Use the tables below as a reference layer for the calculators. The formulas define the arithmetic; the material and tool manufacturer define the appropriate starting cutting data.
Formula chart
Metric spindle speed
RPM = (1000 × Vc) ÷ (π × D)Vc in m/min; D in mm.Imperial spindle speed
RPM = (12 × SFM) ÷ (π × D)SFM in ft/min; D in inches.Milling feed
Feed = RPM × z × fzz = flutes; fz = feed/tooth.Feed per revolution
f/rev = Feed ÷ RPMUseful for turning and drilling.Milling MRR
MRR = Feed × WOC × DOCFor a simplified rectangular engagement model.Cutting time
Time = Distance ÷ FeedConstant-feed estimate.Unit conversion chart
| Quantity | Metric | Imperial | Relationship |
|---|---|---|---|
| Cutting speed | m/min | SFM | 1 m/min ≈ 3.28084 SFM |
| Diameter | mm | in | 1 in = 25.4 mm |
| Feed | mm/min | in/min | 1 in/min = 25.4 mm/min |
| Feed/rev | mm/rev | in/rev | 1 in/rev = 25.4 mm/rev |
Starting-reference chart
These are broad reference families, not universal production settings. Use exact manufacturer data for the selected tool, grade, geometry and operation.
| Material family | What changes the cutting range | Primary concern |
|---|---|---|
| Aluminum | Alloy, temper, tool geometry, coating | Chip evacuation / edge buildup |
| Mild steel | Grade, hardness, tool material | Rigidity / tool wear |
| Stainless | Grade, hardness, work hardening | Heat / rubbing |
| Titanium | Alloy, engagement, tool geometry | Heat / load |
| Brass | Alloy and geometry | Chip control / finish |
| Cast iron | Grade, tool material, coating | Abrasive wear / dust |
| Hardened steel | Hardness, cutter and coating | Tool life / thermal load |
How to use a chart
- Match the exact material and condition.
- Match the tool material and geometry.
- Match the operation and engagement.
- Confirm the units and definition of each number.
- Transfer the source values into the relevant calculator.
- Check the result against machine limits and the physical setup.