Even with a steady hand and a sharp eye, it's tough to drill a perfectly centered pilot hole for hardware installation. And if the hole is off-center, the screw won't seat properly. But there's an easy solution. Self-centering bits ($8 to $20) drill a centered pilot hole, resulting in perfectly centered screws. There are several sizes of self-centering bits available. Choose one to match the size of screw you're using.
At times, drills can provide too much power, causing screw heads to snap off or strip, especially with small brass or aluminum screws. Most newer cordless drills are equipped with a clutch, which can eliminate this problem. Set the clutch by twisting the ring near the chuck to the smallest number. Try driving a screw. If the clutch releases (you'll hear a ratcheting noise) before the screw is fully driven, move the setting to a higher number. Choose a setting that drives the screw fully before the clutch releases.
Tip: Using square or star-drive screws and bits reduces the tendency for the bit to slip off the screw head.
Driving screws with a drill can be tricky until you master the technique. The most common mistake beginners make is applying too little pressure. Coupled with bad alignment, this spells trouble. If the bit is skipping out of the screw head and you already know that the bit isn't worn, then improving your technique will help. First, be sure the driver bit is aligned with the screw shank. If the bit's sitting crooked in the screw, it won't engage firmly and will slip. Then, with the bit firmly seated, start the drill slowly (assuming you have a variable-speed drill) while pushing hard against the screw. Apply extra pressure with a hand on the back of the drill body. The combination of correct alignment, pressure and slow speed will ensure that the screw goes in without bit slippage, which can damage the screw head and driver bit.
Magnetic bit holders are so handy that it's surprising they're
not included as a standard accessory with every cordless
drill. Bit holders are readily available wherever cordless
drills are sold ($3 to $8). Some have a sliding sleeve that
keeps your fingers safer by allowing you to drive long screws
without holding the screw shank. Here are a few other
advantages of using a bit holder:
- Driver bits are easier to install and remove.
- The extra length allows better visibility and makes it easier to keep the bit aligned with the screw.
- Long bit holders allow easy access to hard-to-reach areas.
- You can stack two bit holders for an extra-long reach.
Driving screws at an angle (toe-screwing) is a common technique for making right-angle connections. But if you simply angle the screw in the desired direction, it will usually just slip down the board. The key to successfully driving screws at an angle is to use this two-step process to create an angled pilot hole. Choose a drill bit with a diameter equal to the screw shank, not including the threads. First, estimate the entry point based on the length of the screw. Then start the bit at a right angle to the wood at this point (Photo 1). As soon as the drill bit engages the wood, tilt the bit to the desired angle and finish drilling the pilot hole (Photo 2). Now drive the screw into the angled pilot hole to complete the job.
Countersinking bugle head screws so they are flush or slightly recessed leaves a neat appearance. You can drill a pilot hole and a countersink in one step with a combination countersink and drill bit. For straight-shank screws, the less expensive ($3 to $5) straight-bit design works fine. For tapered-shank wood screws, use a countersink fitted with a tapered-shank bit ($10 to $15).
Countersink bits are available with or without stop collars. An adjustable stop collar lets you set the maximum depth of the countersink for more consistent results. Also, you can hide the screw by drilling a deep countersink, called a counterbore, and gluing a plug into the hole. Countersink drill bits are available in sizes to match screw sizes. If you're an avid woodworker, it's worth buying a full set. Otherwise, a No. 7 or No. 8 will cover the most common screw size.
Using worn driver bits is a common mistake. If you're using the right technique and the bit is still skipping in the screw head, it's time to replace the bit. The trick is to have spare bits on hand so you can replace them at the first sign of wear. The next time you're at the home center, buy a 10-pack of No. 2 Phillips bits and you'll always have spares. Don't forget to get a few of the other sizes and shapes too.
Tip: Match the driver bit size to the size of the recess in the screw head. The three common sizes of Phillips bits, smallest to largest, are No. 1, No. 2 and No. 3. Can't tell by looking? Pick the bit with the tightest fit.
Have you ever screwed two boards together but not been able to pull the two pieces tight together? This happens when the screw threads engage in both pieces of wood while there's still a gap between them. One solution is to clamp or nail the boards together before making the permanent screw connection. If you don't want to mess with clamps or nailing, you can drill a clearance hole through the first board to solve the problem. Choose a clearance hole bit that's large enough to allow the screw to spin freely. Even cupped or twisted boards are easily drawn tight with this method.