How to Drill a Hole

Drilling is one of the most common and most useful processes.

Step 1: Measure and Mark

Measure the location of the hole. If possible, mark exactly where the hole needs to be drilled.

Choose the drill size appropriate to the material being drilled and the tool being used. Use common sense. Trying to directly cut a 3/8 inch diameter hole in stainless steel with a hand drill is not the wisest idea. Start with small diameters and work up. If you?re not confident in your common sense, try a handbook such as Machinery's Handbook.

Use this chart to determine what size to drill for a bolt or screw.

Step 2: Center Punch

A center punch makes a small dent in the surface of the material that prevents the drill from wandering when it first contacts the surface.

Step 3: Set Up

Align and clamp the material in place. Clamps are always a good idea. As the drill pierces through the opposite side of the material, it can grab and spin the work piece. If you are holding the material by hand, injury can result. Be especially careful of this when using a hand drill. If the drill bit grabs, the entire tool can be ripped out of your hands.

Step 4: Drill

Put on safety glasses and ear protection as appropriate. Let someone else know you are using power tools, if working alone.

First, ensure that the drill is spinning the right direction and speed. If you wrap your right hand around the drill with your fingers pointing in the direction of rotation, your thumb should be pointing into the material to be drilled.

Alternatively, watch the flutes (the spiral grooves in the drill). When the drill is spinning, they should appear to be moving away from the material. In fact, the flutes? job is to remove cut chips out of the hole.

Again, use common sense or a handbook to determine the proper speed.

Plunge the spinning drill into the material. The drill should be cutting without requiring a tremendous amount of force along its axis. If the drill does not appear to be cutting ensure that the flutes are not clogged. In materials such as aluminum, you need to ?peck? at the material: plunge in to cut, and then pull out to remove chips. Clogging the drill while continuing to apply more and more force into the material is a sure way to break a drill bit.

For metals, cutting fluid can be helpful. Cutting fluid can be oil, water, detergent, or a mixture of those three. It helps to lubricate the sliding contact between the drill and the work piece, flush chips away from the interface, and to cool the drill.

Step 5: Clean Up the Hole

If the edges of the hole are not to your satisfaction, try a deburring tool to cut and smooth around the edge of the hole. Multiple types of deburring tools exist; the picture shows two hand tools with differently shaped cutting bits and a tool used in a drill.

Step 6: Clean Up

Vacuum or sweep up any mess, wipe off any cutting fluid, and put all tools away.