Let me drop this timely safety advice from BoingBoing (How to stay safe in the workshop - Boing Boing) :
Safety glasses are really all you need for most projects, they offer good protection from flying debris and light to moderate dust. Wear them when there’s any chance that something unpleasant could hit you in the eye. Even a tiny grinding disk on a low power rotary tool can shatter and send shards on a high-velocity mission to cause harm. (Ask me how I know.) Your blink reflex is not nearly fast enough to protect you.
That could go double for cheap knock of rotary tools:
