The experienced carpenter examines several factors when choosing a wood boring tool: the type of wood being drilled, the size of the hole and the finished appearance of the hole. Hardwoods require different tools than softwoods, and certain wood boring tools create smoother cuts than others. With an understanding of the applications of various wood boring tools, you can choose the right type for your woodworking project.
The twist bit is the most basic wood boring tool, and it attaches to both handheld power drills and drill press machines. The primary component of the twist bit is a cylindrical rod. One end of the rod is flat, and the other end of the rod is tapered, like a cone, to a point. Sharp-edged channels coil from the rod's base to its tip. The channels' sharp edges bore into wood, and their spiral layout pushes waste from the hole. Twist bits perform best in soft woods, create relatively clean cuts and generally do not exceed 3/4 inch in diameter.
The paddle bit, also called a "spade" bit, bores rough holes through soft woods, particularly construction framing lumber. As its name suggests, the cutting head of a paddle bit shares its shape with a canoe paddle or garden spade. However, the paddle bit's cutting head is almost completely flat and, unlike a spade or paddle, a sharp point protrudes from the centre and each side of its sharpened cutting edge. Paddle bits mount to both handheld power drill and drill presses and remove material chip by chip. As a result, the paddle bit usually leaves splintered edges around its hole. On the other hand, paddle bits are among the least expensive wood boring tools and perfectly suitable for boring access holes through rough carpentry framing.
Similar to the twist bit, a sharp-edged, fluted channel spirals around the shank of the auger. However, the augers shank is generally thicker and its flute deeper than the twist bit. Additionally, a threaded, screwlike tip protrudes from the end of the auger. The screwlike tip screws into the wood and pulls the shank of the auger forward. As the edges of the fluted channel bore through the wood, their spiral design pushes wood chips out of the hole. Auger drills are long; typically 12 inches to 2 feet. Because of its length, carpenters and construction professionals use the auger to drill through thick beams and boards. The auger mounts to both handheld power drills and drill press machines and creates a reasonably smooth-edged cut.