[TheForge] Re: TheForge digest, Vol 4 #694 - 14 msgs

[Thomas A. Troszak]

> From: GHS <ghs@execpc.com>
> Subject: Re: [TheForge] hammer vibration continued

> Tom, before you answer let me put my foot in my mouth and see if I have
> the principle down.
> 
> The greater the ratio of the anvil to the hammer the less the vibration.
> 
> Mike Graf
> 
> gladish wrote:
>> So, Tom, let's follow this line of reasoning; if a big steel plate under a
>> hammer absorbs the vibration (at least the portion of the vibration that is
>> obnoxious to neighbors), does that mean that a cast hammer (heavier) makes
>> less of that vibration to begin with and that a fabricated hammer (usually
>> lighter) is more likely to be annoying?
>> What if Shanxi were to make a 4000# 40 kg hammer for the US small shop
>> market- would it need no pad at all except for stabilization?
>> That agrees with my observations, by the way- the worst was a Turkish hammer
>> (not a Sahinler- the other one) with an undersized anvil, the mildest was a
>> big Nazel being run fairly lightly on 1" stock.
>> Andy G.
>> 


Dear Mike,
Yes.

Dear Andy,

The cast iron (self contained) hammers may be heavier overall than some of
the fabricated (self contained) ones, but the noise of operation, and
vibration in the earth are two separate phenomena.

Extra mass in the FRAME of any hammer will NOT help the hammer hit more
efficiently, or keep the glasses on the shelves, but it tends to make the
hammer quieter overall.  I have heard some of the fabricated hammers that
were incredibly annoying because of all that sheet metal flappin' and
clangin' with every stinkin' blow.

Extra mass in the ANVIL of any hammer will definitely cut down on the amount
of pounding in the floor, and the hammer will hit more effectively, but may
not make the hammer quieter overall.

From what I have seen, most of the fabricated self-contained hammers have
pretty pathetically small anvils, 'nuff said.

I can't comment on the new Chines jobs, cause I haven't seen one yet. Even
if they made the whole thing weigh 10,000 lb., it would be less aurally
annoying, yes, but it still won't help the vibration issue unless most of
that mass is in the anvil, period. Remember that an anvil is a mass floating
in space, so even if you have a huge mass, but you are pounding out at the
very end, the whole mass is just going to try to rotate about the CG, so the
front would tend to tip down over time, and the extra mass at the rear of
the hammer isn't going to prevent this.

So your generalization would be generally true, sort of.

Sorry I missed your question, I get the pre-digested list, and sometimes
can't make heads or tails of it.  If you ever ask a question and I don't
answer in about three days, please just ask again, I just missed it.

Clear as mud?

Tom Troszak