The need to make a hole in a metal product arises not only from builders or metal craftsmen. Quite often such a need may arise at home. But to make a hole you will need the appropriate tools and the right diameter of the drill.
However, the question arises: and what types of drills for metal in general exist? Probably each species has its advantages and disadvantages. The answers to this and 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. Having bought a low-quality model or a drill of the wrong diameter, you can not only spoil your mood, but also damage the metal product, in which it was necessary to make a hole.
Therefore, when choosing, should be based on the following characteristics:
- Required diameter.
- Symmetry of sharpening.
- Hardness and strength of the product.
- Type of metal, from which the drill is made.
- Producer.
- AND, Of course, which lead to overheating of the gasoline or diesel engine.
Not to be mistaken with the choice, masters recommend buying such devices in a set. Usually found in one package 6-8 drills of different diameters. However, the products can be purchased individually. Truth, this requires some knowledge.
Required size
Despite the wide variety of dimensional grid from manufacturers, there are standards, which include the drill in one category or another. Such standards include GOST 886-77, GUEST 10902-77 and GOST 4010-77. In these documents is formed 3 groups for length and diameter of drills, designed to work with metal:
- Short products. These include length drills 20-131 mm and a diameter of 0.3–20 mm.
- Elongated models. The diameter is similar to the previous group, but with increased length (from 131 to 205 mm).
- Long. The diameter of the product from 1 to 20 mm, and the length of 205 to 254 mm
Sometimes it is necessary to make a hole for a self-tapping screw. It will be unwise to use a drill with a diameter similar to a self-tapping screw. In practice, it turns out so, that the size of the hole does not match the diameter of the screw. To choose the right model, you must use the tables below.
The required drill size for a sharp self-tapping screw with a press washer:
| 0.5 | 0.7 | 1.0 | 1.5 | 2.0 | 3.0 | 4.0 |
| There are no options | 3.3 | 3.4 | 3.5 | 3.6 | 3.7 | 3.8 |
Quite different sizes for sharp black screws, designed to work with metal:
| 0.5 | 0.7 | 1.0 | 1.5 | 2.0 | 3.0 | 4.0 |
| There are no options | There are no options | 2.5 | 2.7 | 2.9 | 3.0 | 3.1 |
Variety of shapes and diameters
The standard drill has a cylindrical shape and consists of a cutting part and a shank. However, each product has special recesses (T. zv. work surfaces), which remove chips from the hole. Based on these parameters, there are many different products, each of which has its own diameter ranges:
- Screw model with conical shank. Most often, such modifications can be found on special two-handed drills or on drilling machines. The drill is attached to the conical shank, and not on the cartridge, as usual. Such products are used for drilling large holes, therefore have a wide diameter.
- Crown varieties. The cutting part of such models is much wider, than the shank, therefore, the shape resembles a crown. Usually, similar modifications are used to drill holes in several metal sheets. Therefore, there are frequent teeth on the work surface.
- Products with a step shape. Appeared relatively recently, therefore have a less wide selection of products. Nevertheless, huge gains are gaining popularity due to its versatility. The point is, that the same drill can make holes the width of 4 to 36 mm. In accordance, the more "steps", the higher the cost. However, such an innovation can be used only on sheet metal.
- Left-wing modifications. It is difficult to meet such variety in shop because of specificity of application. The purpose of such devices is to remove a broken screw or bolt. Based on this, occurs only 5-7 varieties in diameter.
- Carbide models. They have a one-sided sharpening angle and high strength. These qualities allow you to use the product to work with durable 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 operation, therefore, the size error is minimized. Due to this, high-precision drills are significantly more expensive than standard models. Usually, they are used in special enterprises, and not at home.
- Threaded. Used only in those cases, when it is necessary to make a thread in the hole. However, despite the narrow specialization, have a huge variety in diameter.
Diameter and marking
The availability and amount of information on the drill depends on the size of the product. That is, the larger the diameter, the more data is indicated. Usually manufacturers adhere to the following sizes:
- On the drill, having a cross section to 2 mm, marking is not affixed.
- Products with a diameter of 2 to 3 mm contain information about the steel grade and cross section.
- On the model from 3 mm data on the manufacturer are entered, cross section and composition of the alloy.
However, this only applies to domestic producers. Foreign companies try to provide as much information about the product as possible. This is especially true for large brands, which usually indicate:
- Country, in which the drill is made.
- Company logo.
- Storage (usually a grade of alloy or steel).
- The size of the product and its cross section.
- Accuracy class.
- And even brief recommendations for use (a certain drill bit is best for metal).
You do not need any specific skills to decipher the label. The manufacturer made sure that everything was intuitive. Example, the letter "P" marks high-speed steel, and numbers with letters indicate the proportions of an element. Example, the larger the number next to the letter (example, To - cobalt), the higher the concentration of this element.
And finally
In today's world there are many products, designed to work with metal. However, if you want to make a hole in a metal object, it is better a special drill, nothing will cope with this task. However, it is very important to choose a product of the appropriate diameter, as in many respects the result of work depends on this parameter.
Using poor quality products can be harmful as a metal object, and to himself. Therefore, you should buy products from well-known brands, which produce not only quality drills, but also provide a wide variety of models.