Circular solid bonded abrasive tools with central through-holes, made from abrasives and binder resins. Angle grinders are a type of abrasive tool widely used due to their versatility and high usage rate. They rotate at high speeds and can perform rough, semi-finishing, and finishing grinding on the outer and inner circles, flats, and various profiles of metal or non-metal workpieces, as well as slotting and cutting. There are numerous types of angle grinders. They can be categorized by the abrasive material used, such as common abrasives (corundum and silicon carbide) wheels and natural abrasive super-hard wheels (diamond and cubic boron nitride) wheels; by shape, including flat wheels, bevel wheels, cylindrical wheels, cup wheels, and disc wheels; and by binder, such as ceramic wheels, resin wheels, rubber wheels, and metal wheels. The characteristic parameters of the wheels include abrasive material, viscosity, hardness, binder, shape, and size. Since wheels often operate at high speeds, they should be subjected to a rotation test (to ensure they won't crack at high working speeds) and a static balance test (to prevent vibration during operation) before use. After a period of use, the wheels should be dressed to restore their grinding performance and correct geometric shape.