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A smith is a person who works in metal. A blacksmith works with iron and steel. A thousand years ago, people only knew about seven metals (iron, gold, silver, copper, tin, lead, and mercury). By color: gold is yellow; copper is red; and silver, tin, lead, and mercury are different gray colors. Iron is also a gray color if you shine it, but usually its surface is covered with a black oxide, which is a kind of rust. This black color forms very fast in a blacksmith's fire. The other metals have light colors, but iron is a dark color, so it is called the black metal in English. A smith who works the black metal is a black-smith.
Iron must be very hot to shape with a hammer. Hot iron becomes cold very soon. A blacksmith has only a few seconds to hammer a piece of iron, before it must be put back in the fire to become hot again.
A forge is a special oven for metalworking. It burns coal or charcoal in a very hot fire. A bellows pushes air into the forge, to make the fire burn hotter. The blacksmith puts pieces of iron in the fire to make them hot.
Ways to hammer iron
There are a few ways to change a piece of iron's shape with hammer and heat. Here are the most important ways that a blacksmith uses:
- Bending: hammering a piece of hot iron, to make it curve or to make it have a corner.
- Drawing: hammering on the sides of a piece of hot iron, to make it longer and thinner.
- Upsetting: hammering on the end of a piece of hot iron, to make it shorter and fatter.
A punch is a tool like a short stick of iron. The end of the punch is flat.
- Punching: A blacksmith hammers a punch through a piece of hot iron, to make a hole in the hot iron.
A chisel is a tool like a short stick of iron. The end of the chisel is sharp to cut.
- Cutting: hammering a chisel through the side of a piece of hot iron, to make two shorter pieces.
- Splitting: hammering a chisel into the end of a piece of hot iron, to make a stick of iron into a "Y" shape, to make a fork.
- Rivetting: a rivet is like a machine bolt with a head at both ends. Rivets are used to make different pieces of iron stay together. The blacksmith makes a hole in each piece of iron, where he wants the pieces to come together. A rivet is then put in the holes, and the blacksmith hammers on the rivet to make the heads at each end of the rivet.
- Welding: making different pieces of iron become one piece of iron. The blacksmith makes the pieces of iron so hot that they almost melt. Then he puts the pieces together and hammers on them so there is no line where they came together. Welding is the hardest thing for a blacksmith to learn and to do.
Hard iron and steel
Iron is one of the 92 natural elements.
Steel is iron with a little carbon in it (0.3% to 1.7% carbon by weight).
All metals get harder when a smith hammers or bends them. This is called "work-hardening". If a smith hammers or bends a piece of metal that is already work-hardened, it will crack and break. To make work-hardened metal soft again, so that a smith can hammer and bend it more, the smith anneals the metal.
To anneal iron or steel, a blacksmith heats the metal until it no longer pulls a magnet, and then makes the metal become cold very slowly. Blacksmiths can cover the hot metal with sand, so that it takes hours to become cold. This makes iron or steel very soft.
Steel acts just like iron, until a blacksmith "heat-treats" the steel. This is a special way to make the steel hot and then cold, so that the steel will become hard enough to keep a cutting edge (blade). A blade made from a piece of iron (instead of steel) will very soon become dull and will not cut. Good blades (for knives, chisels, axes, and other tools with cutting edges) are always made of steel, then heat-treated, and then sharpened.
To heat-treat steel, a blacksmith heats the steel until it no longer pulls a magnet, then makes the steel become cold very quickly. A blacksmith does this by putting the hot steel into a bucket of water and moving it around until it is cold. This is called "quenching". When this is finished, the steel will be as hard as it can be. This hardness can make it brittle, so if someone hits or drops it, it can break like glass.
The next step is to "draw the temper" or "temper" the steel, so that it will not break like glass. To temper steel, a blacksmith polishes a part of the steel so that it is smooth and shiny. The blacksmith then slowly heats the steel in the fire. When the steel is between 300 and 650 °F (149 and 343 °C), the polished steel will turn different colors. These colors do not glow in the dark; they look like dye on the polished steel. As the steel gets hotter from 300 to 650 degrees F, it will turn through the colors: yellow, then brown, then purple, then blue. Yellow means the steel will still be harder, blue means the steel will be softer (but still hard). When the steel turns the color that the blacksmith wants, he puts the steel into a bucket of water to stop the change. Different tools are tempered to different colors, but it also depends on how much carbon there is in the steel. Usually, stone chisels are tempered to yellow, and axes for trees are tempered to blue, but the blacksmith has to decide.
A blacksmith does not hammer a blade edge thin. A blacksmith hammers the steel so that the edge stays thick. After the "heat-treat" and "temper", stones are used to grind the blade edge to make it sharp.
If a blacksmith has a piece of iron or steel, but does not know which one it is, the blacksmith can heat-treat it like steel. If it does not become hard, then it is not steel. Iron will show the same temper colors as steel, but it will not be hard.
If a blacksmith has an old steel tool, and wants to hammer it into a new different tool, the blacksmith anneals the steel. The steel will then be very soft like iron. The blacksmith can then hammer it into a new tool, and heat-treat and temper it, to make a new, hard steel tool.
A blacksmith must be careful when hammering hardened steel or work-hardened iron, because small pieces can break off and fly, and these can hurt his or her eyes. Many blacksmiths wear plastic safety glasses to keep their eyes safe.
Tools and objects made by blacksmiths
Around 1850, countries like the United States of America and the United Kingdom made new ways to make steel and tools in factories. Factories now make tools faster, and for less money than blacksmiths. There are now very few blacksmiths in countries that have a lot of factories.
The few blacksmiths that are still in countries with a lot of factories, make iron that is art. These blacksmiths make gates, stair rails, and chairs and tables for outdoors. People buy this iron as art, because each piece is different from the other pieces.
- Blandford, Percy W. (1988). Practical Blacksmithing and Metalworking, Second Edition. TAB Books, a division of McGraw-Hill, Inc.
- Richardson, M.T. (1978 (orig.1889-1891)). Practical Blacksmithing. Crown Publishers, Inc. LOC 77-94507.
- Weygers, Alexander G. (1997). The Complete Modern Blacksmith. Berkeley, California: Ten Speed Press.