Cast iron
Cast iron Speeds and Feeds
Brittle and produces short chips. Avoid coolant on gray cast iron for interrupted cuts.
Milling Cast iron
Power is a rough estimate using the material unit power factor. Verify against your spindle rating.
Spindle speed
- RPM
Feed rate
- IPM
Material removal rate
- in3/min
Approx. spindle power
- HP
Editorial estimate only
These are conservative starting points, not a guarantee. Verify against manufacturer tooling data and your machine manual. Confirm spindle power, workholding and coolant before cutting.
Drilling Cast iron
Spindle speed
- RPM
Feed rate
- IPM
Editorial estimate only
These are conservative starting points, not a guarantee. Verify against manufacturer tooling data and your machine manual. Confirm spindle power, workholding and coolant before cutting.
Cast iron reference values
Editorial estimates for illustration. Start on the low end and adjust to your tooling and machine.
| Operation | Surface speed | Chip load / feed | Unit power (approx) |
|---|---|---|---|
| Milling | 60-120 SFM (18-37 m/min) | 0.001-0.002 in/tooth (0.025-0.051 mm/tooth) | 0.8 HP per in3/min |
| Drilling | 60-100 SFM (18-30 m/min) | 0.003-0.006 in/rev (0.076-0.152 mm/rev) |
Frequently asked questions
What surface speed should I use for Cast iron?
A conservative milling range is 60-120 SFM (18-37 m/min). Coated carbide can run higher; HSS should stay on the low end.
What chip load should I use for Cast iron?
A typical milling chip load is 0.001-0.002 in/tooth (0.025-0.051 mm/tooth). Use the low end for small or fragile cutters and increase only as your setup allows.
Are these values safe to cut with?
These are starting points, not a guarantee. Always verify against your tooling manufacturer data and machine manual, and confirm spindle power, workholding and coolant before cutting.