A metal drill is the number one cutting device, and the market is oversaturated with models with different sets of characteristics. Therefore, the question that often arises, which drills for metal are better, does not have a clear solution. To select a tool, you need to have sufficient experience or an idea of its characteristics. Let's focus on what features drills have in different designs, how to distinguish good options from low-quality ones, and what parameters to choose a tool based on.
The drill is a must-have tool in the home workshop Source convera.ru
Types of drills
The ideal drilling result depends not only on the professionalism and experience of the master, but also on the correct selection of the drill. The right tool will make the job much easier. Types of drills for metal surfaces differ in the type of configuration and the material from which they are made.
1. Twist drills are standard cylindrical products. They reach 80 mm in diameter. Made from high quality steel. Their design is such that the working surfaces are sharpened at an angle of 118 degrees. They are needed for almost all basic drilling work in metal. This is a versatile, durable tool.
2. Conical (or stepped) drills - are made in the form of cones with a stepped surface (spiral). They can easily drill a two-millimeter hole. They are also used to correct small defective holes that were formed as a result of poor performance of another tool.
3. Core drills are serrated hollow bits. They are also called annular cutters. The craftsman needs them to work with thin metal to make neat holes up to 30 mm. This tool can drill to great depths, due to the fact that the chips pass into the cavity of the crown.
4. Feather (flat) drills consist of replaceable working plates. They are designed to drill perfect deep holes in metal of any strength. The peculiarity of this type is that the flat drill practically does not distort during drilling. In addition, they are the cheapest, so they attract the attention of craftsmen.
Depending on the production material, drills are divided into cobalt and carbide. The first ones are made of cobalt. The second ones are made of high-strength alloys. — Cobalt drills are used at high temperatures, as they do not lose their qualities. Cobalt alloyed high speed steel tools allow you to work with very tough materials and highly tough metal products. Cobalt drills have an average price, but their quality and performance fully justify it. — Carbide drills have high cutting edge hardness. The equipment itself is usually made of simple steel for metalworking tools. And the plates are made of carbide alloy. Such models are needed for drilling products made of particularly strong materials of great thickness. The peculiarity of a carbide drill is that it can self-sharpen during operation.
Standard diameters of drills for metal - Machine tools, welding, metalworking
Drilling metal products is an operation very familiar to home craftsmen. However, this process is simple at first glance. For successful work, you need to understand which drills are best to use and how to choose quality products.
How to choose a drill for metal so that it does not become dull or break? Lots of questions to consider before purchasing. Next, we will analyze the types of metal drills, their classification, markings, designations, and also provide photos of each type of metal drills.
Explanation of markings
Before you figure out what types of drills there are by model, you should pay attention to the markings. The designation is primarily influenced by the diameter. For thin products, marking is usually not provided; products starting from 3 mm are marked. As the thickness increases, the amount of information increases - accuracy classes, manufacturers, etc.
The alphanumeric designation is simply deciphered. By tradition, domestic products begin to be designated with the letter P, that is, high-speed steel. The next number indicates the percentage of tungsten.
The following numbers and letters contain additional components and their quantities. So, K is cobalt, M is molybdenum.
The greater the number of elements included, the better the characteristics (temperature, mechanical load) of the drill.
carbon and chromium are not applied, because with the first the content is proportional to the amount of vanadium, and the second is always 4 percent. When the introduction of vanadium is more than 3%, the letter F and its amount appear.
Imported products are marked as DIN and HSS.
DIN designates multi-purpose tools suitable for normal and deep-hole drilling. They have different coatings, easily recognizable by color.
HSS have differences in the letters following the abbreviation. G - indicates the presence of a tool capable of handling carbon and alloy steel; it will process cast iron, aluminum, and copper alloy. E – a tool that can handle alloy/carbon steels, as well as acid-resistant and stainless metals.
Titanium steels are designated HSS-G TiN and HSS-G TiAlN. For them, any of the above metals will not be a hindrance.
Drills for household use
All types of metal drills can be divided into areas of application. So, we can distinguish between domestic and industrial use. The second direction involves use in specialized equipment - machines. Conventional ones can also be used in machine tools, but they are most widespread in portable power tools.
Spiral cylindrical. A drill for metal, as everyone is used to seeing it. Mainly made of high-speed steel HSS, P6M5. Sometimes you can find the highest quality ones made from P18 steel. Nowadays this steel is practically not used, but if you come across it, then this is a high-quality option.
The marking of metal drills of this type assumes the following modifications: P9, P18, P9K15. The letter P denotes high-speed steel construction.
The numbers determine the percentage of tungsten in the tool. Subsequent letters and numbers determine the presence and quantity of alloying substances.
For example, K6 means that the alloy contains 6 parts cobalt, which contributes to heat resistance. M4 – the presence of 4 parts of molybdenum.
With tapered shank. Most often intended for a drilling machine. The shank is made in the shape of a cone, the so-called Morse Cone, which is crimped into the chuck.
