Router Bit Speed Guide
Find the recommended RPM for your router bit diameter.
Setting the correct speed (RPM) on your router is crucial for getting a clean cut and for safety. The ideal speed depends primarily on the diameter of the router bit. Larger bits have a much higher rim speed at the same RPM, and running them too fast can cause dangerous vibration, burning, and even cause the bit to fail.
This guide provides generally accepted speed ranges for different bit diameters. The fundamental rule is: **the larger the bit, the slower the speed**. Use this chart to select a safe and effective starting RPM for your routing operations.
- RPM (Revolutions Per Minute): The speed at which the router's motor and the bit are spinning.
- Bit Diameter: The overall cutting diameter of the router bit.
- Rim Speed: The actual speed of the outermost cutting edge of the bit as it moves through the wood. This increases with both RPM and bit diameter.
- Chatter: A form of vibration that occurs when a bit is run at an improper speed or with too heavy a cut, resulting in a poor surface finish.
"The sounds your router makes are a great indicator. If the router is screaming at a high pitch, the speed is likely too high for the bit. If it's bogging down and groaning, you're either taking too deep a cut or your feed rate is too fast. A happy router has a steady, powerful hum." - Fine Woodworking Magazine
"For very large bits, like a panel-raising bit, always start at the absolute lowest speed your router can manage. You can always nudge the speed up slightly if the cut quality is poor, but you can't undo the damage from a bit that shatters because it was spun too fast."
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Always double-check your measurements before cutting.
Account for the kerf (the width of the saw blade) in your calculations.
Consider wood movement (expansion and contraction) in your final dimensions.
Buy 10-15% extra material to account for mistakes and waste.