Hardening Screws

[GregLaROCHE]

What’s the simplest way to harden small screws?

[KCSO]

Depends on what steel they are made of... 01,d1 drill rod or what ever was in a box? Try htin them and quenching them in oil or water first and if that doesn't work try kasenite next.

[OldBearHair]

You might try this . Heat to red until you lose the dull look and quench in 120 degree oil. Check to see if a file will cut them. If not they are hardened. Then put in the oven to 475 degrees for 30 minutes . Then if the "sharp" file will bite into the steel somewhat, the screws should be ready. It all depends on what steel the screws were made from and there are many variables. note: If the screws are galvanized, this process will remove it.

[country gent]

Something to keep in mind unless the screw really needs to be hardened soft is better, This way the screw wears and not the holes female threads. Its easier on tooling also. A soft screw is easier to remove it breaks.
I would buy 4140 pre hard this is usually in the 45 rc range, turn the screws from it. In a pinch a allen head cap screw can be used for stock for a smaller screw. The pre hard turns and finishes nicely with no heat treat needed after.
Drill rod, and other tools steels can be used and hardened after but there is the risk of warping and deforming from the heat and quench. Another is finding little screws in the quench after LOL.

[M-Tecs]

What’s the simplest way to harden small screws?

The first question is why are the screws soft? If they were manufactured that way chances are the carbon content is to low to heat treat. If that is the case the only option is case hardening with a product like Cherry Red. https://www.midwayusa.com/product/1006364292

[GregLaROCHE]

It’s the screw that holds the flint in place on a flintlock. I’ve already made it, but now that I’m using it, I’m thinking I’d be more assured if it was hardened a little. Case hardening is what I the would be best.

[M-Tecs]

If you made it you should know what material it is made of? If it is medium or high carbon case hardening is not the appropriate hardening method.

[oldred]

It’s the screw that holds the flint in place on a flintlock. I’ve already made it, but now that I’m using it, I’m thinking I’d be more assured if it was hardened a little. Case hardening is what I the would be best.

If you decide to use a hardening compound (by far the easiest way!) then as M-Tecs suggested look for some Cherry Red compound, it's easy to find while the Kasnit that was also suggested has been off the market for nearly ten years now. Kasnit was REALLY good stuff but unfortunately thanks to some total idiot at the EPA all that is left now is just what some folks have leftover from years ago and it's all but impossible to find these days. :(