This router cutter reference helps you pick a safe, effective spindle speed for a given cutter diameter and material, and acts as a quick guide to common bit profiles. Running a bit at the wrong speed burns the work, dulls the cutter, and can be dangerous — especially with large-diameter bits.
Big bits, slower speeds
The critical figure is rim speed — how fast the cutting edge travels — which rises with both spindle RPM and cutter diameter. A large panel-raising bit has a much faster rim speed than a small straight bit at the same RPM, so it must be run slower to keep the edge speed in a safe, effective range. The reference suggests a maximum RPM band for each cutter size, helping you avoid the burning, chatter, and risk that come from overspeeding a big cutter.
Feed rate works with speed: too slow and the bit dwells and burns (especially in cherry and maple); too fast and it tears out or stalls. Taking the cut in several shallow passes rather than one deep one keeps the load on the cutter reasonable and the finish clean.
Choosing and using bits
Match the bit to the job — straight bits for grooves and dados, flush-trim and pattern bits for templates, round-overs and chamfers for edges, and profile bits for mouldings. Keep cutters clean and sharp, use the largest shank your router accepts for stability, and always confirm a bit's own rated maximum speed, which overrides any general guideline.
Choosing a speed for a large 90 mm panel-raising bit.
- Large-diameter bits have high rim speed, so they need low RPM.
- Panel-raising bits of this size are typically run near the router's lowest setting.
- Confirm against the bit's own rated maximum and take shallow passes.
Run the big panel-raiser at the router's lowest speed band and feed steadily in light passes.