There are drill models that support similar types of tools. In this case, they are simply inserted into the drill without the use of chucks. Similar models of drills are low-speed.
If it is necessary to drill holes of large diameter (from 23 mm), then they are drilled using similar models.
The markings are similar to conventional spiral ones. The alphanumeric designation determines the presence of components and their relationship.
Crown type. The classification of drills for metal also assumes this type. They are designed to create large diameter holes. They are similar to crowns for concrete work, but without carbide elements on the teeth. Manufactured from HSS steel. Has fine teeth. Perfect for creating holes larger than 30 mm in diameter. But it is only suitable for thin metal.
Crown models with a diameter of less than 2 mm are not marked; over 3 mm, the brand and thickness are indicated. For large sizes, information about the manufacturer, steel composition and other characteristics is indicated. All data can be found on the packaging.
Step type (conical). This option was discussed in detail in this article. They became widespread relatively recently. The diameters of the holes can also be significant. However, you can create small ones. The tool has universal characteristics and the ability to drill from 6 to 30 mm.
Centering. They were also discussed in detail in the corresponding article. Necessary for centering the points for creating holes in workpieces before drilling. The table below will help you understand the notation.
Carbide modifications. Used for processing durable metal, including hardened metal. In this case, only this option can help. The tip has a carbide plate - alloy BK8 (win).
Such tools have become widely known for drilling concrete. However, unlike the concrete analogue for metal, it has a sharp one-sided sharpening angle. This provides the ability to effectively process metal.
There is only one problem - they are rarely found on sale.
Left-handed. There is also a modification of drills that is not often found on sale. They are used for drilling broken bolts and screws that cannot be removed with an ordinary model.
With increased accuracy. Used in work with increased precision requirements. The marking of a drill of this type contains the designation A1, B1. These are accuracy class designations.
Cobalt. We discussed this in detail in the article about cobalt drills. Recently they have become widespread and are sold everywhere. They have increased durability and allow processing particularly hard parts.
How do cobalt drills differ from regular ones? Most often by markings. For example, the presence of the inscription P6M5K5 indicates the presence of cobalt in the composition, a reinforced structure. The cost is several times higher than regular ones.
Titanium coated. Easy to identify by its yellow color. This is just the sputtering of titanium nitride. There is often controversy over the strength of cobalt and titanium drills. We can definitely say that cobalt is much stronger. The presence of a titanium coating provides cutting edges with protection more from rust than from abrasion.
Marking features
Markings on drills depend on their technical properties and country of manufacture. Russian GOST requires markings on all drills with a diameter of two centimeters and above. It usually contains basic information about the product: the grade of steel and the diameter of the drill. The marking is located on the shank of the cutting tool. On domestically produced instruments you can see markings of this type: “Р6М5К”. This is a formula in which each symbol is detailed information about the drill. This marking, for example, means that the product is made of high-speed steel (P), the tungsten content in it is six percent (6), molybdenum - five percent (M5) and five percent cobalt (K5). Foreign-made drills bear the HSS marking and additional designations, which, just like those of domestic manufacturers, indicate the characteristics of the product. For example, "HSS-4241" means that this model is suitable for working with aluminum.
Metal drills: varieties of diameters depending on the shape and task
The need to make a hole in a metal product arises not only among builders or metal craftsmen. Quite often, such a need may arise at home. But to make a hole you will need suitable tools and drills of the required diameter.
At the same time, the question arises: what types of metal drills exist? Surely each type has its own advantages and disadvantages. The answers to this and many other questions are in this article.
Selection Criteria
Choosing a drill for metal is a very important step. After all, the quality of work largely depends on this product. By purchasing a low-quality model or a drill of the wrong diameter , you can not only ruin your mood, but also damage the metal product in which you needed to make a hole.
Therefore, when choosing, you should rely on the following characteristics:
- Required diameter.
- Symmetrical sharpening.
- Hardness and strength of the product.
- The type of metal from which the drill is made.
- Manufacturer.
- And, of course, the price.
In order not to make a mistake with the choice, experts recommend purchasing such devices in a set. Usually in one package there are 6-8 drills of different diameters. However, products can be purchased individually. True, this will require certain knowledge.
Variety of shapes and diameters
A standard drill has a cylindrical shape and consists of a cutting part and a shank. At the same time, each product has special recesses (so-called working surfaces) that remove chips from the hole. Based on these parameters, a wide variety of products are distinguished, each of which has its own diameter ranges:
- Screw model with tapered shank . Most often, such modifications can be found on special two-handed drills or drilling machines. In this case, the drill is mounted on a conical shank, and not on a chuck, as usual. Such products are used for drilling large holes, and therefore have a wide diameter.
- Crown varieties . The cutting part of such models is much wider than the shank, so it is shaped like a crown. As a rule, such modifications are used to drill holes in several metal sheets. Therefore, there are frequent teeth on the working surface.
