Longer ago than I care to remember, I saw a picture of a gadget designed just to make this easier, and a few years back I made one*. This knowledge might come in handy for preppers, so here's how to do it.
You know that steel strap they use to hold bundles of brick and such together? You need some of that (you can often find some being thrown away at home improvement stores, or where someone's building a house).
This piece is 7" long. (Yes, the strap is a bit rusty; it's trying to rain outside, so pulling the buffer & wire brush out of the shed wasn't happening.)
Break or cut it in two.
Find a screw and nut of suitable size
You can use a pop rivet if you have the tool for it. I like the screw and nut better.
Drill a hole through both pieces near one end, just large enough for the screw to fit through. Put the screw in and snug the nut down; only needs to be tight enough to give smooth movement when you pivot the arms. Then cut the screw off so it sticks out just a bit from the nut.
Now take a hammer -- a ball peen is best, but any will do -- and peen the end of the screw down, especially at the edge. That will spread the end out, and keep the nut from ever being able to come off.
And it's almost done.
Here I have a screw, just an ordinary screw picked at random. Find a drill bit that'll make a hole just big enough for the screw to slip through.
Drill a hole in one arm of your tool.
Slip the screw through the hole so that the other arm, when rotated over, traps the head.
You can hold it by hand, or you can clamp the ends in a vise as you cut or grind the screw to length, and then file or sand the end smooth. You won't burn your fingers trying to hold it as it gets hot, and you don't have to worry about that moment it slips from your fingers and vanishes into the ether, never to be seen again.**
*Not long after that someone told me just where I'd seen it: the Brownell's catalog. So if you'd rather buy it than screw with making your own, they have them. And lots of other stuff, too; they're a good company to do business with.
**A bunch of screws vanished from my ken are probably hiding in a corner of Schrödinger's Box, where the cat is playing with them as he waits for someone to open the damn thing.