Drill- a very popular tool not only in various fields of activity, but also in everyday life, in daily use. A very wide range of drills from different manufacturers sometimes just stuns the average buyer. Let's find out how to choose a drill for metal and which manufacturer's drills should be preferred.
Drills for metal
Metal drills are used to cut holes in non-alloyed and alloyed steel, cast iron, non-ferrous metal, etc. This type of drill has a helical shape, hence the appropriate name, twist drills. Twist drills have two longitudinal flutes that evacuate chips while drilling. There are several types of twist drill shank - conical, hex and cylindrical. The conical ones are inserted directly into the machine, the cylindrical ones are inserted into a special cartridge.
If you are interested in the question: “Which metal drills are better?” Pay attention to the color when choosing a drill, it will say a lot about the quality.
Choosing a quality drill by color
If the drill is black, it means that superheated steam was used in the finishing. Such a drill has increased wear resistance.
If stress relief was used during finishing, the drill will have a slight golden hue.
High-quality metal drills have a bright golden hue - a layer of titanium nitride is applied to the drill. These are very high quality tools, have high strength and reduced friction. A little more expensive than the rest, but also superior in quality to the rest.
The regular gray drill (cheapest) has no processing. The minimum price and the same service life, and nothing more.
Look at the photo of metal drills to finally remember the types of colors and their inherent characteristics.
Drill marking for metal
The marking depends on the diameter. Drills up to 2mm are not marked, on drills up to 3mm, the steel grade and diameter are indicated, thicker drills may carry information about the manufacturer and accuracy class.
Drill marking begins with the letter P - high speed steel. In the form of a numerical value, the content of various substances in the alloy is also indicated. For example, K6 is part of cobalt, M3 is molybdenum content. On imported drills, the marking is in the form of HSS or Din values.
Having learned the characteristics and types of drills, you now know exactly how to choose a drill for metal. We will only give examples of high-quality drills that are widely used by professionals.
RUKO twist drills for metal TL 3000 (HSS-G, HSS-E, HSS-G TiN, HSS-G TiAlN)
Drills for metal ruko model range TL 3000 is known to consumers as a high quality material at an affordable price. Drill diameter- from 3mm (have a cross sharpening according to DIN 1412 C). The drills have a sharpening angle of 130°. Depending on the specific model, they are coated with titanium nitride, titanium aluminum nitride, etc.
Multi-purpose drills, great for large drilling depths. Best suited for materials that form long and medium chips.
HSS-G drills perfectly drill carbon and alloy steels, cast iron, copper and aluminum alloy.
HSS-E drills stainless and acid-resistant steel, as well as copper and aluminum alloys in addition to carbon and alloy steel.
HSS-G TiN and HSS-G TiAlN are suitable for all of the above materials as well as titanium alloy.
Drills for metal BOSCH HSS-CO
BOSCH drills of the HSS-CO model range are made of high speed steel according to all standards. The drills have an oxide coating that quickly removes chips during drilling. The standard 135° chisel-shaped edge with mesh grinding is suitable for almost all types of work.
Alloying with cobalt improves the strength and heat resistance of the drill. The tensile strength is 1000N/mm2, which allows it to work with most types of steel and alloys, as well as cope with heavy production tasks.
Accuracy class h8 provides the necessary exposure of the outer diameter.
HAISSER metal drills with titanium coating
One of the most powerful drills that are used under extreme load in domestic and industrial environments. Drills have cross-shaped sharpening. Titanium coating provides maximum cooling, which allows you to work in the most difficult conditions. The main application of the drill is found in the field of industrial and complex work. Angle 135 with mesh polishing. Titanium nitride coating gives minimal friction and reduced cold welding. Due to their high wear resistance, the drills have a unique long term services.
Drill for metal ZUBR "Cobalt"
Drill for metal ZUBR is made of R6M5K5 high-speed steel. Has a cylindrical shank. According to the strength class, it belongs to category A1. The use of cobalt (5%) in manufacturing gives this drill extra strength and wear resistance.