- Products with a stepped shape . They appeared relatively recently, so they have a less wide selection of products. Nevertheless, they are gaining popularity by leaps and bounds due to their versatility. The fact is that with the same drill you can make holes with a width of 4 to 36 mm. Accordingly, the more “steps”, the higher the cost. However, this innovation can only be used on sheet metal.
- Left-hand modifications . It is quite difficult to find this variety in a store due to the specificity of its application. The purpose of such devices is to remove a broken screw or bolt. Based on this, there are only 5–7 varieties in diameter.
- Carbide models . They are distinguished by a one-sided sharpening angle and high strength. These qualities allow the products to be used for working with strong metal. Most often, such drills are produced with a small radius, but you can always make an individual order.
- High precision products . As the name implies, such devices are designed for high-precision work, so the size error is minimized. Because of this, high-precision drills are significantly higher in cost than standard models. As a rule, they are used in special enterprises, and not at home.
- Threaded _ They are used only in cases where it is necessary to make a thread in the hole. However, despite their narrow specialization, they have a huge variety in diameter.
Diameter and marking
The presence and volume of information on the drill depends on the size of the product. That is, the larger the diameter, the more data is indicated. Typically, manufacturers adhere to the following sizes:
- Drills with a cross-section of up to 2 mm are not marked.
- Products with a diameter of 2 to 3 mm contain information about the steel grade and cross-section.
- On models from 3 mm, data on the manufacturer, cross-section and alloy composition are entered.
However, this applies only to domestic producers. Foreign companies try to provide as much information as possible about the product . This especially applies to large brands, which usually indicate:
- The country in which the drill was made.
- Company `s logo.
- Composition (usually the grade of alloy or steel).
- Product size and cross-section.
- Accuracy class.
- And even brief recommendations for use (for which metal a particular drill is best suited).
To decipher the markings you do not need any specific skills. The manufacturer made sure that everything was intuitive. For example, the letter “P” is used to mark high-speed steel, and numbers with letters indicate the proportions of a particular element. For example, the larger the number next to the letter (for example, K - cobalt), the higher the concentration of this element.
In conclusion
In the modern world there are many products designed to work with metal. However, if you need to make a hole in a metal object, then nothing will cope with this task better than a special drill. Nevertheless, it is very important to choose a product of a suitable diameter, since the outcome of the work largely depends on this parameter.
Using low-quality products can harm both the metal object and yourself. Therefore, you should purchase products from well-known brands that not only produce high-quality drills, but also provide a wide variety of models.
- Vitaly Danilovich Orlov
Classification by color
By color you can determine the characteristics of the tool: strength, durability, purpose. Drills are available in three colors: gray, black and gold. Gray drills are among the simplest, cheapest and most short-lived. They do not have a protective coating, so their performance characteristics are quickly lost during operation. They are not suitable for high temperatures or heavy mechanical stress. But they are often used as a one-time use for simple work.
Black drills are treated with high temperature steam during manufacturing. Thanks to this treatment, the material is hardened and becomes durable. They wear out less and last longer than gray ones.
Golden drills can be lighter and more saturated. Light yellow very durable. They are made from high-speed steel using heat treatment technology. Bright gold cutting tools are even more durable than light gold ones. They have a titanium nitride coating. When drilling a hole, the gold drill experiences almost no friction force, which significantly extends its service life.
Visual identification of the drill
Depending on the color of the tool, you can understand the characteristics of the drill. This opportunity appears due to the appearance features:
- Dark shade. It indicates that the cutting tool has been highly hardened. Such drills have great strength and wear out slowly.
- Golden color. These are drills coated with titanium nitride. They have a smooth surface to which chips do not stick well. They are used when working with jewelry, since there are almost no friction forces when working.
The color of the tool is considered an important characteristic of the drill.
Classification by size
Currently, drills for working with metal are produced in different sizes to work with products of any thickness. Modern production classifies cutting tools in three working sizes:
short series drills - their minimum length is 20 mm, maximum - 130 mm; diameter ranges from 0.3 to 20 mm.
elongated - produced in lengths from 19 to 205 mm and diameters from 0.3 to 20 mm.
long series drills - reach a length of 254 mm, minimum diameter - 1 mm (maximum - 20 mm). The long model is convenient for working with products that are thick and durable. Short cutting tools are used to drill neat, uniform holes in a thin product (for example, a metal plate).
Twist drills for metal: standard sizes and diameters
Tools of this type are used to perform most operations in industry and everyday life. At home, twist drills with cylindrical shanks are most often used, and in production - with conical shanks. The diameters and sizes of household and industrial metal drills differ.
Table of diameters and sizes of twist drills for metal with cylindrical shanks
Tools of this type are manufactured according to GOST 886-77. The following grades of steel are most often used.
- R6M5.
- R6M5K5.
- P18.
- H.S.S.
