Electric tools mainly include electric drill, electric hammer, impact drill, curved wire saw, angle grinder, dolomite machine, electric circular saw, cutting machine, electric planer, grinding machine and its related accessories. The function of electric drill is mainly used for drilling tools on wood, metal materials and plastics. When it is equipped with forward and reverse switch and electronic speed regulating device, it can be used as an electric screwdriver. Electric hammer is mainly used in masonry, concrete, artificial or natural stone drilling power tools, generally has impact, the second gear of the electric drill conversion part type has the function of chisel, active impact. The impact drill can open holes on brick wall, cement wall, wood and metal, with key chuck. It has the functions of impact and electric drill second gear conversion, some with forward and reverse rotation and electronic speed regulation.

he needle roller bearing is equipped with thin and long rollers (roller diameter D ≤ 5mm, L / D ≥ 2.5, l is the roller length), so the radial structure is compact. Its inner diameter and load capacity are the same as those of other types of bearings, and the outer diameter is small, which is especially suitable for the support results with limited radial installation size. The bearing without inner ring or needle roller and cage assembly can be selected according to different application occasions. At this time, the journal surface and shell hole surface matching with the bearing are directly used as the inner and outer rolling surface of the bearing. In order to ensure the same load capacity and operation performance as the bearing with ring, the hardness, machining accuracy and surface quality of the raceway surface of the shaft or outer shell hole shall be similar to that of the bearing ring. This kind of bearing can only bear radial load.

In use, attention should be paid to the maintenance of the screw driver. The blade of the screw driver must be properly ground, and the two sides of the blade should be parallel as far as possible. If the blade is tapered, the blade will easily slide out of the screw slot when turning the screwdriver. For the head of the screw driver, be careful not to grind too thin, or grind into other shapes. In addition, when grinding the screw driver on the grinding wheel, special care should be taken. It will soften the blade of the screw driver because of overheating, and it is better to wear goggles when grinding.

In terms of appearance, good quality wire cutters should be beautiful and generous, with even edges and even jaws, that is, good mouth and good teeth. In terms of internal quality, it mainly depends on whether the clamp shaft is flexible and whether the cutting edge of the pliers is moderate. Take steel wire or iron wire as an example, it can be easily cut, and the jaw is better without breaking or collapsing. When twisting the wire, the jaw is better. At the same time, we need to understand that the internal quality of the main process in the fire, the fire is easy to fall off the block, small fire is easy to collapse the jaw.