A grinder is a mechanically powered hand tool featuring a rotating abrasive disc. The disc is mounted at a right angle to the motor and turns at a very high rate of speed. This tool is typically utilized for grinding, cutting, or polishing metal, concrete, tile and other hard materials. Angle grinder discs may be firm and abrasive for grinding and cutting tasks or smooth and flexible for sanding and polishing. This powerful tool can be quite dangerous and precautions must be taken to ensure safe operation.