Photo No. 1: metal twist drills with cylindrical shanks
Standard diameters of metal drills with cylindrical shanks range from 1 to 31.5 mm. Tools with increased dimensions are manufactured according to special orders from shops and workshops.
Standard diameters and sizes of metal drills with cylindrical shanks are presented in the table below.
| Drill diameter | total length | Working length |
| 1 mm | 56 mm | 33 mm |
| 1.1 mm | 60 mm | 37 mm |
| 1.2 mm | 65 mm | 41 mm |
| 1.3 mm | ||
| 1.4 mm | 70 mm | 45 mm |
| 1.5 mm | ||
| 1.6 mm | 76 mm | 50 mm |
| 1.7 mm | ||
| 1.8 mm | 80 mm | 53 mm |
| 1.9 mm | ||
| 1.95 mm | 85 mm | 56 mm |
| 2 mm | ||
| 2.05 mm | ||
| 2.1 mm | ||
| 2.15 mm | 90 mm | 59 mm |
| 2.2 mm | ||
| 2.25 mm | ||
| 2.3 mm | ||
| 2.35 mm | ||
| 2.4 mm | 95 mm | 62 mm |
| 2.45 mm | ||
| 2.5 mm | ||
| 2.55 mm | ||
| 2.6 mm | ||
| 2.65 mm | ||
| 2.7 mm | 100 mm | 66 mm |
| 2.75 mm | ||
| 2.8 mm | ||
| 2.85 mm | ||
| 2.9 mm | ||
| 2.95 mm | ||
| 3.0 mm | ||
| 3.1 mm | 106 mm | 69 mm |
| 3.15 mm | ||
| 3.2 mm | ||
| 3.3 mm | ||
| 3.35 mm | ||
| 3.4 mm | 112 mm | 73 mm |
| 3.5 mm | ||
| 3.6 mm | ||
| 3.7 mm | ||
| 3.8 mm | 119 mm | 78 mm |
| 3.9 mm | ||
| 4.0 mm | ||
| 4.1 mm | ||
| 4.2 mm | ||
| 4.25 mm | ||
| 4.3 mm | 126 mm | 82 mm |
| 4.4 mm | ||
| 4.5 mm | ||
| 4.6 mm | ||
| 4.7 mm | ||
| 4.8 mm | 132 mm | 87 mm |
| 4.9 mm | ||
| 5.0 mm | ||
| 5.1 mm | ||
| 5.2 mm | ||
| 5.3 mm | ||
| 5.4 mm | 139 mm | 91 mm |
| 5.5 mm | ||
| 5.6 mm | ||
| 5.7 mm | ||
| 5.8 mm | ||
| 5.9 mm | ||
| 6.0 mm | ||
| 6.1 mm | 148 mm | 97 mm |
| 6.2 mm | ||
| 6.3 mm | ||
| 6.4 mm | ||
| 6.5 mm | ||
| 6.6 mm | ||
| 6.7 mm | ||
| 6.8 mm | 156 mm | 102 mm |
| 6.9 mm | ||
| 7.0 mm | ||
| 7.1 mm | ||
| 7.2 mm | ||
| 7.3 mm | ||
| 7.4 mm | ||
| 7.5 mm | ||
| 7.6 mm | 165 mm | 109 mm |
| 7.7 mm | ||
| 7.8 mm | ||
| 7.9 mm | ||
| 8.0 mm | ||
| 8.1 mm | ||
| 8.2 mm | ||
| 8.3 mm | ||
| 8.4 mm | ||
| 8.5 mm | ||
| 8.6 mm | 175 mm | 115 mm |
| 8.7 mm | ||
| 8.8 mm | ||
| 8.9 mm | ||
| 9.0 mm | ||
| 9.1 mm | ||
| 9.2 mm | ||
| 9.3 mm | ||
| 9.4 mm | ||
| 9.5 mm | ||
| 9.6 mm | 184 mm | 121 mm |
| 9.7 mm | ||
| 9.8 mm | ||
| 9.9 mm | ||
| 10.0 mm | ||
| 10.1 mm | ||
| 10.2 mm | ||
| 10.3 mm | ||
| 10.4 mm | ||
| 10.5 mm | ||
| 10.6 mm | ||
| 10.7 mm | 195 mm | 128 mm |
| 10.8 mm | ||
| 10.9 mm | ||
| 11.0 mm | ||
| 11.1 mm | ||
| 11.2 mm | ||
| 11.3 mm | ||
| 11.4 mm | ||
| 11.5 mm | ||
| 11.6 mm | ||
| 11.7 mm | ||
| 11.8 mm | ||
| 11.9 mm | 205 mm | 134 mm |
| 12.0 mm | ||
| 12.1 mm | ||
| 12.2 mm | ||
| 12.3 mm | ||
| 12.4 mm | ||
| 12.5 mm | ||
| 12.6 mm | ||
| 12.7 mm | ||
| 12.8 mm | ||
| 12.9 mm | ||
| 13.0 mm | ||
| 13.1 mm | ||
| 13.2 mm | ||
| 13.3 mm | 214 mm | 140 mm |
| 13.4 mm | ||
| 13.5 mm | ||
| 13.6 mm | ||
| 13.7 mm | ||
| 13.75 mm | ||
| 13.8 mm | ||
| 13.9 mm | ||
| 14.0 mm | ||
