A roundup of the various types of screws, bolts, and nails, and the proper application for each
Lag Bolts & Screw Eyes
Hollow Wall Fasteners
A variety of nails, screws, bolts, and other fasteners are integral to the construction of houses. Most of these are sold at hardware stores, lumberyards, and home improvement centers; some of the more specialized items are sold at builder’s supply outlets.
Throughout HomeTips, you will see many different types of hardware, some very innovative. In this article, you can gain an understanding of fundamental hardware and fasteners so you can be an informed buyer next time you visit your local hardware store.
Though they are more expensive than nails, screws offer several advantages for certain types of construction. Screws are stronger than nails, they do not pop out as readily as nails do, and, in most applications, they are easily removed. In addition, their coating is less likely to be damaged during installation, and there are no worries about hammer dents.
Most screws are made of zinc-plated steel, but they also can be made for special purposes from softer metals such as brass and aluminum. Screws also may have finishes that are plain, blued, dipped, brass-plated, or chrome-plated.
Conventional wood screws are measured by length, from 1/4 inch to 6 inches, and the size or gauge of the unthreaded shank, from gauges 2 to 24. They are classified by type of head, each requiring a specific screwdriver tip: standard, Phillips, or square-drive. Before you can drive a screw, you must drill a pilot hole.
Drywall screws (also called multipurpose screws) have a black coating that is not rust-proof; deck screws are galvanized for corrosion-resistance, making them suitable for areas exposed to moisture. Both drywall and deck screws have sharp points, coarse threads along their thin shanks (deck screws have a coarser thread than drywall screws), and Phillips-type heads; they’re designed to be driven with a Phillips screwdriver tip mounted in a power drill or electric screwdriver and generally don’t require pilot holes. Lengths range from 3/4 inch to 4 inches.
Because drywall and deck screws are not rated for strength, use nails, lag screws (also called lag bolts), or bolts when engaging in heavy construction.
Lag Bolts & Screw Eyes
Lag bolts and screw hooks and eyes have many household uses. Lag bolts are heavy-duty fasteners that feature a square or hexagonal head and a heavy, partly threaded shank. Screw hooks and eyes come in various sizes, from tiny cup hooks to very large utility hooks that can support heavy objects.
These fasteners come in larger sizes than wood screws, with shanks ranging from 1/4 inch to 3/4 inch in diameter (in 1/16-inch increments). They’re given a zinc coating for rust-resistance. Lag-bolt heads are meant to be driven with a wrench or a ratchet and socket. Before driving a lag bolt, predrill a pilot hole about two-thirds the bolt’s length using a drill bit that is 1/8 inch smaller than the lag bolt’s shank. Slide a washer onto the lag bolt before driving it in.
Also for heavy-duty fastening are bolts, which are threaded to be used with nuts and require predrilled holes. Made from zinc-plated steel, they provide a strong hold. Many sizes and types are available. Bolts are classified by length (3/8 inch and up), diameter (1/8 to 1 inch), and number of threads per inch. A nut must match the bolt’s thread count. To give the nut a firm bite, select a bolt that is 1/2 to 1 inch longer than the combined thickness of the pieces to be joined.
Bolts also are classified by type of head. Stove bolts and machine screws are turned with a screwdriver; hexagonal-head and square-head machine bolts are held with a wrench and require a nut and two washers. A carriage bolt head bites into the wood’s surface so that the bolt won’t turn when the nut is tightened.
Nails are classified by shank size and type and by the shape of the head. The main types are common, box, finishing, and casing.
Common nails, used for rough construction, have an extra-thick shank and a broad head. Drywall nails, a variation, have a thinner shank and a larger, slightly cupped head; annular-ring nails, best used for installing drywall on ceilings, have a ribbed shank that grips better. Where you don’t want a nailhead to show, choose a finishing nail. (After you drive the nail nearly flush, sink the slightly rounded head below the surface with a nailset.)
Nails, sold by the pound or in 1-, 5-, and 50-pound boxes, come in different styles and sizes. Nail lengths may be designated by inches, but the term “penny,” abbreviated as “d,” is more common. This term is a carryover from long ago when it specified the price for a hundred hand-forged nails.
Most nails are made of steel, but you can also buy stainless-steel, bronze, and aluminum nails for specialty tasks. Hot-dipped galvanized nails, coated with zinc, are rust-resistant and meant for use outdoors where they may be exposed to moisture.
Hollow Wall Fasteners
When fastening heavy objects to walls or ceilings, it is ideal to screw through the wall covering into the wall studs or ceiling joists that back the material. Where this isn’t possible—between framing members, for instance—wall fasteners can be used. Masonry walls also call for a fastener or anchor that will expand into a drilled hole.
An expanding anchor bolt is inserted into a hole drilled into solid masonry. As the nut is tightened, the anchor expands and cannot be removed.
A lead shield, inserted in a hole drilled in masonry, receives a screw or bolt that, when tightened, causes the shield to expand in the hole.
A spreading anchor has a sleeve that opens like an umbrella when a bolt is driven into it. Once installed, the bolt can be removed but the anchor is permanent.
A toggle bolt is a two-part fixture consisting of a bolt and spring-loaded “toggle wings” that pop open on the backside of the wall material, providing a sound anchor for tightening the bolt.
Metal framing connectors are often used in construction to make joining materials easier and to make joints stronger. These connectors are used throughout almost all of this book’s projects, but they are often hidden from view by wood components.
You will find many types of framing connectors in sizes that are designed to fit most standard-dimension rough and surfaced lumber. A welder or metal shop can fabricate odd sizes or decorative specialty supports.
When using framing connectors, be sure to use the size and type of nails specified by the manufacturer—these nails are generally shorter and fatter than standard nails.
Joist (and rafter) hangers, probably the most familiar metal connectors, are used to secure the butt joints between ceiling joists or rafters and the load-bearing beam, joist header, or ledger. Some joist hangers have metal prongs that can be hammered into the side of the joist (the connection to a beam must be made with nails).
Post anchors securely fasten the base of a load-bearing post to a concrete foundation, slab, or deck. In regions where there’s likely to be standing water caused by heavy rains, builders typically choose an elevated post base that raises the post 1 to 3 inches above the base.
Post caps join the top of a post to a beam. They also can strengthen a splice connection between two beams.
“Framing anchors” is a catch-all term for a variety of connectors. Hurricane or seismic anchors or rafter ties eliminate the need for toenailing (joining two members together by nailing at an angle) between rafters and a wall’s top plate, reinforcing angle brackets create solid joints between any two members that cross, and reinforcing straps strengthen post-to-beam joints.