When, years ago, my truck’s sideview mirror came off in my hand 1000 miles from home, I figured I’d have to get a new one at the local salvage yard. My father-in-law, though, had better solution. All that was wrong with the old one was that a threaded rod was had broken, so Big Tom rummaged through the workshop for some rod stock the right size, picked up a matching hexagonal die and a wrench, and a few minutes later I had a home-made replacement. That was 1995: I still have the truck, and I still have the mirror. And I also have my own hexagonal dies, like Irwin’s 6520 – a ¼-inch version with NC 20 thread. That means it will form a 20-TPI thread in quarter-inch rod stock. I have other dies, too, to fit 3/16” and 5/16” stock. They’re all made in Ohio by American Tool and sold under the Irwin/Hanson brand.
This kind of die is a flat hexagon, ¼ inch thick, that you turn with a 1-inch wrench. They’re made of a high-carbon steel alloy. One side bears a label with the size, while the other has one that says “Start from other side.” You start that way because the “start” side is missing the first set of cutters, which lets it fit onto the cut end of a rod. Instead of having one hole like a hex nut, a die has three additional holes that like clover leaves to let shavings escape. They also let you apply cutting oil while using the die.
I’ve used my dies many times for jobs like repairing damaged bolts and threading rod stock for household repairs. I’ve also used them to extend existing threads on bolts.
You need a bench vise and a long-handled wrench if you’re going to use these, and it’ll take some effort to cut raw steel. These dies are good for common steel stock, but usually aren’t hard enough to thread high-carbon steel except in the smallest diameters.