Grinders are tools or machines used to shape, sharpen, or polish materials, typically metal or wood. They work by using a rotating abrasive wheel or disk to remove material from the surface of an object. Grinders come in various types, including bench grinders, angle grinders, and surface grinders, each designed for specific tasks. In addition to industrial applications, grinders are also popular in the culinary world, where they are used to grind spices, coffee beans, and meats. A common kitchen grinder is the coffee grinder, which allows users to achieve the desired coarseness for brewing.