[TheForge] rigid vs. springy steel

[William Bohl]

Steel is steel for stiffness, springiness, flex or whatever.  Not many
metals are better - beryllium and tungsten come to mind.  You do want a
steel you can harden so that you can pry harder before it yields and takes a
permanent set with a bent shape.  Just don't make so hard that it snaps
instead of bends (ouch).  Thicken until you get to the stiffness that you
need.  Adding width will help to a lesser degree.

Bill

-----Original Message-----
From: theforge-bounces at mailman.qth.net
[mailto:theforge-bounces at mailman.qth.net] On Behalf Of Bruce .
Sent: Thursday, July 25, 2013 3:06 AM
To: Blacksmithing List Sponsored by ABANA
Subject: [TheForge] rigid vs. springy steel

Here's a question you metal munchers might be able to field:

I have had a few applications in which I need thin but rigid steel.
What steel is best?

Consider for example a corkscrew -- it's a helix that holds its shape, it's
rigid.  But a spring with a comparable shape is flexible.  What's the
difference?  I suspect that it's simply the relative dimensions -- a spring
is relatively thinner wire wrapped on a relatively larger mandrel, and
vise-verse the corkscrew.

But is that all there is too it, or is there a metallurgical difference as
well?

Although I've contemplated making corkscrews, the immediate application is a
prybar for roofing and siding nails and similar stuff.  It would be flat,
like these:
http://www.homedepot.com/p/Dasco-Pro-Pry-Bar-Set-3-Piece-91/202585548#.UfDoy
m1cWgw
but of thinner steel.  (If I can't make it thinner, I'll just use a
commercial one.)

I'd like it as thin as possible for a number of reasons, but I don't want
more than minimal flex to the thing.  So I'm wondering what steel to use.

I have, BTW, considered using thin steel and putting longitudinal bends
("ribs" or "nerves" or "corrugations" -- whatever you want to call them --
as are used in larger HVAC ducts to prevent oilcanning of the large flats)
in it, but this partially defeats the purpose, as the result would
effectively be thicker -- so why not use thicker metal and be done with it?

This is not any sort of critical problem, but I've had similar problems
before and left them unaddressed.  This time I thought I'd ask....

--
Bruce
NJ
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