A drill bit is effective only as long as it remains sharp. With use, even the best bit loses some of its edge, taking longer to penetrate the surface, or failing to remove the debris from the hole as it dulls. Replacing a dulled drill bit may be quick, but replacement costs mount up. Sharpening your drill bits is an easy, inexpensive alternative to replacement. For a carbide masonry bit, you can successfully sharpen the bit using a bench grinder equipped with a diamond-grinding wheel.
Attach a diamond-grinding wheel to an electric bench grinder. Put on a pair of safety goggles and leather work gloves for safety during the sharpening process.
Turn the bench grinder on and set it to low speed. Grasp the drill bit by the base using a pair of pliers. Place the bit lightly against the rotating diamond-grinding wheel along the cutting edge of the bit near the point. Turn the bit against the wheel, following the cutting edge along the slope of the bit.
Lift the bit from the grinder occasionally and dip it into the bowl of water to cool it off and prevent the bit from warping as you sharpen it. Test the sharpness of the bit with the tip of a finger after cooling it to determine if the last run against the wheel has sharpened it sufficiently. If not, continue the sharpening process.
Clear the grooves of the bit using a small file to remove any loose fragments.
Smaller drill bits may break during the sharpening process due to the thinness of the drill heads.