Cobalt drills are used for drilling non-ferrous metals, stainless steel, hard-to-machine tough steel, etc. Drills are made in accordance with GOST 10902-77. The price of the ZUBR "Cobalt" drills is quite consistent with the quality of the product, so many buyers make a choice in favor of this product.
Almost every head of the family has a minimum supply necessary tools for various purposes. And one of the most common jobs is drilling. And for some, this is a regular need. But according to the universal “law”, at the right moment, what is needed is not always at hand. Then you have to go to the nearest store in search of good drills for metal, wood, etc.
Just as a warning for the future - it is not recommended to purchase ready-made whole sets of drills. Yes, they look beautiful and bewitching, but there is no guarantee that all of them will be needed. Except in rare cases, such a variety is not needed in everyday life, a few really necessary units are enough.
Before heading to the store for drills (or one), it is worth considering some points:
- The type of material with which you will have to work, not forgetting about its features and steel grade.
- To what depth should the drill be immersed, that is, whether it will be a through or penetrating procedure.
- Required hole diameter.
- What kind of tool will be used for drilling (manual or electric drill, puncher, screwdriver).
- The parameters of the tool used (speed, power, etc.).
However, this general recommendations. And since the drill is selected for specific purposes, and the product range is diverse, it is worth dwelling in more detail on some important points. At the same time, along the way, we will find out what nuances can be.
Drill classification
Most manufacturers produce their products for metal in a fairly wide range of working sizes. And so that ordinary consumers do not have confusion among such a great variety, regulatory documents (GOSTs) were specially developed. Among them are GOST 886-77, GOST 10902-77, GOST 4010-77. According to them, all products are divided according to several parameters: form, purpose, performance.
But initially, all drills can be divided into two main groups: 1 - for metal; 2 - on wood and others soft materials. Drills for metal have two longitudinal grooves, with the help of which the chips are removed to the side. In addition, they are distinguished by a special sharpening angle. As for core and cone drills, they drop out of this list.
If there is a need to make a hole in the metal layer for a self-tapping screw, you should not take a drill of the same size. Usually, if the thickness of the metal is less than 0.5 mm, then there is no need for pre-drilling, otherwise it cannot be dispensed with. The table below may come in handy.
And since in the assortment of self-tapping screws you can find a large number of pointed black hardware, you should use another table. In addition, their diameter starts at 3.5 mm.
As you can see, the diameter of the drill must be selected to a smaller value than the same parameter of the self-tapping screw.
Dimensions
According to the same GOST 10902-77, there are three groups of drills depending on their diameter and length:
- Short series - the length is in the range from 20 to 131 mm, and the diameter is 0.3-20 mm.
- Extended series - longer drills: from 131 to 205 mm with the same diameter as in the group above.
- Long series - these products are even longer: 205-254 mm, the diameter here is also slightly different and ranges from 1 to 20 mm.
This division makes it much easier for buyers to choose one or another product. For the most part, this refers to the spiral, but there may be other varieties, depending on the needs of production. And as you can see, the classification does not end there. But in everyday life, different situations can also arise, and then you should pay attention to the shape of the drills.
cone products
What are the best drill bits for metal? This we will find out in the course of the text. Cone drills allow you to make holes of arbitrary shape, which can be understood by their name. The master only needs to determine the size of the required circle and accurately set the center of drilling. When working with conical products with even walls, it is necessary to constantly monitor the entire process.
These products make it easy to work with aluminum sheets, non-ferrous metals, also with steel structures up to 6 mm thick. But besides this, they can also be successfully used in relation to other materials: plastic, wood, plywood.
Step drills
It is easier to work with step drills - a certain step corresponds to the required diameter. In such drills, the working part is made in the form of a stepped cone. But unlike the aforementioned tools, there are stepped ring transitions on the surface.
The question of which metal drills are better worries any business master. And the answer may have already been found - due to its shape, processing can be performed at high speed. And it is worth noting that the stepped edges have a high degree of strength. Like many other metal drills, they can be used to work with drywall, plastic, concrete.
