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Posted by Carl West on July 11, 2008, 11:37 am
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When Tozetre put fingers to keys it was 7/11/08 8:38 AM...
> Short answer; nope, the formula for calculating the force that's going
> into hot iron is; energy = (how heavy the hammer is) times (how fast
> it's going).
Having just gone back to that wiki page of formulae it looks like we
want to be talking about Kinetic Energy, Work, and Power
(ignoring gravitational potential energy)
KE = 1/2 x m x v^2
W = /_KE (trying to make a 'delta')
P(avg) = Work / /_Time
So, getting the hammer going twice as fast does quadruple the Kinetic
Energy of the blow, which quadruples Work and approximately quadruples
Power (I'm sure contact Time increases slightly for a heavier blow. How
much? no clue).
>> Also, if the hammer bounces, it must be
>> decelerated and then re-accelerated in the opposite direction - more force.
>
> Nope. The amount of force available doesn't change, just where it goes
> and what its direction is.
If it doesn't bounce, that means all the energy has left the hammer and
gone into the piece (for practical values of 'all'). It it bounces, it's
carrying some energy away with it.
The colder the work, the more the hammer bounces, the less energy
imparted to the work, the less it is deformed. Hmmm...
--
Carl West
http://prospecthillforge.com : The Blacksmithing Classroom
Reduce. Reuse. Recover. Refurbish. Repair. Repurpose. Recycle.
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