Avoiding Damage to Table-Mounted Routers

I just read a letter in one of the woodworking magazines about how to keep debris from falling into the motor in a table-mounted router. The answer sounded kind of weird, and I thought I'd see if you guys have any opinions on the subject.

Opinionated? Us? Come now! Now that you mention it, though, we do happen to have an idea or two on the subject. Upon close observation you'll note that the design of your router motor incorporates a fan, usually just within the bottom of the housing, that draws cooling air over the windings. Fortunately, the engineers responsible for router design figured out some time back that the airflow should come in the top of the motor and be directed out the bottom, so as to avoid sucking up huge wads of debris every time you put a hand-held router to work. Now, it's true that in a router table the router is upside down — but it is hardly defenseless. When it's running, there's a powerful blast of cooling air coming out of the grating just below the collet, and it is virtually impossible for shavings and dust to make their way through that blast, past the turbine blades and into the motor. It is our conclusion, therefore, that the best way to protect your table-mounted router is to turn it on. Debris will fall into the motor only if you put it there deliberately by sweeping the mess on your table surface through the bit opening after the router is shut off. So don't! Vacuum the table or sweep the trash off onto the floor where it belongs, and you'll do all right.