Estimate theoretical surface roughness from feed and tool nose radius. Use it to compare finishing parameters before turning, boring, or milling a critical surface.
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Request a Proposal →The calculated value is ideal geometry. Actual measured roughness can be worse if chatter, built-up edge, or tool wear is present.
Feed, nose radius, tool sharpness, vibration, material behavior, coolant, machine rigidity, and tool wear all affect the measured finish.
Reduce feed, increase nose radius where geometry allows, improve rigidity, use a sharp finishing edge, and remove chatter.
No. It is a theoretical estimate. Real surface roughness must be measured with proper inspection equipment.
Use this calculator to estimate theoretical Ra and compare finishing feeds before turning, boring, or milling a critical surface.
Continue with closely related tools from the machining calculator library.
Use the calculator freely. If the result points to a tooling or process problem, we can source the exact carbide tooling you need from vetted factories in China. Compare factory-direct pricing.
Before you commit to a spec, it helps to know what the market pays for it. These are real, publicly listed factory prices — not a quotation, and not a guess.
We source the tool families below direct from vetted Chinese factories, matched to the material and tolerance you just worked out. Every batch ships with its material certificate and dimensional record.
SPECIFYING AN Ra VALUE? Surface finish is the spec where cheap and good tooling look identical on paper and different in the cut. See how we verify finish capability at the factory.
Surface finish is bought with the wiper geometry and the grade, not with the speed alone. Send the Ra you need, the material and the operation.