Stepover (Scallop Height) Calculator

MILLING

Find the maximum stepover for a ball nose tool that keeps the scallop (cusp) height under a target finish tolerance.

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Max Stepover (in)

Stepover = 2 x sqrt(R^2 – (R – h)^2), where R = D/2 and h = target scallop height.

How it works

A ball nose tool leaves a curved cusp between adjacent passes. The stepover that keeps that cusp below a target height is set by the tool radius and the height itself, geometry only, independent of feed or speed.

FAQ

What scallop height should I target? 0.0005 in (about 0.0127 mm) is a common fine-finish target; rough passes can use much larger values.

Related Guides

CNC Calculators · Ball Nose Feed Calculator

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The calculators and tools on Formula Factory are provided for general guidance and informational purposes only. Results are estimates based on standard formulas and the values you enter — they do not constitute professional engineering, electrical, or architectural advice. Always verify calculations with a qualified professional before making decisions for any safety-critical, code-compliance, or commercial application. Formula Factory makes no representations or warranties as to the accuracy or completeness of any result, and accepts no liability for errors, omissions, or any outcomes arising from reliance on this information.