Kennametal Inc.
Step drill

Abstract:

The invention relates to a step drill having a shaft section extending along a longitudinal axis of the step drill and a cutting section with a cutting tip, and having a chip-breaking geometry which comprises a concavely curved surface and is configured such that ribbon chips are broken on the concavely curved surface during rotation of the step drill, whereby the chip-breaking geometry is disposed on a reaming step of the step drill.