Illustration: FIG. 5. (‡ MACHINED BRADS.)

Nails are made both by hand and machinery, the former being called

“wrought,” and the latter “cut” nails. For making nails by hand, a

hammer and an anvil only are used. The “nailor,” having put several

rods of iron of the required size into the fire to get hot, that he

may use one after the other, and so lose no time, takes one out and

with the hammer beats it to a point, leaving a little shoulder (fig.

1). He then places it (at the part where the dotted line is in the

figure) on a wedge fixed to the anvil, and with a blow of the hammer

divides it; it is taken up by tongs, dropped into a hole in the

anvil, and the shoulder beaten flat; this is called a “tack” (fig.

2), for a “clasp nail” the head is made of a different form by a

particular way of striking it (fig. 3), and the form of the hole in

the anvil determines whether they shall be square or round; wrought

“brads” have the form of fig. 4. These are the principal forms of

nails, but many others are made by soldering shanks to cast heads, as

coffin-nails, and some (chiefly used by gardeners and plasterers for

driving into brickwork) are made of cast-iron. Machine-made nails are

cut by compression from a sheet of iron. Brads are cut out, simply,

as in fig. 5, which uses up the whole of the iron without any waste,

and requires no finishing; but other forms of nails are cut first

into simple wedges, and have the heads finished afterwards either by

the blows of a hammer or by compression.

Illustration: CUTTING BRADS.

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 Boy's Book of Industrial Information · 第 129 / 388 题