[donut]

Be aware, your discs "should" have a speed rating on them, personally I prefer a higher speed rating than the tool your using. IIRC, this goes for any grinding "rocks"

Like with a skillsaw blade, you only want to cut through (shallow), not plunge the wheel to full depth. Don't throw your extra wheels into the bottom of your toolbox, toss wrenches on them, and not expect them to be damaged.