- Tape measure
- Bench grinder
- Wood block, 2-by-2-by-12 inches
- Miter saw
Make an accurate drill bit sharpener using a bench grinder and a block of wood to regulate the angle. The problem with hand sharpening bits is the tendency to change or alter the angle of the bit. If you can establish and maintain the correct angle, sharpening bits becomes less complicated. Cut a small block with the desired angle, and place it directly in front of the wheel to use as a guide for sharpening. With the sharpening angle in place, bits can be sharpened correctly every time. Many common bits have an angle of 15 degrees. Start there.
Measure from the farthest outside perimeter point of the grinding wheel to the tabletop with a tape measure. Measure up from one corner on the 2-inch block. Use the measurement to make a mark on the block.
Set a miter saw at 15 degrees. Place the block against the miter saw fence with the mark against the fence. Cut down through the block. The mark should be at the long point of the cut.
Stand the block on its bottom with the angle facing you. The long point of the cut should be touching the center of the wheel; it doesn't have to be perfect.
Lay a drill bit on the angle with the tip of the drill bit facing the grinding wheel. Slide the bit up to the wheel. Look straight down at the point where the bit touches the wheel. If the angles do not match, place the block on the miter saw. Change the angle slightly on the wheel, make another cut and check it. Repeat if needed until the drill bit angle matches the downward angle of the wheel.
Turn on the grinder. Ease the bit into the wheel gently to sharpen the bit. Twist the drill bit in circles with your fingers, maintaining the angle on the block sharpener. Check the bit for sharpness and continue if needed.
Practice hand sharpening like this. You will get good at it. There are all different profiles of bits with different angles; the measurements here are examples. Cut blocks at any angle, or reposition the block for best results on differing bits. Make several of them for different bits.
Wear safety glasses when working with grinders.