Crown shape
The crown shape of the products is used for large sizes, and they can also work with multi-layer materials. And due to their structure, such drills do not depend on the power of the tool used. The cutting force is small, which allows you to work conventional drill. If you need a choice, you should pay attention to the shank - it is desirable that it be powerful and durable.
Thanks to this, the possibility of slipping good metal drills in the chuck is eliminated. It should be taken into account that vibrations and overheating contribute to increased wear of the product. Therefore, it is worth minimizing these factors, and it is better to get rid of them altogether.
Spiral
These are the most common drills today, but by the way, they have always been popular and are unlikely to lose their relevance in the near future. What about domestic use, then it is usually in them that the need arises. Even every schoolchild from labor lessons knows how they are arranged - a cylindrical rod in which there are two grooves with cutting edges. In this case, they are located in relation to the axis of the cutting product at an angle of 10° to 45°.
At the same time, almost everyone has a right cut, but there are drills with left rotation for metal. They are used when it is necessary to drill out some broken fastener when there is no way to manually unscrew it. Actually, this is their main and, perhaps, the only purpose of left-handed products.
Marking
As you might guess, any drill will plunge into the surface or workpiece in the case when its cutting part is harder in relation to the material. Therefore, marking them helps to make the right choice in relation to one or another drill for metal.
As a rule, it is located on the tool shank. And here it is worth paying attention to how it is applied - if all the characters are clearly visible, then the engraving was done in the factory. This is a sure sign to recognize a fake. Depending on the working diameter, the marking of drills for metal (elongated, short, long) may contain various data:
- On miniature drills with a diameter of less than 2 mm, no information is available at all. Which is quite understandable, it will be impossible to consider anything.
- On products with a slightly larger diameter (from 2 to 3 mm), there is already a marking - steel grade, cross-sectional size.
- A tool with a diameter of 3 mm or more contains more data - working diameter, steel grade, manufacturer's imprint.
Drills from foreign companies contain even more useful information:
- manufacturer's name;
- trade index of the company;
- brand of alloy used;
- working diameter of the product;
- accuracy class.
In addition, from the marking you can get some information about what kind of materials you can work with.
Alphanumeric designation
In the marking of any drill for metal (elongated or short), there are not only numbers, but also letters. As a result, you can get information regarding the category of the alloy used for the production of drills, as well as the presence of additional chemical elements in its composition. This allows you to significantly improve their performance.
The letter "P" indicates that strong high-speed tool steel is used for the manufacture of products. Often, a number of elements are additionally added - molybdenum, which is indicated by the letter "M", and cobalt (the letter "K"). Examples of such designations are below:
- P9 - a high degree of wear resistance and ductility, but thermal tolerance leaves much to be desired.
- P18 - this can be considered a good indicator, indicating high grindability in relation to a wide range of hardening temperatures.
- R6M5 is very good drills for metal, which contain molybdenum. And despite decarburization (decrease in carbon concentration), they serve for quite a long time.
- R12F3 - contains 3% vanadium, the grinding parameters are rather low. These drills are designed for medium load.
- R6M5F3 - long service life, but such drills are also recommended for working with steels in medium mode.
- R6M5K5, R9K5, R18K5F2 - the content of cobalt allows you to give products good hardness and heat resistance. They can already be used in high-load conditions.
In addition, on the drills you can find another type of marking: HSS or Din, which already applies to imported products. If necessary, choose really quality tool for specific conditions, all these parameters should not be ignored.
Drills of a number of foreign manufacturers have their own marking - HSS or Din. At the same time, a set of drills for metal HSS-G and HSS-R will be useful in working with cast, carbon and alloy steel with a strength parameter equal to 900 N/mm. Also, such products can be used for processing gray and malleable cast iron, graphite alloys, bronze, brass, aluminum, etc.
If you need to work with more strong metals(up to 1100 N / mm), then HSS-G Co 5 products should be used for work. The HSS-TiAIN and HSS-TiN series are similar to the previous type, but there is corrosion protection.
