I have just learned about a beautiful low tech solution to measuring the hardness of a lead alloy. It is the pencil test.

Many folks cast their own bullets from lead scrap. As you can imagine, folks search where they can for the scrap. This results in all sorts of differing alloys: pure lead from lead pipe and lead shielding from big cables; lead-tin alloys from various solders; lead-tin-antimony alloys from wheel weights and old lead type. Pure lead is very soft. Type metal, or linotype, is much harder. The hardness of a cast lead bullet has a great effect on its shooting characteristics. Sometimes, circumstances are such that unknown mixes must be tested for hardness to determine their usefulness as bullets.

I just learned about the “drafting pencil test”. Various harness of pencils are tested on a sample of the lead to determine the lead’s harness. Example: a 2B pencil scrapes lines in the lead sample and a 4B pencil writes on the lead; this lead sample has a brinell hardness number around twelve. the 2B pencil would write on a harder piece of lead and the 4B pencil would scrape lines in a softer piece of lead. I’m sure someone has made a chart converting the pencil test to brinell hardness numbers.

Not everyone has access to other forms of hardness testing, but most folks can find an art supply store where they can buy an assortment of pencils.

I love this kind of thing.