The nature of "plastic forming of metal", as the work of a blacksmith would be defined by a contemporary technologist, is obtaining the final product solely by squeezing, extending or planishing of material. These are activities well known to all of us, at least from playing with plasticine. The similarity between forging iron and forming shapes in plasticine is even greater than it seems to be. Iron, like cold plasticine, is hard and fragile, it softens only after it is heated though its temperature has to be significantly higher. A popular saying "Strike while the iron is hot" is absolutely true though the word hot does not say much about the real temperature of the forged iron. The blacksmith from the past had no possibility to define objectively and exactly the temperature of the forged iron. He could estimate it only on the basis of the colour of the glowing embers, thus a more precise method suggests to forge iron only when it acquires a red or white colour. The contemporary blacksmith having at his disposal a large anvil, heavy hammers and practically unlimited amount of iron, heats metal to the maximum temperature and forges it with strong hammer strikes. Inaccuracy unavoidable in this type of processing is removed later by polishing. Such a work style was unacceptable for the ancient smith. While forging at the temperature of almost 1000°C visible pitting appears on the surface of iron caused by rapid oxidation, large parts of metal fall off in the form of hammer scale. Traces of soft hammer strikes visible on the surface of many preserved iron objects prove that in ancient times forging was not only the rough processing but also finishing and the lack of the mentioned pitting indicates that the last stage of forging was carried out in the temperature of red heat ~ 700 °C at the most.

Most probably only large objects which did not have to preserve exact shapes were forged in high temperatures. Smaller objects or fragments requiring more precise finishing were processed in the temperatures of 500 ÷ 700 °C or even when they were completely cold. However, cold forging hardens the material gradually which may lead to its delamination or breaking. In order to avoid it the forged object has to be red heated from time to time, which softens it again. At the beginning only small hammers were used for forging and only at the end punches were used as well as files and whetstone for correction. Therefore, holding an object supported by an anvil was possible, which increased the precision of strikes. It reminded more the work of a goldsmith than that of a blacksmith. Modest equipment of the ancient forging shop, as compared to the contemporary one with a welding machine, a drill, a grinder or a large anvil, forced the ancient blacksmith to employ time-consuming methods about which we have just a vague idea.

This long time required limits our demonstrations to making only the simplest objects such as buckles, belt fittings, arrow-heads, spearheads or small knives.


A FALCATE KNIFE


IRON BELT FITTINGS