Nails, in building, are small pointed spikes, generally with a flat, or convex head, made of brass, iron, or other metal; which, when driven into wood, serve to connect several pieces, such as boards and laths, or to fasten a piece of timber, etc.
Nails are divided into numerous classes : their figure and size vary-according to the purpose for which they are designed; and which it would be superfluous to enumerate. As they are of such essential importance in building, the arts, and economy in general, several privileges have been granted for new inventions, or improvements, in the manner of casting, or manufacturing them. On account of their ingenuity, the following patents deserve to be mentioned ; namely, Mr. Finch's, obtained in 1790; Mr. Clifford's, registered in the same year ; and Mr. Spencer's, granted in 1801. But, as these processes can only be understood and practised by manufacturers, we cannot enter into any detail, but refer the curions reader to the 7th, 9th, and 15th, vols, of the Repertory of Arts, etc; where full specifications are inserted; and Mr. Spencer's patent is illustrated with an engraving.
In the year 1787, the Society for the Encouragement of Arts, etc. conferred a bounty of three guineas on Mr. William Rich, of Yald-ing, Kent, for his invention of a machine, which is represented in the following cut, in the action of drawing cut a spike.
Nail And Bolt-Drawer.
A, B, the piece of timber, in Which the nail or spike C, intended to be drawn, is inserted.
F, a square staple, turning on a centre at G and, if the spike to be drawn, be held between the lever and the staple, any pressure at D, will act with an effect proportionate to the distance a F, and D a; and the workman will thus be enabled to exert a very great force against the spike C
Mr. Rich's nail-drawer is both simple and ingenious; it is emi-nently serviceable in breaking up ships, and on other occasions, where large nails and spikes have been driven deeply into wood, from which they are to be extracted.