To drill a hole in wood seems simple enough, but with the variables involved, the wrong bit can crack or chew up the wood. Drill bit composition and the type of hole being drilled all play a part when selecting the right bit for a hole in wood. For the best results, match the drill bit to the project for the best results.
Delicate or Aggressive
Drill bits range from delicate twist bits to aggressive, large cutters. Regardless of the type of bit used, the process of drilling a hole is much the same for all of them.
Drill A Hole
Step 1: The Divot
Use a nail set or other sharp object to create a small divot on the wood to mark the exact location for the hole. This gives you a starting point for your drill bit.
Step 2: Hold It Perpendicular
Hold the drill perpendicular to the wood being drilled. Position the tip of the bit on the divot.
If you have difficulty maintaining a perpendicular position, use a drill guide that attaches to the drill for this purpose.
Step 3: Consistent Pressure
Pull the trigger on the drill and push gently on the drill until the bit engages the wood. Continue apply consistent pressure to the drill, keeping the bit in a perpendicular position as it drills the hole.
Bits by Task
Choosing the correct wood bit for the task at hand alleviates problems with cracking or chewing up the wood. Whether you need to just bore a hole, drill through three studs, create flat-bottomed holes and more, there is a bit designed specifically for the project task.
The twist bit is the most common bit for wood, or anything else. With its familiar shape and spiraling threads that descend to a blunt point, you can use this bit to drill almost any hole in wood smaller than about 1/2 inch -- pilot holes are a perfect example. Hardened twist bits are the best for hardwood. Softwood responds equally well to both.
Some hardened bits have a bright gold color.
Brad point bits are typically for holes 3/8-inch or bigger. Brad points cut cleaner than twist bits. They have a sharp, pencil-shaped pilot bit centered on the shaft. The pilot bit prevents the bit from wandering, keeping it steady as you drill. Use brad bits for dowel holes, or for any hole that requires more precision than a twist bit.
Measure the bit and place tape on it to indicate the stopping point for holes that have a specific depth.
Forstner bits are specialized for the cleanest, most precise holes -- and are the most expensive bits. They don't have spirals; above the pilot bit tip they have a circular cutting knife to keep the bit steady. Use them to drill almost any size hole for fine furniture when the hole requires a flat bottom, such as for the insertion of furniture buttons or plugs.
Spade bits are flat, and look like as small garden spade with a sharp point. As the most difficult bit to use, they are typically for large, rough holes for wires, or any other rough hole in studs or lumber.
All drill bits can bind, but spade bits are more likely to bind and kick than other bits. Use them with caution.
Hole saws, although not typically referred to as drill bits, they attach to your drill to cut the largest holes of any bit -- up to 3 inches or more in diameter. They have a circular saw edge with teeth and a hollow center. Hole saw kits are available with a wide range of interchangeable cutters. Use them for adding holes to doors for door knobs and hardware.
The most common pilot hole, done with a twist bit, is the same size as the shank of the screw. This provides just enough wood for the threads to bite into without splitting the wood. To choose the right sized bit for the screw, use calipers to measure the screw shaft and the bit. If you don't have calipers, drill some test holes on scrap wood and test-fit the screws in the holes.
One of the most challenging techniques is learning to drill accurately at an angle. While there are jigs available for this, you can do the same thing by cutting a piece of wood at the desired angle, clamping it to wood, and drilling through both pieces, using the angled piece to guide the bit.
Bits 1/2-inch or bigger accumulate chips and sawdust while drilling. Periodically stop drilling and pull the bit out of the hole as needed to clear the chips from the hole. Set the drill in reverse, if needed.