Step drill

A step drill bit (also known as a cone bit) is a tapered drill bit with multiple diameter steps. A single tool can be used to drill holes of various sizes, enlarge existing holes, and deburr them at the same time. It is primarily designed for thin materials such as sheet metal, pipes, profiles, and plastics.

For stainless steel (V2A/Inox), an HSSE cobalt step drill bit with a TiAlN coating is the right choice - it is heat-resistant and stable. The working method is important: low speed, even feed rate and good cooling. Spiral point versions cut into stainless steel more easily and with less vibration than straight point versions.

No. Step drill bits are designed for thin-walled material such as sheet metal, tubing, and profiles—the wall thickness should be less than the height of the respective step. For thick solid material, use a standard twist drill bit and enlarge the hole in steps if necessary. This keeps the hole round and prevents the step drill bit from being overloaded.

Straight-fluted step drill bits are more affordable and suitable for thin sheet metal, plastic, and wood. Spiral-fluted versions actively clear chips, cut more easily, and run more smoothly—a clear advantage when working with stainless steel, steel, and larger diameters. For clean results in metal, the spiral-fluted version is worth it.

This depends on the hole sizes you frequently need. For electrical and sheet metal work, 4-12, 4-20, or 4-30 mm cover most cases; for large openings, there are versions up to 60 mm. A set with multiple ranges offers the most flexibility. Make sure that the desired size is available as its own step.

Work at low speed, feed evenly, and cool when drilling metal. Because the step drill bit enlarges the hole gradually, the next step automatically deburrs the hole—simply keep drilling until you have completed the desired step. A backing board and moderate pressure prevent the sheet metal from tearing out.