This surface finish calculator estimates the roughness average (Ra) based on feed per revolution and tool nose radius.
Surface finish is strongly influenced by feed rate and tool geometry.
Formula:
Ra ≈ (Feed per revolution²) / (32 × Tool Nose Radius)
Lower feed rates and larger tool nose radius produce smoother finishes.
Example:
If feed = 0.010 in/rev and nose radius = 0.032 in:
Ra ≈ (0.010²) / (32 × 0.032) ≈ 98 microinches.
When to use this calculator:
Use this calculator to estimate surface roughness based on feed rate and tool geometry.
Machining tip:
Reducing feed rate or increasing tool nose radius can significantly improve surface finish.