Auger bits are another option for drilling large holes with a handheld drill, but they are better suited for drilling holes in very thick wood. Auger bits require a drill with a good amount of power, they can be difficult to wrestle, and they can leave a pretty rough hole behind. Hole saws can also get the job done, but they’re slow and removing the plugs from the bit can be a challenge. The best option for drilling of holes up to 1 1/2 inch in diameter when using a handheld drill is a spade bit.
Spade Drill Bits
Also commonly known as paddle bits, spade bits have a wide, flat blade. They are commonly used by tradesmen such as electricians and plumbers for drilling holes in studs in walls for running wiring or pipes (auger bits and hole saws are also used for this), but they also have a place in the woodshop for drilling on fine woodworking projects. The flat, broad blade of a spade bit has a pilot point attached to a 1/4-inch diameter shank that can be chucked into both regularly-chucked drills and quick-chuck impact drivers. Each edge of the flattened portion of the bit is sharpened, and the bottom corners of the sharpened area may have a pointed tip, depending on the style and brand of the bit. As the bit is turned by the drill motor, these two sharpened bottom edges will dig into the wood stock around the center pilot point, shaving wood out of the hole in a corkscrew-like manner. If the cutting edges of the bit are particularly sharp, very long shavings are sometimes produced by the drilling action.
How to Use a Spade Bit
A spade bit is relatively easy to use, but unlike a twist bit, which is somewhat forgiving, it is important for the shank of a spade bit to be perpendicular to the workpiece while drilling. To use a spade bit:
Tips for Using a Spade Bit
One common issue with spade bits is that they tend to splinter and “blow out” the backside of the hole. This blow out can be quite unsightly on a fine woodworking project. There are several methods for drilling clean holes with a spade bit, including clamping a sacrificial board to the backside of the workpiece when drilling; or drilling partway through the workpiece until the pilot point penetrates through the wood, then reversing the board and completing the hole by drilling from the backside. It’s a mistake to drill at a slow speed when using a spade bit. Although a slow speed is necessary as you position the brad-point and start the hole, you should increase the speed as soon as the hole is started. This will produce a cleaner cut with smoother edges. Spade bits must be extremely sharp in order to cut effectively. A machine shop can resharpen your space bits—or you can do it yourself with a mill file or bench grinder. The cutting edges should be honed at an angle of about 10 degrees.
