On Mon, 29 Aug 2011 17:57:03 -0500, Karl Townsend wrote:

On Mon, 29 Aug 2011 16:20:09 -0500, Tim Wescott
wrote:

I kinda asked this question once before, and got a bunch of answers that
all seemed off the point. So I'm going to try again, and (hopefully)
make my question specific enough this time.

Everybody tells me "use 12L14, it's really easy to machine". I'm
willing to accept that -- I'm using steel that I get surplus, and

snip

what I buy at the store. So, basically, something that's easy to
machine, but that'll harden up to something between a grade 5 bolt and a
grade 8 bolt.

Tim, I can't remember what you got for machines. I use plain old
structural cold rolled for most stuff. Its cheap and i got a lot of it.
Machines easily on my equipment.

If i need any perfomrance at all, I move up to 4140 (I assume that's
what you mean by 41L40) It does machine a bit harder but not bad. On my
equipment again.

IMHO 12L14 is an expensive low performance material. I'd only use it if
my machines were marginal as it machines like butter.

41L40 is in the McMaster catalog as an easier-to-machine version of 4140
-- I was wondering if (a) it's really easier to machine, and (b) if the
lead interferes with the strength.

I've got a Smithy, and I rarely have trouble machining the "Mystery
metal" that I get for cheap at the local surplus place. Sometimes I have
to take really light cuts, and getting a really dynamite finish is still
a bit of a mystery for me, but I never have _problems_.

--
www.wescottdesign.com