In general, nails are of two kinds, namely, cut nails and wire nails, the difference between the two kinds being in the material and the method of manufacture.

Cut Nails

The cut nails, also called plate nails, are stamped out of a flat iron plate, in alternate, slightly wedge-shaped pieces, and the head is afterward formed on the large end of each piece. The cut nails are made in three classes, according to finish, and are called, respectively, "common," "casing," and "finish" nails. The nails known as "finishing nails," however, are far too rough for fine finished work. The length of the nail is regulated according to the "penny," which formerly had reference to the weight, but which now is purely arbitrary. Thus a three penny nail is 1 1/4 inches long; four penny, 1 1/2 inches; five penny, 1 3/4 inches; six penny, 2 inches; seven penny, 2 1/4 inches; eight penny, 2 1/2 inches; nine penny, 2f inches; ten penny, 3 inches; twelve penny, 3 1/4 inches; sixteen penny, 3 1/2 inches; twenty penny, 4 inches; thirty penny, 4 1/2 inches; forty penny, 5 inches; fifty penny, 5 1/2 inches; and sixty penny, 6 inches. The specifications which have just been given for cut nails also hold good for wire nails.

Wire Nails

Wire nails are rapidly replacing the cut nails in general use. They are now very nearly the same price and are very much stronger, so that they do not buckle up when driven into hard wood, and they are not nearly so liable to split the wood on account of their cylinder-shaped shaft, which is the same size throughout its entire length. They are made from wire, which is cut in lengths by machinery and pointed and headed. They can also be ribbed or barbed, if desired, which gives them a stronger hold on the wood. They are made with various kinds of heads, some being large and flat, so that the nail can be easily withdrawn, while others are very slightly larger than the shaft of the nail and can be made almost invisible in the finished work.

For framing, large nails should be used, from 4 to 6 inches in length. For the rougher exterior and interior finish, such as sheathing and rough flooring, nails about 3 inches long are suitable, while for the finer inside finish smaller nails from 2 1/2 inches down to 1 1/2 inches should be used. Roofing should be put on with special galvanized or copper nails so as not to rust out.