Almost every head of the family has a minimum supply of necessary tools for various purposes. And one of the most common jobs is drilling. And someone has 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 they will all be needed. With the exception of rare cases, such a variety is not necessary in everyday life, just a few really necessary units are enough.
General recommendations for choosing drills
Before you go to the store for drills (or one), it is worth considering some points:
- The type of material that you have to work with, not forgetting about its features and steel grade.
- At what depth should the drill be immersed, that is, will it be a through or penetrating procedure.
- The required hole diameter.
- What kind of tool will be drilled (hand or electric drill, hammer drill, screwdriver).
- Parameters of the used tool (speed, power and others).
However, these are general recommendations. And since the drill is selected for specific purposes, and the product range is diverse, it is worthwhile to dwell on some important points in more detail. At the same time, we will find out what nuances might be.
Drill classification
Most manufacturers produce their metal products 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) have been 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, execution.
But initially, all drills can be divided into two main groups: 1 - for metal; 2 - for wood and other soft materials. Drills for metal have two longitudinal grooves with which the chips are diverted to the side. In addition, they are distinguished by a special sharpening angle. As for core and cone drills, they fall out of this list.
If there is a need to make a hole in the metal layer for a self-tapping screw, do not take a drill of the same size. Usually, if the thickness of the metal is less than 0.5 mm, then preliminary drilling is not necessary, otherwise you can not do without it. The table below may come in handy.
Metal thickness mm | 0.7 | 1,0 | 1,5 | 2.0 | 3.0 | 4.0 |
Drill diameter mm | 3.3 | 3.4 | 3,5 | 3.6 | 3,7 | 3.8 |
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 begins with 3.5 mm.
Metal thickness mm | 1,0 | 1,5 | 2.0 | 3.0 | 4.0 |
Drill diameter mm | 2,5 | 2.7 | 2.9 | 3.0 | 3,1 |
As you can see, the diameter of the drill must be selected a smaller value than the same parameter of the 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 ranges from 20 to 131 mm, and the diameter is 0.3-20 mm.
- An 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 separation makes it much easier for customers to choose a product. For the most part this applies to the spiral form of drills, but there may be other varieties depending on the needs of production. And as you can understand, 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
Which metal drill bits are better? 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 circumference and precisely set the drilling center. When working with conical products with smooth walls, it is necessary to constantly monitor the entire process.
With the help of such products it is easy to work with aluminum sheets, non-ferrous metals, and 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. For 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 drill bits for metal is better is of concern to any housekeeper. And the answer may have already been found - due to its shape, processing can be performed with high speed. And it is worth noting - 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 castellated shape of the products is used to drill large holes , and they can also work with multilayer materials. And due to its structure, such drills do not depend on the power of the tool used. The cutting force is small, which allows you to work with a conventional drill. If you need a choice, you should pay attention to the shank - it is desirable that it is powerful and durable.
Due to this, the probability of slipping good drills for metal in the chuck is eliminated. It should be noted that vibration and overheating contribute to increased wear of the product. Therefore, it is worth minimizing these factors, but it is better to completely get rid of them.
Spiral
These are the most common drills to date, but by the way, they have always been popular and are unlikely to lose their relevance in the near future. As for domestic use, it is usually in them that the need arises. Every student knows how they work from the lessons of labor ā a cylindrical rod in which there are two grooves with cutting edges. Moreover, they are located along the axis of the cutting product at an angle from 10 Ā° to 45 Ā°.
At the same time, almost all spiral drills have a right cut, but there are drills with left rotation on metal. They are used if necessary to drill out any 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 sink into the surface or the workpiece in the case when its cutting part is harder with respect to the material. Therefore, to make the right choice regarding this or that drill for metal, their marking helps.
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 is done in the factory. This is a sure sign to recognize a fake. Depending on the working diameter, the marking of drill bits for metal (elongated, short, long) may contain various data:
- On miniature drills with a diameter of less than 2 mm, there is no information at all. Which is understandable, it will be impossible to consider anything.
- On products with a slightly larger diameter (from 2 to 3 mm), marking is already there - steel grade, cross-sectional size.
- An instrument with a diameter of 3 mm or more contains more data ā the working diameter, the grade of the steel of manufacture, the impression of the manufacturer.
Drills from foreign companies contain even more useful information:
- name of the manufacturer;
- company trademark;
- grade of alloy used;
- working diameter of the product;
- accuracy class.
