Recommended Rake Angles for Milling Cutters
The radial rake angle of an arbor hole style milling cutter or slitting saw is the angle between the tooth face and a radial line passing through the cutting edge in a plane perpendicular to the cutter axis that the tooth sits at relative to the center of a milling cutter. It can be positive or negative. This angle is important because different materials machine better at different rake angles all other things being equal.
Below is a diagram showing how the rake angle of a milling cutter is measured.
Below are some general recommendations for rake angles when machining certain materials:
CLASS OF MATERIALS | MATERIAL EXAMPLES | RECOMMENDED RADIAL RAKE ANGLE |
NON-FERROUS (SOFT) | ALUMINUM ALLOY – WROUGHT | 10° |
MAGNESIUM ALLOY | ||
LEAD ALLOY | ||
NON-METAL AND PLASTIC | ||
ZINC ALLOY – DIE CAST | ||
NON-FERROUS (HARD) | ALUMINUM BRONZE | 5 to 10° |
BRASS ALLOY – LEADED AND FREE CUTTING | ||
NICKEL SILVER | ||
COPPER ALLOY – TOUGH | ||
CAST IRON | DUCTILE CAST IRON – AUSTENITIC | 3° |
DUCTILE CAST IRON – FERRITIC | ||
DUCTILE CAST IRON – MARTENSITIC | ||
GRAY – PEARLITIC | ||
GRAY – FERRITIC | ||
MALLEABLE CAST IRON – MARTENSITIC | ||
LOW CARBON STEELS | LOW AND MEDIUM CARBON STEEL – FREE MACHINING | 0° to 3° |
LOW AND MEDIUM CARBON STEEL – WROUGHT | ||
MEDIUM STRENGTH STEELS | LOW AND MEDIUM CARBON ALLOY STEEL – FREE MACHINING | 0° to 3° |
LOW AND MEDIUM CARBON ALLOY STEEL | ||
STAINLESS STEEL – 400 SERIES | 3° to 5° | |
STAINLESS STEEL – 400 SERIES FREE MACHINING | ||
HIGH STRENGTH STEELS | HIGH STRENGTH STEEL – WROUGHT & TOOL STEEL | 0° to 3° |
HIGH TEMP ALLOYS | HIGH TEMP ALLOYS – NICKEL & IRON BASE ALLOY | 5° |
STAINLESS STEEL – 300 SERIES | ||
STAINLESS STEEL – PH SERIES | ||
TITANIUM ALLOY |
Every application is unique so it is best to check with the manufacturer of your cutting tool to help determine the appropriate cutter (and rake angle) for your application.
If you have any questions about rake angles (or any other cutting tool questions) feel free to leave us a comment here on our blog or fill out the form on Super Tool’s Contact Us Page.
Bryan Enander
Super Tool, Inc
941-751-9677