by Larry Johnston
Nailing is one of the oldest, simplest and quickest methods for joining two pieces of wood. Rely on nails for indoor and outdoor carpentry and trim work using hardwood, softwood and sheet goods. Here’s some advice on choosing the right nail for your job.
Rely on the Old Standbys
Most hardware stores or lumber yards carry a vast array of nails, but two or three kinds cover most ordinary household jobs. You’ll find many specialty nails for laying flooring, hanging wallboard, installing roofing and siding, or fastening wood to concrete and masonry. Always ask if special nails are recommended for projects or materials you’re unfamiliar with. Otherwise, count on the following as your everyday nails.
Box nail. A box nail looks like everyone’s idea of a nail, with a flat head and a point. Its big brother, the common nail, is a little larger in diameter. The thinner box nail is easier to drive and less likely to split wood. To make up for the reduced holding power of a thinner nail, many box nails are coated with resin (tagged as "cement-coated" or "cc") or vinyl ("vinyl-coated") for added grip. If there’s any such thing as a standard nail, it’s probably the cc box nail. Buy galvanized box nails for fences and other exterior projects.
Finishing nail. You can sink the small head of a finishing nail below the surface to hide it, making it the preferred fastener for cabinetry and interior trim work. Finishing nails are slightly thinner than same-length box nails. Casing nails also have a small head suitable for sinking, but they’re a little fatter — the same diameter as same-size box nails — and available with galvanized coating for exterior trim.
Brads or wire nails. When even the smallest nail is too big, turn to wire nails (flat heads) or brads (heads like finishing nails). They're usually packaged in boxes or tubes of a few ounces, sized by length and wire gauge, such as 1/2 inch x 17. The larger the wire-gauge number, the smaller the diameter, so a 1/2 inch x 17 wire nail is fatter than a 1/2 inch x 19 one.
Be Penny Wise about Nail Size
Nail sizes are expressed in pennies, abbreviated like the British money penny by the letter "d." Penny size (such as 6 penny or 6d) now refers solely to nail length, but folklore holds that it once referred to the cost of 100 nails (sixpence for 100 6d nails, for example) or perhaps the price of a given weight of nails.
Nail diameter is proportional to length, as shown in the chart below. Nails are priced by the pound. You’ll usually find them packaged in boxes, although some dealers may sell them out of kegs. The chart shows approximately how many nails you get per pound.
Drive Nails like a Pro
Driving a nail isn’t that hard, but the following tips can help you get it right:
Choose the right nail type. If you’re building a wall, use common or box nails for the framing but change to special drywall nails or paneling nails when you cover the wall. Fasten the trim with finishing nails.
Buy galvanized, aluminum, stainless steel or other rustproof nails for outdoor work; they’ll last longer and stop corrosion streaks from marring your work. Pressure-treated lumber corrodes nails, so if you’re building a deck or fence with pressure-treated lumber, ask for coated or rustproof nails suited to the material.
Choose the right length. Pick a nail of a length at least three times the thickness of the material you’re nailing through or one that’s long enough to go through the first piece and at least half to two-thirds of the way into the piece you’re attaching it to. A nail should penetrate at least 1/2 inch into wood to hold well. Always nail through the thinner piece into the thicker one.
When nailing to a drywall-covered wall (installing a shelf cleat, for example), increase nail length by 1/2 inch to go through the drywall, which offers no nail-holding power. Attach that 3/4-inch shelf cleat, for instance, with nails at least 2-3/4-inch long (3/4 x 3-1/2 inch). The best choice: 10d nails. Drive them into the studs, of course.
Use the right hammer the right way. A 16-ounce hammer with a smooth face is great for finish work. But to drive a lot of 16d nails for a fence or wall framing, get a 20-ounce framing hammer with a waffle face for easier work. Go with a lighter hammer of about 8 ounces for small nails, wire nails and brads.
When driving a nail, strike the head squarely with the center of the hammer head's face. You’ll bend the nail if you hit it at an angle or with a glancing blow. Practice swinging the hammer from your elbow rather than your wrist to ensure a square hit.
Drill pilot holes. Pre-drill hardwood moldings with pilot holes to minimize splitting and make nail-driving easier. If you’re attaching the moldings to hardwood paneling, drill pilot holes in that too. You don’t need pilot holes in softwood framing. See pilot-hole specs below.
You Don’t Have to Split Wood
Driving a nail into wood pushes the fibers apart, often causing the wood to split. Splitting is more likely in hardwoods and in very dry or old wood. Try these tricks to minimize splitting: Use a thinner nail. Box nails are less likely to split wood than heftier common nails. Maintain holding power with cc or vinyl-coated box nails.
Blunt the nail tip. Stand the nail it on its head and rap the point once with your hammer before you drive it. The blunted tip tears some of the fibers as it enters the wood, reducing the possibility of splitting.
Drill a pilot hole. A pilot hole provides the surest defense against splitting. Make it about 85 percent of the nail's diameter and around half to two-thirds its length. The chart shows pilot hole sizes for some standard nails.
Stay away from the end. Nailing too close to the end of a board almost always splits it. Nail as far from the end as possible — at least one board thickness — taking both parts of the joint into account. Or drill pilot holes.
Watch the grain. Instead of placing nails evenly in an attractive pattern, drive them through different grain lines. Don’t nail near the edge into a grain line that runs off the board's edge.
Don’t get your nail in a knot. Driving a nail — or trying to drive one — into a knot or the hard area adjacent to one will almost certainly split the wood.
Writer and do-it-yourselfer Larry Johnston hasn’t hammered his thumb in years, but he still occasionally bends a nail.