before you start threading, you need to determine the diameter of the preparation hole and drill it. To facilitate this task, a 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 select the drill size.
To cut metric threads on the inner walls of a hole made with a drill, a tap is used - a screw-shaped tool with cutting grooves, made in the form of a rod, which can have a cylindrical or conical shape. On its side 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.
Tap: design and parameters
In order for the turns of the internal thread to be clean and neat, and for 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 treated.
That is why for this purpose they use either taps, 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 sufficiently perform machining of threaded holes is a set consisting of two taps - rough and finishing. The first one cuts a thin layer of metal from the walls of the hole for cutting metric threads and forms a shallow groove on them, the second one not only deepens the formed groove, but also cleans it.
Types of thread taps and their differences
Minimum set of taps
Combination two-pass taps or sets consisting of two tools are used for tapping small diameter holes (up to 3 mm). To machine holes for larger metric threads, you must use a combination three-pass tool or a set of three taps.
To manipulate the tap, a special device is used - a wrench. The main parameter of such devices, which can have different designs, is the size of the mounting hole, which must exactly match the size of the tool shank.
Some types of tap drivers
When using a set of three taps that differ both in their design and geometric parameters, the sequence of their use must be strictly observed. They can be distinguished from each other both by special marks applied to the shanks and by design features.
- The tap, with which the hole for cutting metric threads is processed first, has the smallest diameter among all the tools in the set and cutting teeth, the upper part of which is heavily cut off.
- The second tap has a shorter fence and longer combs. Its working diameter is intermediate between the diameters of the other tools in the set.
- The third tap, with which the hole for cutting metric threads is processed last, is characterized by full ridges of cutting teeth and a diameter that must exactly match the size of the thread being formed.
Source: https://moreremonta.info/strojka/kakoe-sverlo-nado-pod-rezbu-m8/
Repair and restoration of broken threads
Our company does not restore threads. This article is intended solely to introduce you to the thread restoration process. In our stores you can buy fittings (threaded inserts), drills, taps, thread restoration kits.
The information is intended for persons carrying out repairs in a personal garage and car repair shops. In accordance with this, the text is structured and recommendations are given. The use of this method in manufacturing enterprises involves the use of specific tools and devices, and other technology.
Damaged threads can be completely restored using the following technology:
1. Drill the threaded hole to the diameter indicated in the table below
2. special profile
thread in it 3. Screw a spiral repair insert (a durable stainless steel sleeve) into the resulting thread using a special tool.
After such an operation, the thread becomes stronger than the original one in good condition. This effect is especially noticeable when the carving is made in a soft material such as aluminum. When a bolt (stud) breaks off in a threaded insert, there is no “biting” effect. A broken bolt (stud) can be easily removed.
Watch a video of how the threaded insert is used
What capabilities do threaded inserts have?
This method is especially relevant for restoring threaded holes in body parts of automobile engines, for example, a spark plug hole. The candle thread becomes very durable and reliable.
Threaded insert screwed in
Threaded insert screwed in
If the thread for a stud is broken, sometimes they drill it out and cut the thread to the next size. In this case, you have to use a stepped stud of unknown origin and dubious quality. And not every stepped hairpin can be found at the right time. If you repair the hole using a threaded insert, you still have the option of using a standard, branded pin.
Another use for repair threaded inserts is in brass exhaust manifold nuts. The result is a nut that combines a very strong thread and the property of not “sticking” to the studs.
Owners of some foreign cars should pay attention to the possibility of replacing the M12 x 1.5 thread with an M12 x 1.25 thread. It often happens that a bolt with such a thread is damaged, and it is almost impossible to find it in a retail chain in your city (we have such bolts in our store).
A turner will not turn out a decent bolt, because... The threads on factory bolts are formed by pressure (knurling), which provides the necessary strength.
And on a lathe, the thread is made with a cutter, while the fibers of the steel bar are cut and the threads cannot bear the required load.
If you replace the thread in the body part with the more common in Russia M12 x 1.25, it becomes possible to select a bolt of the required size and strength from the assortment of Russian and European manufacturers of automotive fasteners presented in our catalog.
