Reaming

a method of machining holes by cutting (after drilling and countersink reaming) with a multiblade cutting tool called a reamer. As a result of rough reaming, an allowance of not more than 0.5 mm in diameter is removed, providing surface roughness of class 7 and a precision of class 3. In finish reaming, an allowance of not more than 0.2 mm is removed, providing a surface roughness up to class 9 and a precision up to class 2.