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Surface Finish Converter

Ra (µm)

ISO grade (N)

Ra (µin)

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Rq (µm)

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ISO grade

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Rz ≈ (µm)

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Rq ≈ 1.11·Ra (sinusoidal); Rz is process-dependent (shown as ~4·Ra). µin and N-grade are exact.

A helper, not a substitute for engineering judgment.