Take precautions when sharpening drill bits to prevent them from overheating. Ensure the bench grinder or belt sander is properly equipped with a water reservoir beneath the grinding wheel to keep it cool.
Use a sharpening stone and plenty of lubricants (or water) while sharpening, which will help to reduce friction and further relieve heat build-up.
Avoid using too much pressure. This can cause excessive heating in the bit, so always use light and steady pressure when sharpening it.