Reikäporausmenetelmä

Reikäporausmenetelmä, often translated as reaming or bore drilling, is a mechanical process used to enlarge and finish an existing hole. It involves a reamer, a multi-fluted cutting tool, that is passed through a pre-drilled or bored hole. The reamer has precisely ground cutting edges that remove a small amount of material from the hole's surface.

The primary purpose of reaming is to achieve a higher degree of accuracy in terms of hole diameter, roundness, and surface finish compared to what can be obtained by drilling alone. It corrects minor inaccuracies left by the initial drilling operation, such as out-of-roundness or slight taper. Reaming is typically used for finishing operations where tight tolerances are required.

Reamers come in various types, including straight-fluted, helical-fluted, and rose reamers, each suited for different materials and applications. The cutting speed and feed rate used during reaming are generally slower than those used for drilling to ensure a clean cut and a smooth surface. The amount of material removed by a reamer, known as the "reamer allowance," is usually very small, often measured in fractions of a millimeter or thousandths of an inch. This controlled material removal is key to its precision.