In addition, a little information can be gleaned from the marking regarding what 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 āPā indicates that durable 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 below:
- P9 is a high degree of wear resistance and ductility, but thermal tolerance is poor.
- P18 - this can be considered a good indicator indicating high grindability with respect to a wide range of quenching temperature.
- P6M5 is a very good drill for metal, which contain molybdenum. And despite decarburization (a decrease in carbon concentration), they serve for quite some time.
- P12F3 - contains 3% vanadium, the grindability is rather low. These drills are designed for medium load.
- R6M5F3 - long service life, but also such drills are recommended for work with steels in the average mode.
- R6M5K5, R9K5, R18K5F2 - the cobalt content allows to give products good hardness and heat resistance. They can already be used in high load conditions.
In addition, on drills you can see a different type of marking: HSS or Din, which already applies to imported products. If you need to choose a really high-quality tool for specific conditions, you should not ignore all these parameters.
Drills of a number of foreign manufacturers have their own marking - HSS or Din. In this case, a set of drill bits for metal HSS-G and HSS-R will be useful in working with cast, carbon and alloy steel with a strength parameter of up to 900 N / mm. Also, such products can be used for processing gray and malleable cast iron, alloys of graphite, bronze, brass, aluminum, etc.
If it is necessary to work with stronger 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 corrosion protection is present.
Color selection
All drills that are sold in many stores can be divided into 4 main groups, depending on the color. In addition, each shade indicates the presence of certain characteristics. The color scheme is as follows:
- Black - drills after production have been treated with high temperature steam. Although they have a fairly low cost, they have sufficient strength and reliability.
- Gray - no surface treatment of the products was carried out. As a result of this, the drills are not of high quality and quickly burn out.
- Light gold - these drills are made of hardened steel and have undergone appropriate processing in order to increase operating parameters.
- Gold is 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 characteristics of production, including the passage of additional processing in several stages, such products, respectively, have the highest cost.
As for the choice of good drills for metal, then this issue should be approached from the practicality side. Cheap drills of a black shade are suitable for single use and the majority of household needs.
Golden gamut products should be purchased only if rational justified - a large front of work, in which it is necessary to make several hundred holes in a metal surface or workpieces.
The best choice
Choosing drills for your own needs, you need to pay attention not only to a number of characteristics, you should also consider what kind of manufacturer they were made. There are not many of them, in addition, most people, especially home masters, know their names very well. The list below includes companies you can trust:
- Metabo.
- Ruko.
- Bosch
- Haisser.
- Polmart
- Dewalt.
Regarding metal drills Metabo and Bosch, one thing is certain: they will last much longer than their competitors in the person of Matrix, Stayer and other Chinese counterparts.
Drills manufactured under the brand name Ruko have cross sharpening and various types of spraying. Moreover, the ratio between quality and cost is at an optimal level.
The Bosch brand itself is already a symbol of high quality and reliability. Every consumer who needs a tooling for construction and repair should give preference to this manufacturer. And first of all.
Haisser products are designed to withstand extreme loads. And all thanks to the design features, as well as the use of special alloys in their manufacture.
A company called Polmart also produces high-quality drills that can equally be used when working with both hand tools and stationary equipment.
Dewalt metal drills contain cobalt, which gives them 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 made in such a way that the contact spot is very small. This avoids those cases where the drill leads to the side at the initial stage of drilling.
Domestic products
Oddly enough, but it is precisely the products of domestic production that can most often be found in many construction stores. And here the choice is simplified by the fact that you can buy drills without much thought - there is no doubt in the quality and reliability of the goods.
Special mention is worthy of the company "Enkor", which began its activities in 1992. Today it is the largest manufacturing and trading company, whose activities are aimed at the production of various tools, including equipment for it.
As for the drill bits for Enkor metal, the manufacturer presents two main series:
The first group includes products of a cheap price category, which perfectly cope with many domestic needs. Just for many home masters who like to spend working time in the country or in their garage. For an affordable price, you can purchase drills with a diameter of 0.8-1 to 13 mm. In this case, all products are completely polished, and the sharpening angle is 118 Ā°.
The second group is designed for professionals or more demanding consumers. To manufacture such equipment, a more durable material is used - high-performance high-speed steel P6M5. The surface of the products is also completely polished, and the sharpening angle is already 135 Ā°. And thanks to the crosswise undercut of the lintel, preliminary coring of the metal surface or workpiece is not required.
A set of drills for metal "Bison" is also worthy of attention. At this equipment such necessary parameters as quality, reliability, cost, are also harmoniously combined with each other.