Rule of Thumb for Hardening Lead

[detox]

For every 1% additional tin, Brinell hardness increases 0.29

For every 1% additional antimony, Brinell hardness increses 0.92

Sample equation:
Brinell= 8.60 Brinnell pure lead + (0.29 x Tin percentage) + (0.92 x Antimony percentage)

For example, if you increase the amount of Tin by 10% and the amount of antimony by 5%, the Brinell hardness of your lead will be 16.1

Brinell hardness 16.1 = 8.60 (0.29 x 10) + (0.92 x 5)

Info furnished by my Lee Precision Melter manual ;-)

[williamwaco]

Linotype is 84/4/12

That would be

8.6 + (.29*4) + (.92*12)

8.6 + (1.16) + (11.4)
= 21.6


Not bad!
Closer than a thumbnail scratch.

[runfiverun]

when did pure lead become 8.6 bhn?

[alfloyd]

Since Rotometals put that value in their lead alloy chart.

Lafaun

[cbrick]

For every 1% additional tin, Brinell hardness increases 0.29

For every 1% additional antimony, Brinell hardness increses 0.92

Sample equation:
Brinell= 8.60 Brinnell pure lead + (0.29 x Tin percentage) + (0.92 x Antimony percentage)

For example, if you increase the amount of Tin by 10% and the amount of antimony by 5%, the Brinell hardness of your lead will be 16.1

Brinell hardness 16.1 = 8.60 (0.29 x 10) + (0.92 x 5)

Info furnished by my Lee Precision Melter manual ;-)

Major problem with your example, the percentage of Sn should not exceed the percentage of Sb to prevent the free Sn areas throughout the boolit. Next, tin will only mildly harden lead to a point beyond which adding more tin will not significantly harden the alloy. A 10% Sn alloy would be very lite and very expensive.

Yes, Roto Metals has that formula on their web site but looking at it I'm not sure if they are using an 8.6 BHN alloy as a starting point or . . . ?? Pure lead is 5 BHN.

Rick