Hello, Patsak, you wrote: In the Middle Ages, by the way, about the same principle used , applying against the knights of an arrow chained in an armor with the long and narrow tempered tip which punched the external armor and deeply stuck into a body. Only they also aggravated it - began to do these tips not fixed in a staff, and simply feeblly fayed on it. Therefore, when in a fight fever such arrow tried to pull out from a wound - the construction was disunited, and the person remained with a piece of iron in a side which one end stuck out at it between edges, and another - with each wave of a sword crawled there-here together with an armor. Sensations, possibly, were inexpressible. Image: 320px-Bodkin1.jpg it seemed To me that the thickening on an edge blunts a spear and reduces punching ability. As now understood, boards and an armor of that time punched and so, at the expense of the weight, and the thickening played an important practical role.