Originally Posted by
chasw
Thanks, Molly and Rob. This is useful information. As I begin to gather data from using my new pencil set on samples from my store of boolit alloys, I am beginning to map out a scale of sorts - call it the Staedtler Scale, after the makers of these fine artist's pencils. So long as one sticks to that widely available brand of pencils and uses the correct technique, results will be similar. Molly observed spacing of about 1-3/4 BHN between some of the grades, perhaps at the softer end of the scale. Here's what I've gathered so far:
6B = Pure lead, about 5 BHN
5B
4B
3B = 1in20 tin/lead alloy, age softened, about 10 BHN
2B
B
HB = Lyman no 2 alloy, about 15 BHN
H = Linotype, supposedly about 22 BHN, but that seems high
2H
3H
4H
I offer this cheap but effective method of testing relative hardness, not particularly to convert pencil numbers to Brinell numbers, but rather as an alternate scale for boolit casters, with reference points to known alloys. If I pick up some scrap lead, or buy alloy from a smelter, I can quickly find out where it lies, relative to those other alloys. For example, my small stock of LaserCast brand commercial lead projectiles tested HB. I never had any luck with them, I've been saving them for the furnace, now I know approximately where they fit in as feedstock.
The bullets I cast from Lyman no 2 do very well in my rifles, with no leading at all. But methinks that alloy is too hard to maintain a tight seal in my revolver loads. So I'll try some of the 1in20 alloy, maybe with some Lino mixed in to boost it up into the 2B range. - CW