[TheForge] sesaw treadle hammer

Thu Feb 13 12:48:01 2003

Uh huh.

I suppose you'd argue a crowbar and a trigger aren't both levers too.

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

Meadow Lakes, AK.

----- Original Message -----
From: "Bruce Freeman" <[email protected]>
To: <[email protected]>
Sent: Thursday, February 13, 2003 3:59 AM
Subject: Re: [TheForge] sesaw treadle hammer

Jerry,

Not really.  Both are dynamic mechanisms and the dynamics are completely
different.  In a compound bow, the force delivered by the string to the
arrow increases in a large step as the arrow is released and the
fletched-end approaches the bow.

The Grasshopper by contrast balances the hammer completely at all points in
the stroke.  This would be equivalent to a bow that delivered NO force to
the arrow.  (Not real useful, that!)

Bruce
NJ

>>> [email protected] 02/13/03 01:19AM >>>
Hmmm. Let me see.

A compound bow uses eccentric pullies to balance pull (arms) and force
(bow).

The Grasshopper hammer uses an eccentric pully to balance weight (pull) and
force (leg)

Same mechanism slightly different purpose.

They're not the same eccentric of course but you wouldn't use the same cam
in a Chevy as you would in your outboard motor either.

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

Meadow Lakes, AK.

----- Original Message -----
From: "Mike Sweany" <[email protected]>
To: <[email protected]>
Sent: Wednesday, February 12, 2003 8:26 AM
Subject: Re: [TheForge] sesaw treadle hammer

>
> Not sure how it's applicaple but just running it through my mind, and well
I'm using my mind so...
>  Bruce Freeman <[email protected]> wrote:Not sure how the compound bow
mechanism would help. A compound bow delivers a strong pull through most of
its stroke, but only a weak one at full extension   where you have to hold
the arrow to aim. How is that applicable to a treadle hammer?
>
> The Grasshopper uses an eccentric pulley - effectively a continuously
changing lever arm - to balance the continuously changing force of the
spring with the (surprise!) continuously changing torque of the ram. Yes,
the torque of the ram changes as the arm changes angle.
>
> (If instead, you put the ram on rollers or sliders and hang it from a
cable above, then there is no torque per se, and the weight of the ram is
unchanging. Get a strong equal-force spring and you're home free.
Unfortunately equal-force springs are typically quite weak.)
>
> Good luck,
>
> Bruce
> NJ
>
> >>> [email protected] 02/11/03 02:08PM >>>
>
> Bruce, hmm maybe a self contained weightless ram.
> Been thinking, and darn I know it is dangerous, but that never stopped me
before.
> Wondering about the compound bow mechanism anybody played with that one??
> too nice a day to be inside (BIG LONGING SIGH)
>
> Bruce Freeman wrote:Mike,
>
> Between the speed and the pine test, it sounds like you've pretty much
confirmed my observations from 1998.
>
> You could skip the see-saw mechanism, and simply balance the ram by a
means similar to that used in the Weightless Eammer. I suspect the mechanism
used in the Grasshopper Treadle Hammer might also work, but that was
calculated for a slightly different mechanism than a swing-arm hammer, so
I'm not sure.
>
> Bruce
> NJ
>
> >>> [email protected] 02/10/03 01:51PM >>>
>
> Well it belongs to a friend of mine I'm guessing a at a 10,15lb head and
maybe twice that or a bit more on the back side.
> he kinda just stuck it together, had to beef up the arm, 1-1/2" pipe, (it
kept bending)
> We stuck a piece of pine in it and stepped on the pedal. it would compress
the pine about what you'd expect from swinging a ten lb without a lot of
oomph behind it.
> DragonsWatch wrote:Hi Mike,
> What is the total weight of your ram/counter weight? Do you figure you are
getting a comparable blow to another TH with the same weight?
> Inquiring minds want to know :-)
>
> Thanks,
> Larry
>
> Mike Sweany wrote:
>
> > I did see a sesaw/counterweight style treadle hammer last weekend .
> >
> > Upright, hammer arm was mounted at and angle to the upright, bush down
on treadle, whack. Counterbalance returns the hammer head for the next blow.
> >
> > Not fast not elegant but it will sure deliver a good whack. the anvil
was adjustable in height to maintain a square blow .
> >
> >
> >
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