| 14.25 mm | 220 mm | 144 mm |
| 14.5 mm | ||
| 14.75 mm | ||
| 15.0 mm | ||
| 15.25 mm | 227 mm | 149 mm |
| 15.4 mm | ||
| 15.5 mm | ||
| 15.75 mm | ||
| 16.0 mm | ||
| 16.25 mm | 235 mm | 154 mm |
| 16.5 mm | ||
| 16.75 mm | ||
| 17.0 mm | ||
| 17.25 mm | 241 mm | 158 mm |
| 17.4 mm | ||
| 17.5 mm | ||
| 17.75 mm | ||
| 18.0 mm | ||
| 18.25 mm | 247 mm | 162 mm |
| 18.5 mm | ||
| 18.75 mm | ||
| 19.0 mm | ||
| 19.25 mm | 254 mm | 166 mm |
| 19.4 mm | ||
| 19.5 mm | ||
| 19.75 mm | ||
| 20.0 mm | ||
| 20.25 mm | 261 mm | 171 mm |
| 20.5 mm | ||
| 20.75 mm | ||
| 21.0 mm | ||
| 21.25 mm | 268 mm | 176 mm |
| 21.5 mm | ||
| 21.75 mm | ||
| 22.0 mm | ||
| 22.25 mm | ||
| 22.5 mm | 275 mm | 180 mm |
| 22.75 mm | ||
| 23.0 mm | ||
| 23.25 mm | ||
| 23.5 mm | ||
| 23.75 mm | 282 mm | 185 mm |
| 24.0 mm | ||
| 24.25 mm | ||
| 24.5 mm | ||
| 24.75 mm | ||
| 25.0 mm | ||
| 25.25 mm | 290 mm | 190 mm |
| 25.5 mm | ||
| 25.75 mm | ||
| 26.0 mm | ||
| 26.25 mm | ||
| 26.5 mm | ||
| 26.75 mm | 298 mm | 195 mm |
| 27.0 mm | ||
| 27.25 mm | ||
| 27.5 mm | ||
| 27.75 mm | ||
| 28.0 mm | ||
| 28.25 mm | 307 mm | 201 mm |
| 28.5 mm | ||
| 28.75 mm | ||
| 29.0 mm | ||
| 29.25 mm | ||
| 29.5 mm | ||
| 29.75 mm | ||
| 30.0 mm | ||
| 30.25 mm | 316 mm | 207 mm |
| 30.5 mm | ||
| 30.75 mm | ||
| 31.0 mm | ||
| 31.25 mm | ||
| 31.5 mm |
Table No. 1: standard sizes and diameters of twist drills for metal with cylindrical shanks
Dimensions and diameters of twist drills for metal with tapered shanks
Tools of this type are made according to GOST 10903-77 from steel grades P9, P18, P6M5, P6M5K5 and HSS. The diameters of twist drills for metal with conical shanks vary from 5 to 80 mm.
Photo No. 2: metal twist drills with tapered shanks
The exact size data is given in the table below.
| Drill diameter | total length | Cutting length |
| 5 mm | 133 mm | 52 mm |
| 5.2 mm | ||
| 5.5 mm | 138 mm | 57 mm |
| 5.8 mm | ||
| 6.0 mm | ||
| 6.2 mm | 144 mm | 63 mm |
| 6.4 mm | ||
| 6.5 mm | ||
| 6.6 mm | ||
| 6.8 mm | 150 mm | 69 mm |
| 7.0 mm | ||
| 7.2 mm | ||
| 7.4 mm | ||
| 7.5 mm | ||
| 7.6 mm | 156 mm | 75 mm |
| 7.8 mm | ||
| 8.0 mm | ||
| 8.2 mm | ||
| 8.4 mm | ||
| 8.5 mm | ||
| 8.8 mm | 162 mm | 81 mm |
| 9.0 mm | ||
| 9.2 mm | ||
| 9.5 mm | ||
| 9.8 mm | 168 mm | 87 mm |
| 10.0 mm | ||
| 10.2 mm | ||
| 10.5 mm | ||
| 10.8 mm | 175 mm | 94 mm |
| 11.0 mm | ||
| 11.2 mm | ||
| 11.5 mm | ||
| 11.8 mm | ||
| 12.0 mm | 182 mm | 101 mm |
| 12.2 mm | ||
| 12.5 mm | ||
| 12.8 mm | ||
| 13.0 mm | ||
| 13.2 mm | ||
| 13.5 mm | 189 mm | 108 mm |
| 13.75 mm | ||
| 13.8 mm | ||
| 14.0 mm | ||
| 14.25 mm | 212 mm | 114 mm |
| 14.5 mm | ||
| 14.75 mm | ||
| 15.0 mm | ||
| 15.25 mm | 218 mm | 120 mm |
| 15.5 mm | ||
| 15.75 mm | ||
| 16.0 mm | ||
| 16.25 mm | 223 mm | 125 mm |
| 16.5 mm | ||
| 16.75 mm | ||
| 17.0 mm | ||
