Can I grind a standard drill into a step drill?

Yes, on a universal tool and cutter grinder. Use a diamond wheel for carbide and avoid overheating during grinding. The step transitions must be concentric within 0.002 inches TIR. For critical step dimensions, use a CNC tool grinder for repeatable geometry.

What is the maximum number of steps for a single tool?

Practical limit is 3–4 steps for manual tool grinding and 5–7 steps for CNC-ground tools. Beyond this, chip evacuation becomes ineffective, and the tool's cross-sectional rigidity is compromised. For holes requiring more than 4 steps, consider using a step reamer instead.

How do I prevent step drill chattering?

Chatter at step transitions is caused by interrupted cut forces. Reduce feed rate by 30% during step transitions. Ensure the toolholder has minimal runout (under 0.0005 inches TIR). Use a stub-length step drill where possible — a shorter tool is exponentially more rigid. ⚡ Calculated for Carbide-Tooling.com High-Performance Series. View Catalog →

Home › Tools › Step Drill Design Calculator

📐 Design Guide

Step Drill Design Calculator

Design step drills for counterbores and stepped holes. Calculate safe step transitions and chip clearance.

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📐 Step Drill Design

Safe step depth is approximately 0.5-1× the step diameter per step.

📐 Small Diameter (mm)

📐 Large Diameter (mm)

📏 Total Depth (mm)

🔧 Material

Max Step Depth

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Chamfer Width

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Min Pilot Depth

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Chip Clearance

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Step Drill Design Calculator

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