– how the threaded insert works, demonstration
What tools are used to restore threads?
1. Drill
The drill diameter is selected from the table.
Table for selecting drill diameters for the most common threaded holes
| No. | Repairable thread sizes | Drill diameter |
| 1 | M5 x 0.8 | 5,2 |
| 2 | M6 x 1 | 6,3 |
| 3 | M8 x 1 | 8,3 |
| 4 | M8 x 1.25 | 8,4 |
| 5 | M10 x 1 | 10,25 |
| 6 | M10 x 1.25 | 10,4 |
| 7 | M10 x 1.5 | 10,5 |
| 8 | M12 x 1.25 | 12,25 |
| 9 | M12 x 1.5 | 12,5 |
| 10 | M12 x 1.75 | 12,5 |
| 11 | M14 x 2 | 14,5 |
| 12 | M14 x 1.5 | 14,5 |
| 13 | M14 x 1.25 (for a candle) | 14,25 |
2.Tap
To repair the spark plug hole, a stepped tap is recommended. It is centered in the old hole with its lead-in part, and immediately cuts a new thread, bypassing the drilling operation.
A stepped tap significantly reduces the risk of damage to the spark plug hole, but it is noticeably more expensive than a regular tap.
To lengthen the tap when repairing a deeply recessed spark plug hole, you can use a regular 10-point twelve-sided socket with the appropriate tool.
3.Spindle (tool for screwing the insert)
The working part of the spindle is similar to the threaded part of a bolt, with a hook at the end.
4.Repair insert
The insert is a diamond-shaped spiral.
At one end there is a leash, behind which the insert is rotated by a spindle.
The inserts have different lengths.
Description of thread restoration technology
Attention: this technology is used for repairing threaded holes in domestic and garage conditions.
1. Drill a hole.
Periodically remove the drill from the hole and dip its end into a container of motor oil. A minimum drill speed is desirable. 2. Use a tap to cut the thread for the insert. During operation, it is necessary to constantly supply motor oil to the cutting zone, for example from a medical syringe, especially when working with aluminum.
Otherwise, the thread may turn out to be “torn”, rough, and aluminum will stick to the tap. If the hole is blind, it is better to use a lubricant, such as Litol, instead of engine oil. You need to coat the working part of the tap with it so that the chips do not fall into the hole, but stick to the tap.3. Wash the resulting thread with kerosene.
4.
Place the insert on the spindle, engage the leader and the hook.
You need to keep in mind that the insert is slightly larger than the spindle; it does not sit tightly on it, but dangles freely. When screwed into the hole, the insert is compressed and thereby secured in the hole.
Screw the insert until its rear end is 1/4 of the thread pitch deep into the hole. After this, unscrew the spindle and break off the insert driver by pressing on it with a suitable rod. To do this, there is a risk on the turn behind the leash, along which the leash will break off.
Note: When using a stepped tap, point 1 is excluded.
Our company does not restore threads. This article is intended solely to introduce you to the thread restoration process. In our stores you can buy fittings (threaded inserts), drills, taps, thread restoration kits.
Source: https://avto-bolt.ru/remont-rezby/
Selecting a drill according to the diameter of the thread: special tables and cutting features - SibNovStroy
Any detachable type connection must have a thread. It is worth noting that all hardware with external threads, bolts in particular, can be purchased anywhere: in a construction supermarket or at the market. But with internal threads everything is much more complicated. It should be cut with your own hands or using special machines.
Today we will tell you how to correctly select drills of a particular diameter for a specific thread, and you can also familiarize yourself with the table of these diameters.
The need to select drills for threading
To make your own internal thread, take your workpiece and drill a hole in it that will match the diameter of the tool that is intended for cutting. And each of these holes must strictly correspond to the size of the tool. This is why you need to carefully select the diameter of the drill according to the thread.
Today there are drills on sale with different diameters and sizes. Starting from a minimum size of 0.5 mm and ending with large conical drills measuring about 0.05 mm. Depending on the type of work performed, holes of different diameters can be made by drilling to suit certain needs.
