A bench grinder can help ensure that your drill bits are sharp enough for any job. It should only be used, however, if the bit has become very dull. Regular maintenance of your drill bits will cut down on how often you need to use the grinder.
Step One: Preparation
Before you begin you need to take safety precautions. Sharpening your drill bit will cause metal to fly through the air. You need to protect your eyes with a pair of goggles. The leather gloves will also aid in protecting your hands. If possible, use a vise or a sharpening jig to hold your drill bit. these tools make it easier to operate the bench grinder and help ensure that the bit is always held at the correct angle for the job. If you can not, use a pair of pliers. It is best to keep your hands away from the grinder.
Step Two: Sharpening and Cooling
In order to correctly sharpen the drill bit the grinder will need to be set at t a slow speed. Place the bit against the base of the wheel so that the sloped side touches the cutter. This should be near a 60 degree angle for most bits. Do not let the tip of the bit touch the grinder. Slowly rotate the bit in a clockwise direction. Every few seconds you should remove the bit and place it in a glass of water. This, in addition to the slow wheel, will prevent the bit from over heating.
Step Three: Testing
Every so often you need to check the sharpness of the drill bit. Do this by removing a glove and touching the bit with your finger. If you find it sharp you will not need to continue using the grinder. You will also need to check the angle of the drill bit. Use the protractor to ensure that the bit still has a 60 degree angle. Check this periodically throughout the process to prevent any mistakes.
Step Four: Finishing
Once the bit is fairly sharp you need to use a metal file to finish the job. This will prevent you from over-sharpening the bit. Place the bit in a vise or clamp and use a metal file to sharpen it. Keep the file at an angle. Work slowly and methodically.
Step Five: Maintenance
If you treat your bits correctly, you can avoid the use of a bench grinder to sharpen them. As the bits begin to dull, sharpen them with a metal file. While you may have to do this more frequently, you will save yourself the trouble of your bit becoming to dull to use. A metal file is also safer to use than a bench grinder. In addition to regularly sharpening the drill bits you should be sure to store them correctly, in the original casing.