Staedtler hardness rating
Molly said: "As an afterthought: Could you be rating your pencil tests by the softest pencil that will polish or scratch the ingot? If so, it would explain your very soft readings. The correct way of using the pencils is to find the softest pencil that will CUT INTO the surface. You should be able to see a tiny curl or chip of lead that is peeled out of the surface."
Right on, Molly. I suggest we adopt the above as a best practice for testing lead alloy hardness with standard pencils. Start by flattening a small section of the alloy surface with a file. The base of a large caliber bullet is sufficient. Prepare the pencil by sanding a small flat or "meplat" on the tip of the pencil with 400 grit sandpaper. Then hold the pencil at 45 degrees, as if writing, and press firmly down and forward with the sharp edge. If the pencil skids over the alloy surface, even if it leaves a slight scratch, its still not harder than the lead alloy.
Work your way up to progressively harder pencils, until you get to one where the sharp edge of the pencil "meplat" really digs into the surface, pushing up a curl or mound of alloy in front of it. At that point you stop and consider the hardest pencil that will not dig into the alloy in this manner, to be the "Staedtler" rating of the alloy in question.
For example, my little store of 1in20 (tin-lead) alloy skids on a 3B but digs in on a 2B, therefore its Staedtler hardness is 3B. Some Hornady swaged lead bullets I have will skid on 4B but dig in on 3B, therefore the Staedtler hardness rating is 4B. I also suggest we stick to the Staedtler Mars Lumograph pencil sets, since the maker claims they conform to ASTM standard D-4236 for consistency. They are cheap and readily available at Office Depot and other stores.
With this method you can quickly determine the Staedtler hardness of a given alloy and begin to gauge which alloys are best for your loads and firearms. While its possible to roughly equate Staedtler hardness ratings to Brinell hardness numbers, that question is moot, so long as you stick to the pencil method for testing all your alloys. - CW