Choice by color
All drills that are sold in many stores can be divided into 4 main groups depending on the color. Moreover, each shade indicates the presence of certain characteristics. The color scheme is as follows:
- Black - drills have been steam treated after production high temperature. Although they have a rather low cost, they have sufficient strength and reliability.
- Gray - no surface treatment of the products was carried out. As a result, drills are not of high quality and burn out quickly.
- Light Gold - These drills are made from hardened steel and have been treated to improve performance.
- Golden - these are the most durable products, in the production of which titanium is used. Moreover, among all other analogues, they are not only the most reliable, but also durable. But again, due to the nature of production, including the passage of additional processing in several stages, such products, respectively, have the highest cost.
As for the choice of good metal drills, this issue should be approached from the side of practicality. Cheap black drills are suitable for single use and most household needs.
Products of the golden scale should be purchased only if it is justified by rationality - a large front of work, in which several hundred holes must be made in metal surface or blanks.
The best choice
When choosing drills for your own needs, you need to pay attention not only to a number of characteristics, you should also consider which manufacturer they were made by. There are not so many of them, besides, most people, especially home craftsmen, are well aware of their names. The list below includes companies you can trust:
- Metabo.
- Ruko.
- Bosch.
- haisser.
- Polmart.
- Dewalt.
With regard to Metabo and Bosch metal drills, one thing is certain: they will last much longer than their competitors represented by Matrix, Stayer and other Chinese counterparts.
Drills manufactured under the Ruko brand have cross-ground and different type spraying. At the same time, the ratio between quality and cost is at an optimal level.
The Bosch brand itself is already a symbol of high quality and reliability. Each consumer who needs equipment for construction and repair should give preference to this manufacturer. And in the first place.
Products manufactured by Haisser are capable of operating under extreme load conditions. And all thanks to the design features, as well as the use of special alloys in their manufacture.
The company under the name Polmart also produces quality drills that can be used equally with both hand tools and stationary equipment.
Cobalt is present in Dewalt metal drills, which gives them a special hardness. And this is a guarantee that with their help you can drill more than a dozen holes. The sharpening of the products is done in such a way that the contact patch is very small. This avoids those cases when the drill leads to the side by initial stage drilling.
domestic products
Oddly enough, but it is the products of domestic production that can most often be found in many hardware stores. And here the choice is simplified by the fact that you can buy drills without much thought - you will not have to doubt the quality and reliability of the goods.
The Enkor company, which began its activity in 1992, deserves special mention. Today it is the largest production and trading company, whose activities are aimed at the production of various tools, including equipment for it.
As for the Enkor metal drills, the manufacturer presents two main series:
- HSS drills.
- Drill R6M5.
The first group includes products of a cheap price category that perfectly cope with many household needs. Just right for many home craftsmen who love to spend their working time in the country or in their garage. Behind affordable price you can purchase drills with a diameter of 0.8-1 to 13 mm. At the same time, all products are completely ground, and the sharpening angle is 118 °.
The second group is already designed for professionals in their field or more demanding consumers. For the manufacture of such equipment, a more durable material is used - high-speed high-speed steel R6M5. The surface of the products is also completely ground, and the sharpening angle is already 135 °. And thanks to the cross-shaped undercut of the jumper, preliminary punching of the metal surface or the workpiece is not required.
A set of drills for metal "Zubr" is also worthy of attention. This equipment has such necessary parameters as quality, reliability, cost, which are also harmoniously combined with each other.
- it is important to know not only professional builders, but also those who often do metal work with their own hands.
Today in any hardware store you can buy drills of various shapes and sizes, and it is important to choose among all this variety of equipment exactly what you really need.
In the article you will find out which drills are better to choose in this or that case, whether it is worth buying sets and which ones, or only one device, as well as other questions that will help you make your choice right drill for metal.
Before buying a drill, be sure to decide for what purposes you will use it, otherwise choose correct option will be practically impossible.
You should choose a drill based on the type of drill that you will use in your work, as well as the type of holes that you need to make.
For holes with a large section, drills are used that have the appropriate length and diameter - usually this powerful drills with low turnover.