Parameters for selecting a drill for threading: table
If you need to drill a hole with a large diameter, you will need to take a special machine, where the drills are equipped with conical tails, but ordinary drills are equipped with cylindrical tails. On a large drill, the cone has a fifth size. Thus, the parameters of the cone directly depend on the diameter of the drill; the larger the diameter of the drill, the larger the cone is needed. For example:
- diameter from 6 to 10 mm;
- the required cone size is from 11 to 22 mm.
You can select the drill diameter for a particular thread as accurately as possible using a special size selection table.
If there is a need to create an internal thread, the hole diameter should be selected according to the thread diameter and thread pitch parameters. This data in the tables is designated as M8×1 , where:
- M is a metric thread;
- the number is the thread pitch;
- if it is simply M8 and without numbers, then you need to use a standard large step. This parameter step is the most common and is adjusted according to standards for most drill sizes.
Diameters require selection of the appropriate hole size. The table includes a list of the most common sizes that you usually have to deal with in everyday life when performing certain jobs.
Thread classification
Externally, the thread looks like a helical groove with a constant cross-section.
We have already mentioned these types earlier. Threaded connections are used everywhere. They are needed so that the part can rotate through translational movements. Without threaded connections, it is difficult to imagine the normal operation of mechanisms or complex machines. They can also be single-pass or multi-pass.
If we talk about classification by size , then it comes in the following types:
- metric;
- inch;
- pipe
Metric threads are distinguished by their special triangular profile, the angle of which is 60 degrees. All thread parameters are calculated in millimeters. If the thread pitch is large, then, as already mentioned, we have a number and a letter designation.
The number indicates the size of the outer diameter of the thread, according to which you can select a particular drill. Technical drawings must certainly include characteristics of the thread or its analogues.
If a metric thread needs to be represented with a small non-standard pitch, then you need to add a number that indicates the pitch.
Another profile angle value is specific to an inch-type threaded connection. This angle can be equal to 55 degrees , and the size of the hole is calculated in inches, the pitch varies by the number of threads.
And the pipe threaded type differs from others in its initial diameter, which depends directly on the size of the pipe hole. In this case, cutting is carried out only externally.
Features of thread cutting
Various equipment is used for thread cutting, for example:
- drill type machine;
- turning park;
- various cutting devices.
In this case, cutting can be done either mechanically or manually. For example, for internal use you can use special threaded taps, and for external use - dies. Taps, like drills, are selected depending on the diameter of the hole. They are divided into the following categories:
- inch;
- metric;
- pipe
Basically, sets of hand taps consist of three devices, two of which are needed for preliminary work, and the last one is a finishing tool, with the help of which the final shape of the thread is made and adjusted to certain dimensions. The taps have numbers. If the die holder is supplied with not three, but two devices, then the first is preliminary, and the second is finishing. Taps are made on the basis of high-alloy steel.
External threads are obtained by using a die. These tools can be round or prismatic in shape. For round dies use a knob .
Methods for producing internal threads
To make a hole where you will need to tap, you must first select the correct size drill bit.
To use a tap, its hole must be processed with a countersink until the desired degree of cleanliness is obtained. When cutting, the metal is gradually squeezed out.
The size of the drill should be slightly larger than the internal threaded diameter of this tool.
When cutting, the hardness of the metal does not greatly affect the diameter of the hole. But if a low thread material is used, the diameter of the hole can change significantly.
So, if the size of the hole and the internal diameter of the drill exactly correspond to each other, then during cutting the material is squeezed out, and its excess acts on the teeth of the tap.
When heated, the chips stick, as a result of which the tap may break and the threads will have torn threads .
When working with drills and threaded connections, you need to very carefully select the parameters so that the work is ultimately completed efficiently. Special tables will help you with this, indicating the parameters for a particular thread and other valuable tips.
Source: https://sibnovostroy.ru/oborudovanie/podbor-sverla-po-diametru-k-rezbe-spetsialnye-tablitsy-i-osobennosti-rezki.html
