One of the most common discussions among builders concerns whether screws or nails are better for assembling a given project. Each has its supporters and detractors, and each fastener has advantages and disadvantages. Sometimes either would be a good choice, but sometimes only one can do the job properly. Understanding the strengths and weaknesses of each type of fastener is the only sure way to make a good decision.
It is hard to imagine that even a young child does not know what a nail is. Nails are so simple and straightforward that anyone can understand how they work. In addition, you need only one tool--a hammer--to properly assemble a project using nails, regardless of the size or style of the nail. For this reason alone, nails are an attractive fastener.
Unlike nails, wood screws are much less convenient to use. Not only will you need different sizes of screwdrivers to use with different size wood screws, but you will need a drill, along with a properly sized drill bit, in order to make pilot holes for the screws. You may also need a countersinking bit, which is used to make a larger hole so the head of the screw will not extend above the surface of the wood. All of this preparatory work can be time-consuming.
The trade-off for the extra work that screws require is increased holding power. A properly drilled and countersunk wood screw creates an extremely strong joint with no other help--a joint which can be easily disassembled with a screwdriver. Nails can make very strong joints if they are reinforced with glue, but the joint will then be permanent. Of course, glue can also be used with a screwed joint for even greater strength if disassembly will not be required.
When thin or end-grain wood pieces have to be joined together, the choice between the two fasteners is not so clear. You may have to drill pilot holes to keep nails from splitting the wood, as well as putting a little glue in the holes to increase the nail's holding power. And you may not be able to use screws at all if the wood is too thin.
Deciding which fastener looks better for a given project depends on the project. Nails can be easily driven level with the surface of the wood, or even driven below the surface using a simple tool called a nailset; the hole can then be filled with plastic wood. Countersinking screw heads and covering them with plastic wood is also possible, but the larger size of the patch may be too obvious. You can make wooden pegs to fit in the holes and perhaps even extend above the surface for a decorative effect, but this requires extra work. The method and fastener you choose is totally up to you.