When drilling fragile, very thin or brittle materials, a pilot bit can sometimes crack or split the surface. It becomes necessary to drill a large diameter hole without a pilot bit. Drilling freehand with a hole saw is impossible. But with a guide plate, it's easy. A guide plate is a sleeve into which the hole saw fits to stabilise the saw.
Unscrew the collet from the hole saw and take out the bit. Remove the drill bit from the collet, using a 1/16-inch hex-head wrench. Screw the collet back onto the hole saw.
Clamp the guide plate onto the surface of the object where you want to drill. For material that you can't get a clamp on, hold it securely with your hand.
Insert the hole saw minus the pilot bit into the drill.
Insert the hole saw into the guide plate. Turn it on and begin drilling slowly, letting the teeth form the perimeter of the hole. Lean into the drill with your shoulder until you have drilled about 1/2 inch deep. Stop drilling.
Hold the drill at arm's length but keep it in the hole as you step back and check your vertical alignment. Make adjustments if necessary. Continue drilling.
Pull the hole saw out of the hole if it starts to bind or burn. Blow the dust out of the hole. Continue drilling. If you are drilling completely through an object and you have access to the back of it, when you are within about 1/2 inch of penetrating the other side of the wood, hold a piece of scrap wood behind the wood being drilled. Hold it tight and flat against the back where the hole saw will emerge. Drill through the wood, letting the scrap piece stop the hole saw.
- You can buy guide plates or make them with a drill press for every size of hole saw that you use. Insert hole saws, with pilot bits, one at a time into the drill press. Drill holes of different sizes through a piece of wood approximately 3/4-by-4-by-8 inches.
- Always be prepared for kickback when drilling with a hole saw. Keep your arms and wrists braced at all times.