Most nails are made flat or chisel-shaped at the point, that they may not split the wood. In driving a nail with a flat point, the length of the point should be placed across the grain of the wood, and then it will hardly ever split it, but if otherwise, the nail, acting as a wedge, opens the grain and splits the wood.
The screws used by carpenters, smiths, and others, for fastening wood or metal-work together, are generally made by machinery. A piece of wire of the required thickness and length is first cut off, which is then placed in a hole or mould, with its upper orifice “countersunk” as in the annexed cut, and the head of the screw is formed by beating the upper part of the piece of wire into the counter-sinking of the mould. It is then called a “blank,” and a number of these blanks are dropped into holes bored round the periphery of a wheel which revolves slowly against a small circular saw driven with great rapidity, and cutting a “thread” or slit in the head of each blank in turn as it comes into contact with it; the wheel continuing to revolve, each screw when it gets to the bottom drops out, so that the holes when they again arrive upwards are ready to receive fresh blanks. The worm, if cut by hand, is made by means of a die of hard steel, having a hollow screw cut in it, which is screwed slowly by a backward and forward movement on to the blank, cutting it into a “worm;” when this is done by machinery, the die is held fast while the screw is worked by a rotatory movement into it. The best screws for wood are slightly tapered, which enables them to be driven much more easily, while they hold equally fast. Large screws for mechanical purposes are cut by a “lathe,” the bar revolving whilst a cutter is held to it, and moved onwards by a pattern screw. Small screws for various purposes can be easily cut by means of a “screw-plate,” having holes of graduated sizes cut inside into hollow screws, which is placed on the end of the wire, and gently turned round till it is sufficiently cut.
Pins are made from brass wire drawn out in the usual manner (see “Wire-drawing”). It is first straightened and then cut off into lengths sufficient for two pins; these are pointed at each end by holding them to a wheel, about two or three dozen at a time, turning them all round at once by means of the thumb and fingers. The wheel is not made of stone, but of steel, having the edge cut into fine notches like a file (see “File-cutting”). After the wires are pointed at each end, they are cut in the middle. The heads are made by coiling some brass wire round another piece of wire exactly the size of the pins for which they are intended, and with a sort of chisel cutting off two of these coils at a time. The accompanying figure represents the coil to be cut up into a string of heads, and one of them separate. These are fixed on to the pointed wires by a machine acting by means of a lever, by which they are compressed into the right shape and at the same time made to hold on tightly. The pins are then cleaned by boiling in some weak acid or a solution of tartar, and have next to be “tinned” or “whitened,” which is done by placing them in layers with grain-tin and cream of tartar, and boiling them for some time till they are coated with the tin; thus they are truly “electro-plated,” although at the time when this process was invented no knowledge of electro-plating existed, and the theory of the process was not understood. The pins are afterwards cleaned and brightened by shaking them in leather bags with bran, which is afterwards blown away by a blowing-machine; the pins are then placed in papers (folded by a sort of crimping-machine), which are put into a kind of vice, having a number of notches cut in it corresponding to the number of pins to be stuck in one row, and into these notches and through the paper ridges the pins are rapidly passed by children.