Drill cutting tool is axial withfeed and rotary cutting motion. It is used to make holes in the solid material for boring or increase the existing holes, as well as obtaining the recesses. How to choose a drill: Drills for metal, Drills on a tree? Consider the recommendations of experts.
All drill can be divided into two types: spiral, feather, and each type has its own advantages and weaknesses. Especially popular among consumers twist drills. They are made in the form of a cylinder rod, whose working part is equipped with two helical grooves that serve to chip removal. The inclination of the grooves varies between 10-45 degrees. The working edge of the drill is designed as a conical shape. Twist drills can be tapered, cylindrical and hexagonal shanks.
This type of drill is characterized by long life and high reliability. These shortcomings can be attributed only to the relatively high cost.
Features feather drills
Flat or Feather drills are simpledesign, besides their production is characterized by a small value, and in the work they are resistant to warping. Perov drills can be one-sided and two-sided: the difference is due to the form of sharpening their cutting edges. In drills feather portion has two cutting edges which are arranged symmetrically with the axis of the drill, and cutting to form at the corners 90, 75, 50 or 45 degrees. To measure the diameter of the drill bit to know the width of the blade is sufficient. The cutting edges have a thickness of the pen, which depends only on the diameter of the drill.
At the intersection of the cutting edges form a directline, called a bridge or transverse edge. The main disadvantage of feather drill - is no automatic withdrawal of chips during drilling, which leads to deterioration of the cutting edges, and the need for frequent curing of the drill hole during drilling. In addition, when working Feather drills may lose direction, and when regrinding their diameter decreases.
If you want to Choose the Right DrillIt is important to take into account the cutting speed. When choosing the optimum combination of drill feed and speed of rotation can reach maximum performance. The rotation speed is revolutions per minute. At its core, the speed is the way, which are outside the point of the cutting edge of the drill, it is measured in meters per minute.
The optimum cutting speed during drillingis the speed by which during prolonged operation without regrinding drill (10 min - 1.5 hours), a high performance. Practice shows that at 2 cm diameter drill it can operate without regrinding quarter of an hour, if the diameter is between 2.5-3.5 cm, while the half-hour, and when the drill diameter is greater than 4 cm, it can handle a half hour without requiring regrinding.
Permissible cutting speed during drillingIt depends on the quality of the material from which made the drill. Therefore, when choosing components, take some time to determine how well the material used for its manufacture. When using high-speed steel, while the cutting speed may be higher than that of drills made of carbon steel.
It is important to take into account the drilling depth and the diameter of the drill
The depth of drilling is an importantindicator when choosing a drill. Remember that with increasing depth of the hole increases the relevance of chip removal, and increases the friction leads to increased heating of the cutting edges. Therefore, the rate can be higher for shallow hole drilling than deep.
Depending on the purpose of holes, theirdiameters may vary: by scanning, through-blind, threaded, etc. Interestingly, in each of these cases, for the same diameter drill holes of different diameters are necessary! It is important to consider that during drilling the drill hole in contact with the edge and increases its size. There averages development drill holes. Therefore, if you need to get very precise hole diameter, it is important choose a drill or a drill for metal woodwork values given design.
The main features of the selection of drill bits, you can go to the hardware store in the full confidence that you can find the right "ammunition" for their drills.