The color of the drill is an important criterion to help you choose the right one. correct device. By color, you can easily determine the quality of the product and, therefore, the expected service life.
Better not to buy gray color, because they are the least reliable of all.
The gray color indicates that the drill has not been processed in any way: such tools do not have a protective layer, resistance to fire and deformation.
Naturally, it will be the cheapest to buy such a drill, however, it will not work to use it more than once.
The black drill bit for metal is of higher quality because it has been processed with superheated steam.
The service life of such products will be higher, as well as the cost, but the price for them is low, so buying such drills will not be a problem.
The best drills are those that have a golden hue, however, they also differ from each other.
Tools with pale gold are somewhat inferior in quality to bright products - they undergo a processing process that allows you to remove the internal stress that exists in the material, and also increases the strength of the product.
The most expensive to buy drills are bright yellow, however, they are the most durable and durable. They are made from titanium - the most durable look metal.
Such drills are characterized by a minimum level of friction, so it is more convenient to work with them, and their service life is much longer compared to other tools.
Of course, it is logical to buy the highest quality device - this way you will save time and will be able to use the tool much longer.
If metal work is not your permanent activity, then it is quite possible to get by with cheaper analogues - drills in black or light golden color.
The most important thing when buying a drill is its size.
It is not difficult to buy a drill of the size you need, because. the size grid of this tool is very wide - the main thing is to know what size you need.
If you are not sure which size to choose, then it is best to be guided by the GOST classification, which divides all devices into 3 groups.
The first group includes short instruments, the size of which does not exceed 20 mm in diameter and 131 mm in length.
The elongated group includes tools that reach a length of up to 205 mm, while their cross-sectional parameters are similar to short drills.
Long group drills include tools with a diameter of 1-20 mm and a length of 56-242 mm.
Drill shape
The drill is a simple tool and consists of only three elements: the cutting part, the shank and working surface, which is necessary so that the chips do not accumulate inside the hole, but are immediately brought out.
Although it is a standard tool for metalworking, many people also use it to work with wood, plexiglass, ceramics, plastics, concrete and other materials.
Thus, you can choose its shape, suitable not only for working on metal, but also for other surfaces.
According to their design, drills are divided into two groups: the tools of the first group are called flat, and the second - spiral.
Decide which of the two types suits you best before you buy a drill.
The advantages of flat tools are that they do not react to possible distortions during operation, they are cheaper than spiral ones and have a simpler design.
The disadvantages of such drills are the smaller diameter when sharpening and the lack of automatic chip removal.
One of the varieties of such drills is a cone tool for metal. Such a drill can be purchased separately, or in a set, depending on the need.
The cone type tool is used to work with drilling machine, or a two-handed drill. If you need to make a hole with a large cross section, then pay attention to this option.
The more popular type of drills are twist drills. They are more often bought due to the large application possibilities - they are suitable for creating almost any holes and working with different materials.
Such a drill has the shape of a cylinder, and on its “body” there are special recesses-grooves in the amount of one or two pieces.
Due to their presence, the chips do not linger during operation, but are immediately removed from the hole.
Spiral devices differ in the type of tail: it can be standard, crown, designed for threading, left-handed, high-precision or stepped.
The standard cylindrical device has a diameter of up to 12 mm and can be used both in production and at home.
Private craftsmen most often buy this type of tool. A core drill is used to create large holes with a diameter of at least 30 mm.
At the tip of the tool there is a crown equipped with teeth. Such a device is best used for working on thin metal.
The thread tool allows you to create a thread of the required section. If you purchase a tool for these purposes, then you need to buy one that will be 1 mm smaller than the cross section of the future hole.
The stepped device is the most versatile, because it allows you to make holes of different diameters.
The only limitation on working with it is that it can only be used to work with sheet metal no more than 2 mm thick.
The diameter of the tool is quite large and can reach 30 mm.
Buying such a drill is usually more expensive than the rest, but the price depends on the size of the section, and for small sections it will be quite acceptable.
The left-hand device can only be used to unscrew the hardware: screw, bolt or self-tapping screw, so buying it will only be relevant for these purposes.
