[TheForge] Re: make shift anvil

Sat Oct 18 19:59:01 2003

Having seen pics of your property I understand your concerns, the hills of
coastal california aren't that stable under without adding man made
vibration. Talking to a soils engineer might be the best route to peace of
mind, a foundaton can be designed for almost any soil condition.

I just deleted about two pages of ramblings of what I remembered about
plastic and liquid limits of soils. Rereading them drove home just how long
it's been since I was a lab rat in the state soils lab. We dealt with it
daily while I was drilling but while I can look at soil, play with it a
little and make a decisio I'd be comfortable with is a LONG stretch from
describing a how to on even field checking your soils.

There are a couple rules of thumb I can pass on though. You have two factors
affecting your soil stability moisture content and movement. Well, there are
more of course but these are the ones you're concerned with if you have
plastic soils which most clays are.

Your first line of defense will be to keep as much water out of the soil as
possible. Making sure your land is as well drained as possible or practical
is the first step, this means drainage ditches with outlets well below your
area of effect. Another real easy if not cheap method is to pave as much as
reasonable, asphalt pavement isn't waterproof but it's good at channelizing
water at the surface.

Minimizing the vibration from your hammer is your second main line of
defense. A foundation structure that will dampen or even eliminate ground
vibration can certainly be designed but you'll need more expertise than I
can bring to the discussion. If I didn't have expert advise available I'd
use what I know works. Piles. I'd have a "H" or can pile driven well beyond
the saturation depth or into bedrock if it's a reasonable depth. I'd put one
directly under the hammer and incorporate it into the hammer foundation.

Subexcavating the foundation and laying a couple feet of crushed rock with a
drain would PROBABLY be sufficient however. Crushed rock keys together on
the broken faces so tends to stay put making a good solid foundation.
Vibrations don't tend to travel well through gravels so such a foundation
would damp at least most of the hammer's vibration. If I was going this
route I'd make the gravel bed at least a foot wider on all sides and at
least two deep. I'd lay a sheet of cardboard, Typar, etc. on the well
compacted gravel to isolate it when I poured the reinforced concrete
foundation pad.

Well, it's still a kinda long ramble but not near so bad as the part I
deleted. <grin>

Frosty
------------------------
If it ain't forged
it ain't real.
Wrought iron is.
The FrostWorks

Meadow Lakes, AK.

----- Original Message -----
From: "Peter Fels And Phoebe Palmer" <[email protected]>
To: <[email protected]>
Sent: Saturday, October 18, 2003 12:12 AM
Subject: Re: [TheForge] Re: make shift anvil

> 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
> >
> >
> >
>
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