On Tue, 27 Nov 2007 21:43:15 GMT, Ecnerwal
wrote:

NoOne N Particular wrote:

Or rebar??

Unknown random steel - useless for toolmaking, as it's far too variable.
Car springs either are, or might as well be, 5160. If you heat treat a
car spring as if it's 5160, the odds are excellent that things will
work.

Rebar will meet its tensile strength test, and you know nothing else
about it. You know a tiny bit more about rebar that's rated as weldable,
but still not much.

wrote:

What about brake drums and rotors?

Usually cast - useless for cutters. Large ones make a nice base for a
grinder.

Also useful for firepots on homemade coal forges, from what I gather.

If you go to one of the machine tool suppliers (MSC, McMaster-Carr,
etc.), you can find extremely nice stuff as drill rod (round) and tool
steel flats (rectangular), in your choice of various formulations (W1
and O1 being typically the most useful for home-shop processing). In the
smaller sizes the prices are quite reasonable, considering that it's
supplied at a known size, as a known alloy, in a known condition.