A reamer is a machining tool that is used to make existing drilled, bored or cored holes more precise and to improve their finish. It is mainly used in metalworking.
A reamer is used as a hand tool and in spindles of machine tools, such as drill presses and milling machines.
The adjustable hand reamer is used for unbroken holes. It features disposable blades that slide along a tapered groove. The straight precision reamer is self-centering and is used to make minor hole enlargements. It removes the imperfections left by drills and other tools, creating a hole that is closer to one suited for a theoretical perfect cylinder.