"skuke" wrote in message
...
On Wed, 05 Jan 2005 03:02:21 GMT, Dixon wrote:

"skuke" wrote in message
...
On Wed, 05 Jan 2005 00:37:15 GMT, Gunner wrote:



Ive had some experience with the SEAL titanium knives and while they
are definately anti-magnetic (for mine clearing and so forth), and
they can be heat treated to some rigidity..they dont sharpen well, or
stay sharp.

Gunner



I thought heat treating affected hardness, not rigidity (modulus of
elasticity)????
--
Skuke
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Congrats Skuke, don't see many people who know about hardness not
affecting
ridgidity, including my college machine shop teacher.
Dixon


Thanks. I, the machinist, have had to explain this to more than a few
mechanical engineers at work :-(


I do have a question regarding all the comments about the Ti sword being
too
light to be effective. Where is my error in the following?

Let's say Barry Bonds picks up a 30 pound steel sword to swing at the ump
who mis-called a strike. He swings it at 10m/sec. Using the formula: .5
x
30lb x 10^2 = 1500 joules.

I'm sure he swings much faster, but the numbers make for easy math.
Anyhow,
if instead he picked up a 20lb Ti sword (roughly 1/3 lighter weight than
the
steel one) and swung at *only* 2.25m/sec faster (12.25m/sec), he'd have
about the same amount of kinetic energy releases. So, any amount he could
swing faster than 12.25m/sec would yield more energy and greater damage.
Right??? Is my error that it is impossible to increase the speed by 20%

I figure this is the reason why cheaters cork their bats rather than lead
their bats. Of course, I'm not implying that Barry uses a corked (or
steroid laden) bat. ...Or would ever attempt to hit the ump...
--
Skuke
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First, you're dead right, there are engineers I've known who aren't aware --
or more likely forgot -- that the stiffness of any piece of steel (of
regular steel alloys that is, not including stainless) is essentially the
same. Hardness and strength have no significant relationship to it.

As for your baseball problem, you may be dealing with momentum rather than
energy. Maybe. That relationship always gives me trouble. People who deal
with firearms ballistics, such as Gunner, have a better handle on it.

--
Ed Huntress