How to choose a drill bit for metal

Drill for metal performs the functions of a cutting tool with a rotational movement of cutting and axial feed. With its help holes are made in solid materials, and also expand and enlarge the ones already available.

All drills can be divided into two types: spiral and perovy. Each type has its own advantages and weaknesses.

Especially popular among consumers uses a spiral drill for metal. These devices are made in the form of a cylindrical rod, the working part of which has spiral grooves serving for chip removal. The slope of the notches varies up to 45 degrees. The edge of the drill is represented by a conical shape. All spiral species have a conical, cylindrical or hexagonal shank. This tool is characterized by strength, reliability and long life. High cost is the main disadvantage, which has a spiral drill for metal. The price also depends on the size.

Perforated or flat drills have a fairly simple design, they are resistant to tilting during operation, and their production is of low cost. A metal drill bit can be single- or double-sided. This difference is due to the method of sharpening their cutting edges. In this type of device, the cutting part has two edges, which are located at the same distance from the center of the axis of the rod, and at work form angles from 45 to 90 degrees.

To determine the size of the drill, it is sufficient to measure the width of the blade. The thickness of the cutting edge feather depends on the diameter of the entire tool. The main drawback of the perforated drill is that there is no automatic chip removal during operation. As a result, the cutting edges are damaged, and the drill bit for the metal often has to be removed from the hole. In addition, in the process of work, perovy drills sometimes lose direction, and when they recenter, the diameter decreases.

When choosing a tool, you should pay attention to the cutting speed. The optimal combination of the feed of the rod and the speed of its rotation makes it possible to achieve maximum productivity. The cutting speed determines the time at which the outer points of the main cutting edge go their way. As practice shows, drills with a diameter of up to 2 centimeters can work without rewinding for about 15 minutes, and at a size of more than 4 cm - about an hour and a half.

The cutting speed, in the first place, depends on the material from which the drill for metal is made. When using high-speed steel, the productivity of the tool is higher than that of rods made of carbonaceous material. Thus, it is better to buy carbide drills.

When choosing a tool, you should consider the diameter of the drill and the depth at which it will enter the metal. It should be remembered that with a greater recess the urgency of chip removal increases, and there is a significant heating of the cutting edges.