Tools that have increased accuracy are the best of all possible. They are purchased in cases where the result should be as high as possible.
The price of such devices depends on the accuracy class to which they belong - it can be class A1 or B1.
Manufacturer and marking
Before you buy a drill, look at where and by whom it was made.
It is better to buy only proven devices, because. if the production technology was violated, then neither color nor correct form products will not help create a quality result.
From right technology production depends on how well the tool will be sharpened, how strong it is and how it can last, resistance to corrosion and other external influences, etc.
It is best to look in advance on the Internet for reviews of a particular company and buy a drill for which the largest number positive feedback.
The highest quality metal drills are marked with the USSR.
Finding them today is not so easy, however, if you buy such a tool, it will last a long time: many note the high quality, long term operation and minimum abrasion of the device.
Ruko tools are also well-deservedly popular: they are of high quality and reasonable price.
The most popular models are TL 3000, due to the fact that they have a wide range of functions, as well as cross sharpening and several layers of deposition of titanium modifications.
Such drills are not always used for metal work - they are most effective in processing materials that form large chips, such as wood.
Before choosing a device marking, please note that the diameter may vary depending on the manufacturer.
If you see a drill without marking, then its cross section is less than 2 mm, on devices with a diameter of 2-3 mm indicate the steel grade and section, and on drills larger diameter you can also find information about the cross section, grade of the material and the presence of additional substances in it, if any.
The marking of the tool includes a combination of letters and numbers.
It is better to remember them before you buy a tool: the letter P denotes high-speed steel, the alphanumeric combination indicates the presence of additional impurities in the material: it can be, for example, K6 - this is how cobalt is designated, but there may be other impurities.
If you decide to buy tools Russian production, then there will be no other markings on them, but if they are foreign tools, then they should also be indicated: country of origin, trademark, material grade, cross section and diameter of the tool, advice on use and accuracy class.
Foreign instruments have specific markings, usually these are combinations of letters like HSS-R, HSS-G, etc.
Drill many different holes in the most hard materials, do not become dull and not break, a high-quality drill for metal is capable. High performance from the drill can be expected if it is correctly selected for the product being drilled, made of quality material and sharpened as needed.
Let us consider in detail the types of drills for metal, their characteristics, features of use and criteria for choosing a cutting tool.
A drill for metal is an indispensable tool for a modern builder
The metal drill is used for cutting holes in alloyed and non-alloyed steel, its alloys, in non-ferrous metal, cast iron and other types of metal. Often these drills are used when working with hard plastic materials. The scope of metal drills is unlimited: the tool is used in a variety of fields of activity and in everyday life.
It is difficult for an ordinary buyer to navigate among a wide range of drills that are presented today on the construction market. Without competent advice from a specialist, choosing the right model is quite difficult.
Structurally, a metal drill has a working part (cutting and calibrating part) and a shank.
Drills for metal belong to the category of spiral, as they have spiral grooves along the entire length for chip removal
The place at the end of the drill is the cutting part, where sharpened edges are placed, ensuring the penetration of the drill into the material. Behind the cutting part is a calibrating part, equipped with grooves for removing metal chips. The calibrating part is responsible for the smoothness of the edges of the hole and sets the desired diameter.
The material of manufacture and the structure of the working part determine the purpose of the cutting tool.
Drill attachment to hand tool or machine tool through a shank, which can be tapered, cylindrical or hexagonal.
Classification of drills for metal
Depending on the design features, drills for metal can be divided into the following types:
Features of marking drills for metal
When choosing a drill for metal, you need to pay attention to its marking, which may indicate the diameter, steel grade, accuracy class and manufacturer.
Drills with a diameter of up to 2 mm are not marked, on products up to 3 mm the diameter and steel grade are indicated, and on larger drills more extensive information may be indicated.
