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Home-Repair Materials Basics

Nails, Screws, and Bolts

Most repair projects require such fasteners as nails, screws, glues, and bolts. And there are many of each type to choose from! The following are some of the most common types of fasteners and advice on how to select the right one for your fix.


The easiest way to fasten two pieces of wood together is with nails. They are manufactured in a variety of shapes, sizes, and metals to complete almost any fastening job. Most commonly, nails are made of steel, but other types -- aluminum, brass, nickel, bronze, copper, and stainless steel -- are available for use where corrosion could occur. In addition, nails are manufactured with coatings -- galvanized, blued, or cemented -- to prevent rusting and to increase their holding power.

Here are the common nail types and sizes.
�2006 Publications International, Ltd.
Here are the common nails and their sizes.

Nail size is designated by penny size, originally the price per hundred nails. Penny size, almost always referred to as "d," ranges from 2 penny, or 2d (1 inch long), to 60 penny, or 60d (6 inches long). Nails shorter than 1 inch are called brads; nails longer than 6 inches are called spikes. The length of the nail is important, because at least two-thirds of the nail should be driven into the base, or thicker, material. For example, a 1X3 nailed to a 4X4 beam should be fastened with an 8 penny, or 8d, nail. An 8d nail is 21/2 inches long; 3/4 inch of its length will go through the 1X3, and the remaining 13/4 inches will go into the beam.

Nails are usually sold by the pound; the smaller the nail, the more nails to the pound. You can buy bulk nails out of a nail keg; the nails are weighed and then priced by the retailer. Or you can buy packaged nails, sold in boxes ranging from 1 pound to 50 pounds. For most repairs, a few 1-pound boxes of popular nail sizes will last a long time. What follows are some of the most common nail types.

Common Nails: Used for most medium to heavy construction work, this type of nail has a thick head and can be driven into tough materials. Common nails are made from wire and cut to the proper length and are available in sizes 2d through 60d.

Box Nails: Lighter and smaller in diameter than common nails, box nails are designed for light construction and household use.

Finishing Nails: Finishing nails are lighter than common nails and have a small head. They are often used for installing paneling and trim where you do not want the nail head to show.

Roofing Nails: Usually galvanized, roofing nails have a much larger head than common nails. This helps to prevent damage to asphalt shingles.

Drywall Nails: Nails made for drywall installation are often ringed and have an indented head. Annular-ring nails have sharp ridges all along the nail shaft, providing greater holding power.

Masonry Nails: There are three types of masonry nails designed for use with concrete and concrete block: round, square, and fluted. Masonry nails should not be used where high strength is required. Fastening to brick, stone, or reinforced concrete should be made with screws or lag bolts.

Tacks: Available in both round and cut forms, tacks are used to hold carpet or fabric to wood. Upholstery tacks have decorative heads.

Corrugated Fasteners: Corrugated fasteners, also called wiggly nails, are used for light-duty joints where strength is not important. The fasteners are set at right angles to the joint.

Screws provide more strength and holding power than nails. Additionally, if something needs to be disassembled, screws can easily be removed. Like nails, screws are available with different coatings to deter rust. They are manufactured with four basic heads and different kinds of slots. Flathead screws are almost always countersunk into the material being fastened so the head of the screw is flush with (or lower than) the surface. Oval-head screws are partially countersunk, with about half the screw head above the surface. Roundhead screws are not countersunk; the entire screw head lies above the surface. Fillister-head screws are raised above the surface on a flat base to keep the screwdriver from damaging the surface as the screw is tightened.

Most screws have slot heads and are driven with slotted, or standard, screwdrivers. Phillips-head screws have crossed slots and are driven with Phillips screwdrivers. Screws are measured in both length and diameter at the shank, which is designated by gauge number from 0 to 24. Length is measured in inches. The length of a screw is important because at least half the length of the screw should extend into the base material. Tip: To prevent screws from splitting the material, pilot holes must be made with a drill before the screws are driven.

For most home repair purposes, wood screws will suffice. Sheet metal screws, machine screws, and lag screws also come in various types. If you're trying to replace one of these screws, take an old screw with you to the hardware store.

Here are the most common types of screws and screw-like fasteners.
�2006 Publications International, Ltd.
Here are the most common types of screws and screw-like fasteners.

Drilling for Wood Screws
For optimum wood screw performance, you need to drill first. Click here for a guide.

Wood Screws

Wood screws are usually made of steel, although brass, nickel, bronze, and copper screws should be used if there is potential for corrosion.

