The purpose of any drill is to create different types of recesses and holes in a given material. This process occurs due to the rotation of the cutting element around its axis. In addition to creating new holes, using these tools, you can also expand old ones that have a small diameter. According to their design, application and production method, all types of drills have noticeable differences. Consider them in more detail.
Classification according to the type and shape of the working part
Due to the different types of tasks and functions, the elements have a different shape of the working part and are classified as follows:
- Screw type drill. Its second name is spiral. It is the most common, because in everyday life it is used most often. This tool, the length of which is from 5 to 20 or more centimeters, will help in drilling both wood and other types of materials: metals, ceramics, concrete. Line of spiral modelsinstruments are available in diameters from 0.1 mm to 3 cm.
- Drill flat type. It is shaped like a feather. This feature gave him another name - feather. First of all, it is used to create deep holes of a relatively large diameter. The cutting element of such a tool is made in the form of a spatula.
- To perform a deep drilling robot, long products are used that have two screw channels. A special fluid flows through them, cooling the tool during the working process. In most cases, the channels are placed inside the drill.
- There is also such a view as a one-sided cutting drill. It is used only in cases where the future hole must be made with high accuracy. With a single reference plane and the location of both cutting edges on the same side of the axis, the result of work with this tool is of high quality.
- Drill type ring. The structure of this type is interesting in that it is hollow inside. Thanks to this design, a narrow ring comes out during drilling. These types of drills have another name - crowns.
- To make a center hole, you can use the so-called centering product. It's available at any hardware store.
As a result, we can conclude that there are various types of drills. And their purpose is also different. Let's look at sharpening methods.
Types of sharpening drills
Having considered the types and shapes of work surfaces, it is necessary to reveal the issue of sharpening these elements. The process, or rather its type,depends entirely on the tasks to be performed by this tool.
There are the following types of sharpening:
- Ordinary, spiral. It is used for work with steel, non-ferrous metals, plastics.
- For cast iron. The name speaks for itself - for work with a mixture of cast iron.
- Transverse undercut on the edge. For all types of drilling work.
- With center point. For work with soft materials.
- Cone shape with subdot.
- Processing with pointed bridge and main blade for adjustment. Applicable for strong steel.
Classification by shank design
There is a classification of drills, the main criterion of which is the structure of the back part - the tool shank.
According to this classification, there are the following types of instruments:
- Cylindrical type.
- Tapered.
- Faceted. With six, four or three edges.
- SDS products.
Production technology
Some types of drills are made from a solid piece of metal. These include instruments whose diameter exceeds 8 mm. Drills up to 6 mm in diameter are made from alloys.
This is a special steel, which is also called high-speed. Those types of tools whose diameter exceeds 8 mm are made by welding. The shank of such products is made from an alloycarbon steel. And the cutting part is made of high-speed alloy steel. For processing fragile and brittle materials (soft wood, some metals), a drill with carbide inserts is used. Such tools are equipped with grooves of various shapes. There are straight, screw and beveled types.
Classification by hole shape
The shape of the holes produced is another method for classifying products. According to this characteristic, they are divided into the following types:
- Conical shape.
- Square.
- Stepped.
- Cylindrical.
Classification by coverage
The material that the drill is coated with is a very important characteristic of the tool.
The coating determines the durability and performance of a given tool. According to this parameter, the following products are available:
- The budget option for coating the drill is an oxide film. The function of this coating is to protect the tool from corrosion and protection from overheating. Thanks to the oxide film, the service life is increased.
- Ceramic type coating. It is made from titanium nitride. Due to this, this type of coating increases the service life of the tool by three times. But there is one downside. Such drills must not be sharpened.
- Titanium-aluminum nitride was created as a derivative of the previous type of coating. In this case, the drill resource is increased by 5 times.
- Similar in action to titanium aluminum nitride is titanium carbonitride.
- The strongestand wear-resistant are tools that are coated with diamond coating.
Types of metal drills
Spiral products are great for working on non-ferrous metals, cast iron and steel.
Chips that are generated during machining go through the machined grooves. Drills for metal work differ not only in the material and coating from which they were made, but also in the type of shank. To determine the quality of a tool, you do not need to be a high-class specialist. It is enough to look at the color of the coating. Low quality tools have a gray tint. If the color of the product is black, this is a sign of a higher quality. A drill with a bright golden hue indicates that the tool is coated with titanium nitride and its quality is excellent. Speaking about the strength of the material itself, from which the drill is made, it can be noted that it must be carbide. After all, metals themselves have high strength. Therefore, for their processing, a material is needed that has greater strength.
For woodworking
When you need to make several small holes in wood material, the simplest twist drill will do. For high precision work or when a large hole needs to be made, special woodworking tools are used. They are made from tool steel, carbon-containing or alloyed. Such a tool is not used for metal work.
Types of wood drill bits:
- Spiral type.
- Spiral.
- By pen type or pen.
- Tools for woodworking.
- Forsner drill.
For working with concrete
To work with more durable surfaces (concrete, brick, stone), you will need a very strong product that has a hard tip. The alloy from which the types of drills for concrete are made has high strength characteristics. The work of such a tool is carried out using shock-rotary mechanisms (perforator). Most often, SDS shanks are used for this type. To carry out a certain drilling, the types of drills must be selected of the appropriate type. To make a small hole in hard concrete, a hard-tipped auger drill should be used. For large holes it is necessary to use special toothed carbide bits. As a rule, they are coated with diamond dusting. This is necessary for greater efficiency and longer service life.
