There are some 300 varieties of nails, named chiefly from the shape of their heads and points, or according to the particular use for which they are intended.

No attempt will be made to describe them all, but it may be useful to the student to know the names and characteristics of some of those in most common use for building and engineering work.

The thickness of different classes is expressed by the terms "fine," "bastard," "strong;" and their weight is generally given in lbs. per 1000, and their length in inches.

In former times nails were described according to their price per 100 - thus, "tenpenny nails" and "fourpenny nails" were those costing 10d. and 4d. per 100 respectively. These terms are still sometimes used, but their meaning is now indefinite. It varies in different localities, and no longer refers to the price of the nails. The term "Tenpenny nails" now generally means nails about 23/4 inches long, not nails at l0d. per 100. In the same way "Sixpenny nails" are generally 11/2 inches long, "Eightpenny" 21/4 inches, and "Twentypenny" 31/2 inches. Makers differ, however, as to the lengths corresponding to the different names.

Cast Nails, made by running molten iron into moulds, are brittle and inferior in strength, but cheap. They are used for horticultural purposes, for lathing, and for many other purposes in common work.

Malleable Nails are made in the same way as cast nails, but are afterwards rendered malleable by the process described at page 266. They can be made thinner than the common cast nails.

Hand-Wrought Nails are forged by manual labour. They are tougher and stronger than other varieties, and will bear clenching, but are more expensive. Their angles are sharp and clear, and the shanks are slightly compressed just under the heads.

Cut Nails are of a cheaper description, cut by machinery out of sheets of iron.

1 Manufacturers' Circulars.

Patent Machine-Wrought Nails are made out of wrought iron pressed while red-hot into shape by grooved rollers, then cut up, and the heads formed by a die. They have not such sharp clean angles as the hand-wrought nails, and are not so strong or elastic. The shank under the head is rather flattened out, and their grip is maintained by the shank being slightly thicker near the point than in the centre. They are slightly cheaper than hand-wrought nails, and at present Rose and Clasp nails are the chief varieties made.