Hollow drill for drilling small diameter deep drill holes has two or more end cutters and a cutting part which has a larger diameter than its shaft

摘要

The drill is designed with its cutting part (2) having a larger diameter than its shaft (5). It has two or more end cutters (3). The core bore in the region of the cutting part is smaller than the core bore over the rest of the drill length and has in the region of the cutting part coolant grooves.