Definition
Grinding uses an abrasive wheel to remove a small amount of material and achieve a very fine surface finish or tight flatness or roundness.
What it means for the calculation
Often the last step to reach a roughness or flatness requirement that milling or turning alone cannot reliably achieve, for example on sealing faces in semiconductor equipment.
Where it appears on the drawing
Implied by a tight surface-finish symbol or a tight flatness or cylindricity callout that a standard milling or turning pass cannot reliably hit.
Common mistakes
Specifying a very fine finish without realizing it adds a separate operation and cost. Also assuming grinding fixes a form error like taper on its own without checking the root cause.
Often the last step to reach a roughness or flatness requirement that milling or turning alone cannot reliably achieve, for example on sealing faces in semiconductor equipment.
See how Blake reviews a partFrequently asked questions
Why is grinding usually a separate step, not part of milling or turning?
Because it uses a different tool and machine, aimed at removing a very small amount of material precisely.
Does grinding fix any accuracy problem?
No, it can improve finish and tight form, but it cannot correct a fundamentally wrong feature location.
When does a drawing usually require grinding?
When a surface-finish or flatness/cylindricity value is tighter than milling or turning alone can reliably achieve.