How to make the perfect killing machine.
Swordsmiths through history have faced a big problem when making swords. Iron is flexible, and this makes it excellent as a blade, since it will bend when struck, rather than breaking in combat – half a sword is not much use in a battle! But because iron is malleable, it will not keep an edge, meaning that after half an hour’s fighting, a pure iron sword will turn into something little better than a long club. Steel (an alloy of iron and carbon) is much harder, so it will keep its edge even after slicing through shields and armour. But steel is also brittle, making it vulnerable to sideways, parrying blows. A sharp steel sword will cut through almost anything, but a good whack with a wooden staff would probably break it. Through the centuries, swordsmiths have attempted to marry the strengths of steel and iron, and to minimise their weaknesses by forging swords with iron cores and steel cutting edges. Welding core and edge together was – and is – a hugely skilled process, and can go wrong at any stage if impurities concentrate at a point. This can be particularly upsetting for a swordsmith who has spent days hammer-forging a blade.
1. Choose your metal. The iron made the sword. Getting the best metal was the most important part of making a good blade. However, apart from the occasional meteorite, there is very little pure iron on Earth. For swordmaking, iron was often obtained from bogs or mined; bog iron is carried in liquid form into the bog, then concentrated by anaerobic bacteria, producing small lumps of iron. This source of iron is renewable, as new lumps appear in 15 to 20 years.
2. Forging. Forging is when the smith hits the hot metal with a hammer over and over again, working it into shape. The best swords fuse iron and steel, and heating the metals makes thousands of tiny welds, joining the two materials together. Forging also spreads any impurities evenly through the sword, reducing the chance of the weapon breaking. In the best swords, bars of good iron are twisted together, further spreading out any impurities. The bars are welded into a solid core, and the steel edge welded on to the core.
3. Annealing. As the swordsmith is forging the blade, they will usually return it to the heat several times, and let it cool again without working on it. This helps to reduce irregularities in the blade. Once it has been shaped, the sword is annealed by heating it to a precise temperature and allowing it to cool very slowly. This is done either by allowing the forge fire to cool, or by burying the sword in hot sand.
4. Grinding. Swordsmiths through the centuries have used different methods to grind the blade, from water-powered wheels to sand on leather, but hand files were the most common tools employed. The aim of grinding is to remove the material that cannot easily be removed by the forging process. The fuller – the groove down the middle of the sword – and any engraved designs are also added at this stage.
5. Hardening. The shaped sword is reheated until it glows a dull orange colour. At this heat, the metal becomes non-magnetic. The sword is then quenched in water. This helps to line up the crystalline structure of the iron and steel in the sword and makes it harder. But quenching can also make the sword brittle. To overcome this, smiths must heat the blade again, for the next stage in making the sword.
6. Tempering. To overcome the brittleness produced in the hardening, the sword has to be reheated to a lower temperature than before. In the days before temperature gauges, this was done by colour; the smith heats the sword until the edge is a straw colour, and the centre – with its thicker metal – a deep purple. The blade is then slowly cooled. This slow cooling reintroduces some flexibility into the sword, making sure it does not break in battle.
7. Completion. Although the sword is now forged, it looks dirty and crusted, so it has to be cleaned. Abrasives, such as sand on leather, are used to file and clean the sword, until it is ready for sharpening on a whetstone. After a final sharpen, pattern-welded swords are etched to highlight the pattern on the blade. The most impressive swords have hilts made of precious metals, with jewels inset, while the pommel and guard are adjusted to keep the weapon balanced. The sword is now ready for use.
DID YOU KNOW? Fullers are called ‘blood grooves’ but this is a misnomer. They were added to lighten and strengthen the sword.