6 Essential Drill Bits
Woodworkers have come a long way since the days of the bit and brace. Though we may romanticize those times, limited bit options meant craftsmen often settled for holes that were “good enough.” Today, we can choose from specialized bits, many of which create clean, tear-out-free holes, and others that drill specially shaped holes, something that eluded woodworkers of long ago. These bits fit most of the needs of today’s woodworker.
• Brad-point bits. Guided by a centerpoint, these bits resist wandering. Sharp corners, or spurs [Photo A, below], cut cleanly across the grain, eliminating tear-out and producing holes with clean sidewalls. The deep flutes clear chips quickly. You’ll find these bits in diameters ranging from 1⁄8 " to 1".
The larger the bit, the slower the drill-press speed to prevent overheating the bit. Secure the workpiece against a fence or to the table with clamps.
• Forstner bits. For drilling flat-bottomed holes, overlapping holes to create mortises, or partial holes that extend off the edge of a board, use a Forstner bit. Here again, a center spur ensures an accurate start. The sharpened rim produces clean edges, and angled cutters between the spur and rim plane away waste. Because of the large shavings they create, occasionally retract the bit from the hole while drilling to clear chips and reduce the chance of the bit binding or overheating. These bits may have a smooth rim or a saw-tooth rim [Photo below] and come in diameters from 3⁄16 " to 4". Use bits larger than 3⁄8 " in a drill press to control the rotational torque created by the large cutting surface.
• Taper and countersinks. Ideal for drilling pilot holes for screws, they create a hole for the screw shank as well as a recess that allows the screwhead to sit flush with the wood surface, or be counterbored as needed. Adjust the collar around the bit up or down to match the screw length. Find bits sized to match #4–#12 screws.
• Self- centering bits. The spring-loaded nose, sized to fit the screw hole on a hinge leaf, retracts when drilling, centering the pilot hole. That ensures hinge screws seat fully in the countersink in the leaf, and hinges end up where intended. Bits sized for #4, #6, and #8 screws prove most useful.
• Twist bits. Wander into any woodshop and you’ll find common twist drill bits, the utility players of drilling. Available at hardware stores, this versatile bit has a 118° tip [Photo C, below] that drills into wood, plastic, and metal. Because the cut begins at the center of the tip and moves to the outside edge, wood fibers on the periphery of a hole suffer tear-out.
• Spade bits. Though generally not used in furnituremaking, these bits make short work of drilling holes in construction-grade wood projects. Again, a centerpoint guides the bit, and outside spurs reduce tear-out on the edge of the hole. Find these in diameters from 1⁄4 " to 11⁄2 ". Back up the material when drilling a through-hole to reduce blow-out as the bit exits the board.
So there’s the drill. Add these bits to your workshop to open up a “hole” world full of boring possibilities.