thing 17: blacksmithing punch

i’m taking a blacksmithing class. today we created our first real thing: a punch. we will use it to punch holes in things! specifically, we will be punching holes for a rivet in the tongs we are going to make next week. (which we will use in future projects. how cool is that?!) we actually started this punch last week, but that was mostly grunt work. this was originally a coil spring from a pickup truck. they were cut into “C” shape pieces. last week we straightened them out and started tapering them. this week i finished the taper, rounded it out, heat treated it and filed it down.

the heat treating is tricky. you first have to slowly heat up the pointy end until it reaches its critical temperature which is determined by it losing its magnetism. once that’s happened, you quickly cool it in a bucket of vegetable oil. oil helps cool it somewhat quickly but not too quickly like water. then you wipe off the oil and grind off some of the outside. you heat it up in a pretty low temp forge and carefully watch for the exposed metal to turn a brownish color. if it turns blue or purple, you’ve gone too far and you have to start the whole process over again. i did this part 3 times. when that’s done, you cool it in oil again and then use a grinder to smooth out the end and level off the tip. if you’ve done everything right, the pointy end is now hard and strong!

then you have to anneal the other end, which is just heating it up in a hot fire and letting it cool down by itself at room temperature. this makes it softer. you want the end you are hitting with a hammer to have some give, and you want the pointy end to be hard. so in the future, i will heat up a piece of metal that needs a hole, and hit this punch through it!