Bosch Step Drill Bit: Fast, precise stepped holes from 4

For those who value precise hole sizing above all else, Bosch Step Drill Bit places a 4–39mm stepped range into a single HSS cutter. Practical for neat knockouts in thin metal and plastics, the single-shank layout speeds repetitive work and reduces time spent changing tools.

⚡ At a Glance

• Cutting Range: Stepped sizes from 4 mm up to 39 mm
• Optimised for: Sheet-metal work, cable gland holes and general workshop resizing tasks
• Trade-offs for: Installers needing holes larger than 39 mm; attempting a 45 mm knockout will stop at 39 mm and force use of a hole saw or larger cutter

High-speed steel step cutter covers 4–39 mm and uses a 10.0 mm shank with a 107 mm overall length. Weighs 0.595 pounds (roughly the weight of a small paperback novel).

📋 Technical Details at a Glance

Material: HSS (High-speed steel)
Size range: 4–39 mm
Shank diameter: 10.0 mm
Overall length: 107 mm
Weight: 0.595 pounds (roughly the weight of a small paperback novel)

Stepped Range for the Modern User

The stepped profile spans the hole sizes from 4 mm to 39 mm along a single fluted shaft, so progressive enlargement runs straight through without swapping heads. With a 10.0 mm shank and 107 mm overall length, the cutter reaches panels while remaining stable in most standard chucks.

Save time on repetitive drilling by advancing up steps rather than changing cutters between sizes. Fast progression keeps workshop tasks moving with fewer interruptions.

The Versatile Hole: Why the 4–39mm Range Matters

Stepped cutting enlarges holes progressively, producing consistent edges in thin metals and plastics and reducing the need for pilot drills. The single-shank format locks securely in a standard 10.0 mm chuck for wobble-free rotation.

If you frequently fit cable glands and conduit under 39 mm, the single cutter finishes the job without swapping tools, cutting setup time on routine installations.

Fewer Bit Changes – HSS Material

High-speed steel construction retains hardness when cutting metal, so edges stay sharper through longer runs compared with softer steels. The material sustains higher cutting temperatures encountered in rapid sheet-metal work.

Durable cutting life lowers replacement frequency and keeps workshop downtime minimal, making longer installations more efficient.

✨ The Standout Features of the Bosch Step Drill Bit

Stepped profile – speeds sequential hole sizing without swapping heads
HSS material – retains edge under heat for longer cutting runs
10.0 mm shank – fits common chucks for secure, wobble-free drilling
107 mm overall length – reaches through panels and thin assemblies comfortably

🏆 Our Verdict

Suitable for DIYers and tradespeople who work with sheet metal, plastics and small panels and who need a single solution for multiple hole sizes. The stepped edges give a tactile click as each diameter engages, so users feel progress through each stage rather than guessing. Built for frequent workshop use, the cutter delivers strong long-term value for anyone who drills varied hole sizes regularly.