[TheForge] Re: make shift anvil

[Peter Fels And Phoebe Palmer]

Following this line of thought ( that a cold shut absorbs energy).....I 
have a situation that goes like this.
We live on  top of  a very steep lump of clay with some rocks in it. The 
land drops away on 3 sides of us steeper than the angle of repose. On 
one side, we have a sheer scaling face that drops a couple of hundred 
feet, next to it is a very steep slope that falls 750' to the ocean.
Eventually I'll get my power hammer installed but i'm worried about 
jiggling the clay under us too much when it's been soaked by the winter 
rains. If we slide down the hill there is no reason to think we will end 
up on top at the bottom....so...
I've been giving a lot of thought  to the foundation to go under the 
hammer, as you might imagine.
My tentative plan is to dig deep and pour a couple of yards of 
reinforced concrete, put in a layer of timbers topped with another yard 
of concrete. On top of that I plan to stack alternating layers of 
plywood, cork, steel, rubber,  4"wood slab and more timbers.
The theory is that different layers of materials will tend to damp 
different frequencys of vibration and the cold shut effect will be 
compounded by having all those different layers.
It's a lot of extra digging and trouble but I'm spooked about jiggling 
majestically down the mountain side.
Is my plan going to work? Any suggestions/opinions would be 
appreciated......Thanks...Pete F

Mike Spencer wrote:

>>On the issue of force, basic physics dictates that force equals mass
>>x acceleration.  So a heavy hammer at X velocity has greater force
>>than a lighter hammer at the same speed.
>>    
>>
>
>That's not quite right. A mass m at velocity v doesn't "have force".
>
>What it has is both momentum (M) and kinetic energy (KE).
>
>    M = m * v          # Momentun is mass times velocity
>
>   KE = 1/2 * m * v^2  # Kinetic energy is 1/2 of mass times velocity squared
>
>If you swing a small hammer faster, you increase the KE way more than
>you do the M.  And you soon reach the point beyond which you can't
>swing the hammer any faster.
>
>If you "get a bigger hammer", you increase M without having to swing
>the hammer faster.
>
>I'm completely happy with the concept of conservation of energy
>because KE can be converted into some other form of energy, say, heat.
>F'rgzample, when you hammer a cold bar til it's hot, a bunch of your KE
>is turning into heat.
>
>I'm having a bit of trouble with grasping conservation of momentum
>because if there's no v, there's no M.  I see that momentum is
>conserved with bouncy things (perfectly elastic things like steel
>billiard balls or knocking a cold steel pin out of a bushing).  But if
>I hit a piece of lead or clay with my hammer, the hammer stops dead in
>its tracks, the clay or lead moves (mooshes) a bit and stops.  The KE
>is presumably transformed into heat but, since noting is moving,
>there's no momentum.  Huh.  I gotta re-read my physics book again
>because I don't get it.
>
>On one of my MIT trips I had an opportunity to get a physics prof off
>in a corner with paper and pencil and ask him to explain this.  He
>gave a nice lucid explanation of how momentum is conserved in bouncy
>things but kept changing the subject when I asked about hammering
>(nearly) completely in-elastic stuff like clay or lead.  Huh.
>
>On a related note, I think (but can't prove) that the anvil doesn't
>just "absorb" the energy of the blow (as charles said).  Some of the
>energy is absorbed by the (presmably) hot iron and is converted into
>heat.  I think that the rest travels through the anvil as a shockwave
>and bounces (echoes) back against the workpiece while it's still in
>contact with the hammer, thereby amplifying the blow. Cracks in the
>anvil or joints between pieces of junk from which you've made an
>anvil-substitute dissapate the energy of that shockwave and give you a
>dead, less effective blow.
>
>- Mike
>
>  
>