Sheet Metal Screws

Use this type of screw to fasten pieces of metal together. Sheet metal screws form threads in the metal as they are installed. There are several different types of sheet metal screws. Pointed panhead screws are coarse-threaded; they are available in gauges from 4 to 14 and lengths from 1/4 inch to 2 inches. Pointed panheads are used in light sheet metal. Blunt panhead screws are used for heavier sheet metal; they are available in gauges from 4 to 14 and lengths from 1/4 inch to 2 inches. Both types of panhead screws are available with either plain or Phillips-head slots.

Roundhead Screws

Partial-tapping roundhead screws have finer threads; they can be used in soft or hard metals. They are available in diameters from 3⁄16 inch to 11/4 inches. Self-tapping roundhead screws are used for heavy-duty work with thick sheet metal and are available in diameters from 1/4 inch to 2 inches and in lengths from 1/8 to 3/4 inch. Both types of roundhead screws are available with either plain or Phillips-head slots.

Machine Screws

Machine screws are blunt-ended screws used to fasten metal parts together. They are commonly made of steel or brass. Like other fasteners, they are also made with coatings -- brass, copper, nickel, zinc, cadmium, and galvanized -- that help deter rust. Machine screws are manufactured with each of the four basic types of heads -- flathead, ovalhead, roundhead, and fillister-head -- and with both plain and Phillips-head slots. They are typically available in gauges 2 to 12 and diameters from 1/4 inch to 1/2 inch and in lengths from 1/4 inch to 3 inches.

Lag Screws

For light work, lead, plastic, or fiber plugs (called anchors) can be used to hold screws. But for larger jobs and more holding power, lead expansion anchors and lag screws are used. Lag screws are heavy-duty fasteners. They are driven with a wrench and are used primarily for fastening to masonry or wood framing. The anchors are inserted into holes drilled in the masonry, and the lag screws are driven firmly into the anchors.


Bolts are used with nuts and often with washers. The three basic types are carriage bolts, stove bolts, and machine bolts. Other types include the masonry bolt and anchor, toggle bolt, and expansion bolt, which are used to distribute weight when fastening something to a hollow wall. Machine bolts are manufactured in two gauges: fine-threaded and coarse. Carriage and stove bolts are coarse-threaded. Bolt size is measured by shank diameter and by threads per inch, expressed as diameter by threads (for example, 1/4X20). Carriage bolts are available up to 10 inches long, stove bolts up to 6 inches, and machine bolts up to 30 inches. Larger sizes usually must be special ordered.

Carriage Bolts

Carriage bolts are used mainly in making furniture. They have a round head with a square collar and are tightened into place with a nut and wrench. The collar fits into a prebored hole or twists into the wood, preventing the bolt from turning as the nut is tightened. Carriage bolts are coarse-threaded and are available in diameters from 3⁄16 to 3/4 inch and lengths from 1/2 inch to 10 inches.

Stove Bolts

Stove bolts aren't just for stoves; they are quite versatile and can be used for almost any fastening job. They are available in a wide range of sizes, have a slotted head -- flat, oval, or round, like screws -- and are driven with a screwdriver or tightened into place with a nut and wrench. Most stove bolts are completely threaded, but the larger ones may have a smooth shank near the bolt head. Stove bolts are coarse-threaded and are available in diameters from 5⁄32 to 1/2 inch and lengths from 3/8 inch to 6 inches.

Machine Bolts

Machine bolts have either a square head or a hexagonal head. They are fastened with square nuts or hex nuts and are wrench-driven. Machine bolts are manufactured in very large sizes; the bolt diameter increases with length. They are either coarse-threaded or fine-threaded and are available in diameters from 1/4 inch to 2 inches and lengths from 1/4 inch to 30 inches.

Masonry Bolts and Anchors

These work on the same principle as the lag bolt or screw; a plastic sleeve expands inside a predrilled hole as the bolt is tightened.

Hollow Wall Bolts

Toggle bolts and expansion bolts are used for fastening lightweight objects, such as picture frames, to hollow walls. Toggle bolt wings are opened inside the wall by a spring. Expansion bolts are inserted into an expansion jacket, which expands as the bolt is tightened. The bolts are available in diameters from 1/8 to 1/2 inch and lengths up to 8 inches for walls as thick as 13/4 inches.

Now let's consider an entirely different way of fastening things: with adhesives. Details are in the next section.