[TheForge] Re: make shift anvil

Sat Oct 18 08:23:00 2003

        Morning Pete,  I have a couple points to make on the ground
response. I'm no expert by any means on earthology, but I know what I've
seen in the past.
         Doing a lot of work with excavators in the past I see them use (and
have built) many "bog floats"  The ground pressure of a track machine is
very spread out to begin with, but when a "float" is set beneath one
..........it is amazing where a machine can go.......it can literally cross
a swamp!
        The "bog floats" were 40' timbers sawn at a local mill I helped set
up for making these units up.  They were bolted to gether with long rods to
help keep them together as a mat and a lifting eye of sorts usually a cable
wrapped around 4-6 of the beams - for moving one infront of the other to do
your work/crossing/ or basicly get where you had to get to do what you had
to do.  This spreading the load further out on the mucky, soft, water laden
soil or clay surface had good results.
        When ever the machine would work to one side.......the floats would
eventually start to settle in towards that side and you'd see the water
scooch out from below.  You see the same thing when you try to run a
compactor over an area of wet clay on a construction site.  The machine
tends to bog down and the water and mud comes from the loose side of the
soil and the machine tilts to bury itself towards the uncompacted side that
was the most loose to begin with.
        So to remedy this sinking to the side and the water/muck sinking
something pounding on it from above.........crushed rock was placed into the
material and when enough crushed rock is added......you create a jagged
interlocked base that makes a pad of concrete like hardness on top, and the
facets of the rock spread the load in different directions and it becomes
extremely firm and stable.

        My approach to your project from what I've seen in the past - would
be to dig the hole and use crushed rock(well driven into the clay while
wetting it down, then put a wood bunk platform for distributing the load
evenly across this whole affected area of where the hammer will be mounted.
Now the hammer I would also put on a thick steel plate to further spread the
load evenly and not allow the anvil to work on a particular area of the
bunks.  I'd also take something like a 2" maple layer and a 7 ply conveyor
belt to protect the rough casting against the steel plate.
        If you have the pitch and can add a drainage to the crushed rock
below......it would get rid of the water in the clay beneath the crushed
rock as it came up(similar to the water rising out of concrete when being
worked).

        I've seen hammers set on clay or (grainy) sand as I'd call it. They
were mounted to concrete bases and tended to roll towards the front as the
hammer struck over the years and settled it into a forward lean.  I
therefore would also make the hammer location be central from the anvil in
reguards to the crushed rock layer/ wood bunk platform/ steel
plate/maple/rubber/and then anvil.
        Mabe adding some filter fabric just before you do the crushed rock
would allow a longer drainage from the rock as it wouldn't fill with clay
fines as fast over the years.

        That's just my guess as to how I'd approach it.

Ralph

----- Original Message -----
From: "Peter Fels And Phoebe Palmer" <[email protected]>
To: <[email protected]>
Sent: Saturday, October 18, 2003 4:12 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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