A grinder is a handy and easy-to-use tool. It's also faster and more dangerous than many other workshop tools. Unlike electric drills that turn 700-1200 rpm, grinder wheels spin at more than 10,000 rpm. So, always wear a face mask and gloves, and keep all onlookers away. To change wheels, unplug the grinder first. Then test-run any wheel change -- old and new alike -- to ensure it doesn't come apart or spin off. Also, always use the extra handle, and debris guard, if possible, and maintain a firm grip with both hands. Position work so that sparks and debris fly downward, and so that the wheel spins away from and, not into, or toward your work. Wheels, especially wire ones, can catch an edge and turn your work into a deadly missile, or cause the grinder to kick back. Your best -- and safest -- bet is to securely clamp your work down before you start. And that's the On The House Tip for today.