| 17.25 mm | 228 mm | 130 mm |
| 17.5 mm | ||
| 17.75 mm | ||
| 18.0 mm | ||
| 18.25 mm | 233 mm | 135 mm |
| 18.5 mm | ||
| 18.75 mm | ||
| 19.0 mm | ||
| 19.25 mm | 238 mm | 140 mm |
| 19.5 mm | ||
| 19.75 mm | ||
| 20.0 mm | ||
| 20.25 mm | 243 mm | 145 mm |
| 20.5 mm | ||
| 20.75 mm | ||
| 21.0 mm | ||
| 21.25 mm | 248 mm | 150 mm |
| 21.5 mm | ||
| 21.75 mm | ||
| 22.0 mm | ||
| 22.25 mm | ||
| 22.5 mm | 253/276 mm | 155 mm. |
| 22.75 mm | ||
| 23.0 mm | ||
| 23.25 mm | ||
| 23.5 mm | ||
| 23.75 mm | 281 mm | 160 mm |
| 23.9 mm | ||
| 24.0 mm | ||
| 24.25 mm | ||
| 24.5 mm | ||
| 24.75 mm | ||
| 25.0 mm | ||
| 25.25 mm | 286 mm | 165 mm |
| 25.5 mm | ||
| 25.75 mm | ||
| 26.0 mm | ||
| 26.25 mm | ||
| 26.5 mm | ||
| 26.75 mm | 291 mm | 170 mm |
| 27.0 mm | ||
| 27.25 mm | ||
| 27.5 mm | ||
| 27.75 mm | ||
| 28.0 mm | ||
| 28.25 mm | 296 mm | 175 mm |
| 28.5 mm | ||
| 28.75 mm | ||
| 29.0 mm | ||
| 29.25 mm | ||
| 29.5 mm | ||
| 29.75 mm | ||
| 30.0 mm | ||
| 30.25 mm | 301/306 mm | 180 mm |
| 30.5 mm | ||
| 30.75 mm | ||
| 31.0 mm | ||
| 31.25 mm | ||
| 31.5 mm | ||
| 31.75 mm | ||
| 32.0 mm | 334 mm | 185 mm |
| 32.25 mm | ||
| 32.5 mm | ||
| 32.75 mm | ||
| 33.0 mm | ||
| 33.25 mm | ||
| 33.5 mm | ||
| 34.0 mm | 339 mm | 190 mm |
| 34.5 mm | ||
| 35.0 mm | ||
| 35.25 mm | ||
| 35.5 mm | ||
| 35.75 mm | 344 mm | 195 mm |
| 36.0 mm | ||
| 36.25 mm | ||
| 36.5 mm | ||
| 37.0 mm | ||
| 37.5 mm | ||
| 38.0 mm | 349 mm | 200 mm |
| 38.25 mm | ||
| 38.5 mm | ||
| 39.0 mm | ||
| 39.25 mm | ||
| 39.5 mm | ||
| 40.0 mm | ||
| 40.5 mm | 354 mm | 205 mm |
| 41.0 mm | ||
| 41.25 mm | ||
| 41.5 mm | ||
| 42.0 mm | ||
| 42.5 mm | ||
| 43.0 mm | 359 mm | 210 mm |
| 43.25 mm | ||
| 43.5 mm | ||
| 44.0 mm | ||
| 44.5 mm | ||
| 45.0 mm | ||
| 45.25 mm | 364 mm | 215 mm |
| 45.5 mm | ||
| 46.0 mm | ||
| 46.5 mm | ||
| 47.0 mm | ||
| 47.5 mm | ||
| 48.0 mm | 369/374 mm | 220 mm |
| 48.5 mm | ||
| 49.0 mm | ||
| 49.5 mm | ||
| 50.0 mm | ||
| 50.5 mm | ||
| 51.0 mm | 412 mm | 225 mm |
| 51.5 mm | ||
| 52.0 mm | ||
| 53.0 mm | ||
| 54.0 mm | 417 mm | 230 mm |
| 55.0 mm | ||
| 56.0 mm | ||
| 57.0 mm | 422 mm | 235 mm |
| 58.0 mm | ||
| 59.0 mm | ||
| 60.0 mm | ||
| 61.0 mm | 427 mm | 240 mm |
| 62.0 mm | ||
| 63.0 mm | ||
| 64.0 mm | 432 mm | 245 mm |
| 65.0 mm | ||
| 66.0 mm | ||
| 67.0 mm | ||
| 68.0 mm | 437 mm | 250 mm |
| 69.0 mm | ||
| 70.0 mm | ||
| 71.0 mm | ||
| 72.0 mm | 442 mm | 255 mm |
| 73.0 mm | ||
| 74.0 mm | ||
| 75.0 mm | ||
| 76.0 mm | 514 mm | 260 mm |
| 77.0 mm | ||
| 78.0 mm | ||
| 79.0 mm | ||
| 80.0 mm |
Table No. 2: sizes and diameters of standard twist drills for metal with tapered shanks
Diameters and sizes of core drills for metal
Core drills for metal are used to produce through holes with small depths but large diameters. They can reach 150 mm. The cutting depth varies from 5 to 50 mm.
Photo No. 3: core drills for metal
Study the design features of core drills in the diagram.
Image No. 1: design features of a core drill for metal.
Standard diameters and sizes of core drills for metal are presented in the table below.
| D | d 1 (limit trip according to A3) | d | b | Number of records |
| 16 | 11 | 4 | 8 | 3 |
| 20 | 15 | 6 | 12 | |
| 25 | 18 | 15 | 4 | |
| (30) | 24 | 21 | ||
| 32 | 10 | 20 | ||
| (36) | 28 | 24 | ||
| 40 | 32 | 28 | ||
| (45) | 36 | 32 | ||
| 50 | 42 | 38 | ||
| 75 | 68 | 64 | 6 | |
| 85 | 78 | 74 |
Table No. 3: standard diameters and sizes of carbide core drills for metal (GOST 17013-71)
Shank types
The tail part of the drill has different configurations - cylindrical, conical and hexagonal. Most often, cylindrical models are used in practice. They have a small feature: the diameters of the drill and shank may not match. Experts say that if you equip the drilling tool with a cylindrical shank of a slightly larger diameter, this maneuver will make the fixation stronger. There is also a minus - an increase in the recommended power of the tool. But the drill will not be damaged if such a drill jams during operation. Tapered shanks are suitable for drill bits in industrial drills. This is how workpieces are processed on factory machines. The hex shank tool holds well in special clamps and jaw chucks.
Which manufacturers can you trust?
The quality and service life of metal processing drills depends on the manufacturer. Craftsmen who use drills every day claim that good tools can be found both from domestic and foreign companies. Russian-made drills are wear-resistant, strong and durable, but, unfortunately, there are fewer and fewer of them on the market every year. Now products and “Zubr” are in demand. These brands produce inexpensive but reliable high-quality instruments. Drills and “ATTACK” have also proven themselves well. Among imported ones, professionals prefer metal cutting tools, Bosch, Haisser and Makita. Their characteristics are approximately the same: they can withstand extreme loads, work “for wear”, and wear occurs slowly. Good value for money. There are two more and Dewalt. Their products differ from others in their high drilling speed. The price of a tool depends on the country of manufacture, length, diameter, strength and what it is intended for.
| Rating of the best drills for metal processing |
| Bosch 2607017154 |
| Attack N802-6 |
| Wurth Zebra Spiralbohrersatz HSS |
| Anchor 25219 |
| Metabo Bestell-Nr. 27 094 HSS-G |
| AEG HSS-G 4932430416 |
| Bison MET-SH H19 R6M5 |
| DeWALT DT7926 Extreme2 HSS |
| Hawera HSS-C Spiral Bohrer GQ-32692 |
| Irwin TurboMax 10503992 |
On what basis should you choose a drill?
When choosing a drill, focus on the following indicators:
Weight - a quality drill should not be light; Experts recommend buying cutting tools weighing 14 grams or more. If the store doesn’t have scales, rely on your feelings.
Strength - for a metal product to yield to a drill, it must be strong; You can check the strength using a glass bottle. Scratch something on the glass with the working surface of the tool - there should be impressive scratches on the bottle and glass chips around them.
Workmanship - craftsmen advise using drills made by milling followed by grinding.
Sharpening angle - for metal it is better to choose drills sharpened at an angle of 130-135 degrees.
Steel grade - buy tools that will fit your equipment (drill, drill press, etc.).
Sharpening rules
The sharpening angle of a drill is how sharp the working surface and edges are sharpened. According to the technology of execution, turning can be single-plane and conical. Using single-plane technology, small drills up to 3 mm in diameter are sharpened. To sharpen such a cutting tool, you need a special emery wheel. The drill is brought to the circle at an angle of 30 degrees so that its cutting part comes into contact with the emery surface of the circle. Conical sharpening is considered more difficult. This method is used for drills with a diameter of more than 3 mm. The tool must be held with both hands at the same time by the shank and the spiral part and rotated during the grinding process, giving it a cone shape. Drills are sharpened at a certain angle. The sharpening angle depends on the purpose of use. For example, to work with products made of bronze or high-strength steel, the sharpening angle must be at least 120 degrees, the optimal option is 130-140. And for drilling soft metals, equipment with a sharpening angle of 100 will be sufficient.
