A step drill bit is a specialized tool designed to drill holes of varying diameters in thin materials, typically sheet metal. Its conical shape features multiple steps, each a different diameter, allowing the user to create holes of precise sizes incrementally. Using this type of bit avoids the need to change drill bits for each hole size. An operator can drill multiple diameter holes with the same bit.
This tool offers several advantages. It minimizes the risk of material deformation or “walking” of the drill bit, a common problem when drilling thin sheets. Furthermore, its self-deburring action often eliminates the need for secondary deburring processes. The gradual increase in diameter also reduces the stress on the material being drilled, leading to cleaner holes and prolonged tool life. Originally designed for metalworking, its usage has expanded to include plastics and other materials where clean, stepped holes are required.