The old man next door had a round bar that was used for making starter holes for fence posts. It was about 4-5 feet long with a formed 'mushroom' head and a squared section about 8-9 inches long near the point, which was very hard. The bar appeared to be soft iron/mild steel. My father explained that the hard point was achieved by splitting the end of the bar into 4 quadrants, inserting part of a rat tail file in the middle and forging the 4 quadrants around it. The temperature at which the job was quenched in water was critical, he told me. As the forged point cooled down the correct time was when a certain colour reached the point. I think it was orange! Any one ever done this?