Typical drill sets for various materials
Initially, when developing the design and materials, leading manufacturers adopted an approach in which a set of drilling tools of different diameters was oriented towards use for drilling a specific material. Therefore, all microdrills in the set differ only in diameter. The sharpening angle of the edge, the inclination of the spiral grooves for chip removal and the cutting speed are exactly the same for all elements of the set.
Sets of microdrills for drilling steel and alloys are distinguished by the tool material used:
- Drills made of HSS-E steel, alloyed with cobalt up to 5%, for processing alloyed, carbon, hardened high-strength steels;
- Sets of microdrills made of HSS-G steel for processing lighter materials - graphite, copper, aluminum, all types of cast iron. The drill is subjected to particularly precise multi-pass grinding, so the resulting hole has an accuracy class of A, with a tolerance of h8;
- Ordinary microdrills made from high-speed steel HSS-R are produced both in single versions and in the form of a set, with a range of diameters from 0.1 to 3 mm. This tool can be used for drilling wood, soft polymers and composites.
Micro drills cannot be classified as ordinary metal-cutting tools; most often, sets of small diameter drills, up to 1 mm, are used by engravers and repairmen. Such a kit is not cheap, so the best option would be to buy a high-quality tool from a well-known brand, for example, Bosch or Heller.
High quality German drills
is rightfully considered the world's first manufacturer of drilling tools, both for domestic purposes and in industrial production. The quality of Heller set drills is determined by the very precisely selected characteristics of the cutting edge and the HSS high-speed steel used.
The standard form of sale of the kit is a case, a metal box with a folding tripod in which the drills are located. For household purposes, the tool can be sold in plastic packaging with mandatory marking of the material and a number of drill diameters included.
For professional activities, the Heller HSS Cobalt and Heller Prefix HSS-Super kits are used. In addition to a large selection of tool diameters, the drills presented in the Perfix set are made using triple center grinding technology.
Russian drilling tools
Among the numerous products of machine-building plants that produce metal-cutting tools, both of their own design and of licensed type, we can note the products of young and dynamically developing ones. You can evaluate the quality of manufactured drills for a wide range of applications using a set for drilling steels and alloys, with a tensile strength of up to 800 MPa.
The set is called “Technician” and contains 370 units of tools, assembled in 19 sections of a metal case. The drills are made of steel R4M2 in accordance with the requirements of GOST 10902-77 for accuracy class B1. This set of drills for metal “Bison” costs 49 thousand rubles for one set. According to the manufacturer, the set is designed for use in repair shops, service stations and small mechanical assembly areas.
In addition to general-purpose tools, it offers the 429625H20P set under the trade names “Expert” and “Met-Sh”. It includes ten and twenty drills, respectively, with a diameter of 0.33 mm to 1 mm. The tool is made from inexpensive high-speed steel R6M5. According to the manufacturers, the microdrills included in the set provide high positioning accuracy due to the presence of a cross-shaped reverse sharpening of the cutting edge.
The cost of the kit does not exceed 500 rubles; it is designed for use in repairing printed circuit boards of small household appliances.
Drill set made in China
Most often, to repair household appliances, small appliances and tools, you buy a simple and relatively inexpensive drilling kit made in China from an unknown company, as in the photo.
A set of 150 units of drills of various diameters, from 0.4 mm to 3.2 mm, is placed in a gray plastic case. The top cover is made of transparent plastic, with size and diameter markings on the surface. There are no markings on the tool itself, so if the lid is slightly opened, or the box is shaken vigorously, most of the drills will fly out of their cells, and it will be very difficult to sort them by size.
The drills are made and sharpened according to the old Soviet pattern with a centering belt on the edge. The quality of sharpening can be seen from the photo. The tool life will be a maximum of 4-5 drills. The cost of the set is 560 rubles.
What devices are used for sharpening drills?
You can sharpen a dull cutting tool on a special industrial machine. It can be professional or domestic. The first is used for mass sharpening of drills in enterprises or professional firms. The second one is convenient to use at home or in the garage. A metal drill can be sharpened with a highly specialized machine (only for one type of equipment) and a universal one, which is used to work with other types of drills. Depending on the type of work, sharpening tools can be electrical or mechanical. You can make a device for sharpening cutting tools yourself or purchase it in a special store. Professionals prefer to use such machines as “REZER”, as well as domestic devices, “Caliber”, “Kraton”.
What is the difference between drills for metal and wood processing?
Cutting tools for metal and wood have several differences: - drills for metal do not have a center peak (a sharp corner or pin necessary to prevent the tool from jumping off during operation). — drills for metal surfaces are made of durable alloys so that they can easily drill holes in metal. — tools for metal are black or gold (yellow) in color. For drilling wood and chipboard products, the strength of gray ones is sufficient. — a drill for metal has a sharpening angle of at least 100 degrees. But for wood, 90 degrees or less is enough.
