Set Up Surface Finish
Choose metric or imperial, then enter radial step-over and cutter diameter in the same unit system.
Surface Finish Calculator
Estimate theoretical milling cusp height from radial step-over and cutter diameter.
Metrik MFG / Surface FinishREADY
Surface Finish Calculator
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Surface Finish Calculator
Advanced Engineering
PRACTICAL CONTEXT
Using the result in real shop work
This calculator estimates the geometric cusp height left by a circular cutter during a milling pass. Actual surface finish can differ because of runout, vibration, tool wear, toolpath details, machine condition, and material behavior.
Where This Result Helps
Use it for early process checks and for comparing how radial step-over and cutter diameter affect the geometric scallop height.
What Can Distort the Result
Treating the result as measured Ra/Rz, mixing units, using a step-over larger than the cutter diameter, or ignoring runout and toolpath geometry.
ENGINEERING METHOD
How the surface finish calculation works.
FORMULAFor circular cutter geometry, h = R − √(R² − (s/2)²), where R = D/2 and s is radial step-over. This is a theoretical cusp-height estimate, not a measured Ra or Rz value.
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