I've started fires with 3 1/2 HP routers and 3/4" carbide bits turning at 22k. The culprit is the heat that builds up in the compresed wood fibers and transfers to all that getting-denser-by-the-minute dust. For dadoes use an upshear bit or clear the cut (back up the bit)every few inches. Rabbets should be ok. It;s when the dust has nowhere to go trouble starts.