An example of a common wood screw is the worm screw, which has a coarse thread and a hexagonal head.
A wood screw is used to join two pieces of wood together. Made of steel, the wood screw usually has a head designed to be used with a regular Phillips or flat-head screwdriver. A simple method of identifying a wood screw from a metal screw is to look at the shank of the screw. A wood screw will have a blank shank below the head and above the threaded area, while a metal screw will generally have fine threads running from the tip of the screw to the head, with no smooth or blank areas. The materials used to make the screw can be pure steel, brass or aluminum; galvanized steel or adhesive-coated steel are other options.
A wood screw usually has a head that can be used with a standard screwdriver.
The threads of this type of screw are intended to penetrate the walls of a pre-drilled hole. The screw is not normally used to make its own hole; however, some special type screws are designed for this. Attempting to force a wood screw into position without first drilling a pilot hole, the wood will often crack and the screw will typically not hold as well as a screw driven into a pilot hole. Using a pilot hole, the screw threads can bite without being impeded by wood chips in the hole.
One type of screw that works perfectly without a pilot hole is a drywall screw. A drywall screw will often be confused with a wood screw, even though they are not the same thing. The drywall screw is a very coarse threaded screw designed to drive into wood without a pilot hole. This type of screw is not designed for structural strength, nor is it made to securely hold two pieces of wood together. The drywall screw is more like a clamp in that it secures a deck to a wooden wall. Because it has threads along the entire length of the screw, it cannot sufficiently tighten two pieces of wood.
The blank shank of the wood screw allows the screw to rotate freely within the outermost piece of wood and pull the inner piece firmly against it, causing the threaded end to grab the wood and pull. The fully threaded drywall screw has threads that tighten into the outer piece of wood and do not allow the screw to turn freely as the end threads grip and pull the wood. This results in an overtightened screw; however, the wood may remain separate.