More on lead tempering:
It ws used on the backs of knife blades, but a spirit lamp was used for the edge...
The Hardeneing and Temering of Steel by Fridolin Reiser page 96
link
http://books.google.co.uk/books?id=W...dening&f=false
More in Gunsmithing by Roy E Dunlap pages 121 to 122
link:
http://books.google.co.uk/books?id=7...pering&f=false
but again although he mentions tempering in a bath of molten lead for small parts, the main procees described is the previous stage of hardening...
More on melting points, and salts used in the molten state for tempering at
http://www.weights-and-measures.com/xcommetalsalt.html
More on tempering of steels at
http://www.toolmakers-microscope.com...nd-alloys.html