Machining
Turning surface finish
In short
Theoretical Ra and Rz from feed and nose radius, max feed for a target Ra, N classes. Example with the default values: Theoretical Ra = 0.90 µm.
Calculation
Example calculated with the tool’s default values.
Inputs
- Calculation
- Feed and radius → roughness
- Nose radius rε
- 0.8 mm
- Feed f
- 0.15 mm/rev
Results
- Theoretical Ra
- 0.90 µm
- Theoretical Rz (peak height)
- 3.52 µm
Worked example
Every value in this section belongs to the example, calculated with the tool’s default values.
Other results of the example
- ISO 1302 class
- N7
- Geometric roughness: the real surface is rougher (built-up edge, wear, vibration). Make a trial cut.
Step-by-step calculation
Peak height
Rz = f² / (8 rε) · 1000
0.150² / (8 × 0.80) × 1000 = 3.52 µm
Average roughness
Ra = f² / (18 √3 rε) · 1000
0.90 µm
Max feed by Ra, rε 0,8
| Class | Ra (µm) | max f (mm/rev) |
|---|---|---|
| N4 | 0.200 | 0.071 |
| N5 | 0.400 | 0.100 |
| N6 | 0.800 | 0.141 |
| N7 | 1.600 | 0.200 |
| N8 | 3.200 | 0.283 |
| N9 | 6.300 | 0.396 |
| N10 | 12.500 | 0.558 |
Limits
Indicative results: they replace neither the applicable standards nor the job drawings and instructions. Check the values entered and the result before doing the work.
Sources
Related tools
Other tools · Machining
Machining timeCutting time for turning, facing at constant Vc, drilling and milling, per part and per batch.ISO 286 fitsHole and shaft limits, clearance or interference, any class a to zc up to 500 mm.Threads and tap drillsTap drill for cutting or forming taps, pitch and minor Ø, depth: M, UNC/UNF, G, Rp, Rc, NPT.Tightening torquesTorque and preload of a metric bolt by class and friction (VDI 2230), minimum preload by method.Bolt circleX/Y coordinates of n holes on a circle or arc, hole spacing, full-size marking template and DXF.TapersTaper ratio, angle, compound setting and tailstock offset; Morse, metric and chuck tapers.