KEVOS® MAKEOS · Manufacturing
Speeds and Feeds in Inch Units
What spindle speed and feed rate follow from this SFM and chip load?
Spindle speed from surface feet per minute and diameter, and feed rate from inches per tooth (or per revolution), with metric equivalents.
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How this tool works
Inputs, units and where to find them
| Input | Unit | Typical source |
|---|---|---|
| Surface speed | ft/min | Recommended surface feet per minute for the tool and material. |
| Cutter or work diameter | in | Effective cutting diameter in inches. |
| Number of teeth (1 for turning or drilling per rev) | teeth | Flutes or inserts on the cutter; 1 when the feed is per revolution. |
| Feed per tooth (or per rev) | in | Chip load per tooth (or feed per revolution for turning and drilling). |
Method and formulas
- RPM = 12 × SFM ÷ (π D) ≈ 3.82 × SFM ÷ D.
- IPM = RPM × teeth × IPT.
- Metric: m/min = SFM × 0.3048; mm/min = IPM × 25.4.
- Example: 400 SFM on a 0.5 in cutter is 3,055.8 rpm; at 0.002 in/tooth with 4 teeth the feed is 24.446 in/min.
Limitations
- Supplier recommendations govern; check machine speed and power limits.
- Example values are illustrations. Replace them with values for your actual task.
Typical uses
- Convert supplier SFM and IPT data to machine settings
- Check inch programs
- Work with US tooling catalogues
Who it is for
- Machinists
- CNC programmers
- Manufacturing engineers
What you get
- Spindle speed
- Feed rate
- Metric equivalents
Interpreting the result
- Round the RPM to the nearest available speed and recompute the feed.
References
- Machinery’s Handbook, 29th edition (Industrial Press, 2012), printed pp. 1013–1017. Topic reference; no source tables or recommended settings are reproduced.
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