Basic designations:
- markings starting with a letter R indicates products made of high-speed steel;
- numerical values determine the content of a particular substance in the alloy, for example: K6- six parts of cobalt (increases the heat resistance of products); M4- content of molybdenum;
- for comparison, drill with marking Р6М5К5 much stronger than marked drills R6M 5, by adding cobalt (the price of reinforced cobalt drills is higher than ordinary ones);
- imported analogues have designations HSS or Din; the HSS drill for metal usually has an additional marking of Latin letters indicating the working material ( HSS-G drill alloyed and carbon steels, aluminum and copper alloy, cast iron; HSS-E in addition to the listed materials, they will cope with acid-resistant and stainless steel; HSS-G Tin- extra strong, suitable for drilling titanium alloy).
For the manufacture of drills for metal, GOST regulates the use of high-speed tool steel grade P18
What can tell the color of the drill
The method of finishing the drill will win back important role in ensuring the strength and reliability of the tool. The color of the drill indicates what materials were used in the processing of the product.
Grey colour indicates that the drill was not amenable to any processing. This is the cheapest and least stable product that will not cope with all types of metal and will not last long.
Black color the drill acquires after processing with superheated steam - this increases the service life of the product.
Dull golden hue- a sign of the use of vacation to relieve internal stress in the hot metal. This procedure reduces the brittleness of the hardened drill, giving the material strength.
Intense golden color have drills coated with titanium nitrite - this provides the highest wear resistance. In operation, such drills are the most convenient (friction is reduced) and durable, the only drawback is their high cost.
Competent sharpening of the drill: the need for the process and the algorithm of actions
A high-quality drill is designed for long-term use, however, it can become dull over time. Of course, you can replace it with a new one, or you can avoid unnecessary costs and sharpen the drill yourself.
In everyday life, for household needs, drills with a diameter of up to 16 mm are usually used, which can be sharpened on a regular grinding wheel without resorting to " high technology". In the absence of a “grindstone”, you can use a grinder or an electric drill, which must be fixed before work.
Before you start sharpening a drill for metal, you need to prepare:
- eyes should be protected with goggles, hands with gloves;
- prepare a small container for coolant (engine oil, water) - if the drill is not periodically cooled, the metal will overheat and will not be able to withstand high drilling loads in the future.
The sequence of actions when sharpening the drill is as follows:
- Pressing the drill firmly against the grinding wheel, we process the back surface of the tool. The sharpening angle must not change.
- After finishing the processing of the back surface, a regular cone should form (it can be seen by looking at the tip of the drill from the side).
- Holding the sharpening angle, the working part of the drill is processed.
- Finishing of the back of the tool occurs after processing the working part of the drill.
- The size of the jumper at the tip of the drill should not be more than 0.4 mm (with a drill diameter of up to 8 mm) and no more than 1-1.5 mm for larger drills.
You should not focus only on the tip, the entire working side surface drill
When sharpening for the first time, it is advisable to practice on old, failed drills in order to feel how to hold and press the tool correctly. If you insert the "trial exhibit" into a drill and drill a couple of holes, it will immediately become clear where the mistake was made during processing.
When choosing drills for working with metal, you should adhere to the following recommendations:
At right choice tools and good sharpening, metal drills can be used for a long time and without problems, both for their intended purpose and for drilling holes in other materials: wood, plastic, plexiglass and stone.
Metal drill markings are special designations that are indicated on the cutting tool. It is imperative to pay attention to all the indicated numbers and letters in the marking, as they indicate the diameter of the device, the steel grade from which it is made, the accuracy class, as well as the country of origin or the brand of manufacture. Drills with a diameter of less than 2 mm are not marked, products with a size of 2 to 3 mm have diameter and steel grade designations. If the cutting tool is large (more than 3 mm), then all possible parameters are indicated on it. You need to know the marking features in order to choose drills of the required size, since not all devices are suitable for drilling certain holes.
