Introduction to common drill types
Whether it is a drill for normal decoration or a drill for construction, it has a variety of types. Each type of drill has its own structural characteristics, and these structural characteristics determine the bit or limit of use of these drills. So, in general, what are the common types of drill bits? twist drill Twist drills are the most widely used hole machining tools. Usually the diameter ranges from 0.25 to 80 mm. It is mainly composed of the working part of the drill bit and the handle. The working part has two spiral grooves, which are shaped like twists, hence the name. In order to reduce the friction between the guiding portion and the wall of the hole during drilling, the twist drill is gradually reduced in diameter toward the shank and has an inverted cone shape. The helix angle of the twist drill mainly affects the size of the rake angle on the cutting edge, the strength of the blade and the chip removal performance, usually 25° to 32°. The spiral groove can be processed by milling, grinding, hot rolling or hot extrusion, and the front end of the drill bit is sharpened to form a cutting portion. The standard twist drill has a cutting edge angle of 118, a transverse blade angle of 40° to 60°, and a relief angle of 8° to 20°. For structural reasons, the rake angle is large at the outer edge and gradually decreases toward the middle, and the rake angle is a negative rake angle (up to -55°), which is squeezed during drilling. Flat drill The cutting part of the flat drill has a spade shape, a simple structure, a low manufacturing cost, and the cutting fluid is easily introduced into the hole, but the cutting and chip discharging performance is poor. The structure of the flat drill is both integral and assembled. The monolith is mainly used for drilling micropores with a diameter of 0.03 to 0.5 mm. The assembled flat drill blade is replaceable and can be internally cooled. It is mainly used for drilling large holes with a diameter of 25 to 500 mm. Deep hole drill Deep hole drills generally refer to tools that machine holes with a hole depth to hole ratio greater than 6. Commonly used are gun drill, BTA deep hole drill, jet drill, DF deep hole drill and so on. Nesting drills are also commonly used for deep hole machining. Reaming drill Reaming drills have 3 to 4 teeth and are more rigid than twist drills to expand existing holes and improve machining accuracy and finish. Drill The boring drill has a large number of teeth, and the hole end is processed into a desired shape by a forming method for processing the countersunk holes of various countersunk screws or flattening the outer end faces of the holes. Center drill The center drill is used for drilling the center hole of the shaft type workpiece. It is essentially a composite of twist drill and boring drill with a small helix angle, so it is also called a composite center drill. The above is a detailed introduction to the types of common drill bits. Introduced these kinds of drill bits, friends should also have a general understanding of the structural characteristics of these drill bits, although most of the places now use twist drills, but it is necessary to understand other drill bits. After all, although the twist drill is widely used, it also has its own limited place. At this time, we need to use other drill bits to help ourselves. The most important thing is to use each type of drill bit where it is needed to get the most out of it. Editor in charge: Wang Zhen Gate Latch,Gate Latch Hardware,Gate Lock Latch,Double Gate Latch Jiaxing Gates Hardware Products Co.,Ltd , https://www.jxgateshardware.com