Mechanick Exercises, or the Doctrine of Handy-Works

Heat. Thirdly, a sparkling or welding heat.

The blood-red heat is used when iron already has its shape and size—as square bars and iron plates sometimes do—but may need a little hammering to smooth it. In this case, use the face of your hand-hammer and, with light, flat blows, hammer down the irregular bumps into the body of your iron until it is smooth enough for the file. Note that it is beneficial for a good craftsman to hammer his work as accurately original: "true" as he can; fifteen minutes spent at the forge may save him an hour of work at the vise.

The flame or white heat is used when your iron does not yet have its shape or size but must be forged into both. In that case, you must take a piece of iron thick enough and use the peen original: "pen"; the wedge-shaped or rounded end of a hammer head opposite the face of your hammer (or, depending on the size of your work, use two or three pairs of hands with sledgehammers) to batter it out. Craftsmen call this "drawing it out" until it reaches its width and is quite near its intended shape. Through several rounds of heating, if your work requires them, you can frame it into the correct shape and size; then, use the face of your hand-hammer to smooth your work and remove the dents made by the peen, just as you did with the blood-red heat.

A sparkling or welding heat is only used when you fold your iron over original: "double up" to make it thick enough for your purpose, and then "weld" or work the layers into one another to create one solid piece original: "entire lump". It is also used when you join several bars of iron together to make them thick enough for your purpose and work them into a single bar. Alternatively, it is used when you are to join or weld two pieces of iron together end-to-end to make them long enough. In this case, you must be very quick at the forge; when both ends have achieved a good heat throughout, and the inside of the iron is almost ready to melt original: "run" as well as the outside, you must very quickly snatch them both out of the fire together, and (after you have with the edge of your...