Twist drill marking: the meaning of the letters
Solid spiral cutting tools, made of high-speed steel, have the following grades: R 9, R18, R9K15. The letter P means that the product is made of high speed steel. After the letter P, a number is indicated that indicates the amount of tungsten that the tool contains. An average is taken. More letters and numbers follow. The numbers that are indicated after the letter indicate the content of the alloying substance in the alloy, this is a percentage parameter indicating the mass fraction of substances. For example, if K6 is indicated, this indicates that the alloy contains six parts of cobalt, which contributes to an increase in heat resistance. If M4, then there are four parts of molybdenum. That is, after the letter P and the number, a special letter (name of the element) and a number (the amount of the element present in the alloy) are indicated - this is the percentage content of the alloying element.
photo: marking twist drill for metal
For example, the following marking R6M5F3 is indicated. This means that the drill is made of high speed steel with the addition of 6 parts of tungsten, 5 parts of molybdenum and 3 parts of vanadium.
Important: the marking does not indicate the quantitative addition of chromium, as well as carbon, since the first element has a stable parameter of 0.4%, and the second has a value equal to the content of vanadium.
An example of a symbol for a spiral tool with cylindrical shank.
A device that has increased accuracy, diameter - 15 mm, version 1, accuracy class A, designated: 2300-7066 A1 GOST 886-77. This value indicates the accuracy class of the instrument. It can be A1 - increased accuracy or B1 - normal accuracy. 2300 - operational and design characteristics, 7066 - serial number of manufacture. GOST - in accordance with what standards the device is manufactured.
If you purchase an elongated spiral drill with a cylindrical shank, then AB 2300-0055 will be written on it. AB is the index of the enterprise, 2300 is the operational and design characteristic, 0055 is the serial number of the device standard size according to the factory standard.
Installation with a tapered shank has an indicator of - 2301, for integral ones, it is necessary to indicate trademark manufacturer, diameter, grade of hard alloy, the letter "T", if the installation has increased accuracy.
Imported devices are designated HSS or DIN. The HSS device has an additional marking - a letter that indicates the working material. For example:
- HSS-Co (addition of cobalt);
- HSS-E (cobalt addition);
- HSS-G (metal addition P4M3 - molybdenum);
- HSS-R (metal addition P2M1 - molybdenum).
DIN drill marking has standard parameter 338 is a technical standard that fully complies with GOST 10902-77.
Designation of a center drill
The designation of centering drills is set in accordance with GOST 14952-75. They have an additional letter A, B, C or R in the designation.
- A and B indicate that the design is used for holes of 60 degrees and has (B) or does not have a safety cone (A).
- C - used for holes of 75 degrees without a safety cone.
- R - for holes that have an arcuate shape.
photo: marking a center drill for metal
Installations have a designation, for example, such 2317-0118 GOST 14952-75. 2317 is an operational and design characteristic, 0118 is the serial number of the device standard size according to the factory standard.
For example, if the number 0001 is indicated, then the diameter is 1 mm. Group B devices have marking features. 2317-00-12 if it's the second version, and 2317-0113 if it's the first.
Group C is designated: 2317-0022 (second version), 2317-0124 (first version), group R 2317-0027. This is if the diameter is 1 mm.
The marking of the p6m5 drill in this type of device may not be indicated.
Marking of the first cutting tool
Strength is indicated:
- P18 - a satisfactory indicator, increased grindability, indicates a wide range of hardening temperatures.
- R 9 - are distinguished by increased wear resistance, a narrower range of hardening temperature indicators, increased ductility.
- Р6М5 - molybdenum is additionally added, increased tendency to decarburization.
- R12F3 - have reduced grindability, are used for drilling in medium mode. Added 3% vanadium.
- R6M5F3 - increased wear resistance, work on average speed cutting, are used for carbon and alloyed tool steels.
- Р9К5, Р6М5К5, Р18К5Ф2 - cobalt is added, which provides an increase in secondary hardness, heat resistance, and an increased cutting mode.
They have the designation 2304 - operational and design characteristics. Full marking 2304-4001-50-108. The indicator from 50 to 108 may vary. It indicates the possible value of the diameter.
Conclusion
Each device must indicate the steel grade (P and number), additional elements included in the composition (M, K, F and the figure - percentage), the diameter of the drilling part, as well as the trademark of the manufacturer. In order to choose the device of the correct size, pay attention to these parameters, as well as to symbol designs.
