[TheForge] Little Giant / pulley / rpm / ???

[Bruce .]

Mike,
Your measurement might be fine, but when measuring a spring constant isn't
feasible, it turns out that you can measure the spring dimensions ("wire"
gauge, OD/ID, and maybe pitch) and calculate the spring constant.  Don't
ask me how, but I think it's in the Machinery's Handbook.  In principal,
this also depends upon the steel, but in practice it seems not so much.
For extension springs (which I was mucking about with), there an additional
complication of pre-stress, when the coils are tight together when
"relaxed" (i.e., it really isn't relaxed) and it takes force to spread them
at all.
This info went out of my head a decade ago when I no longer needed it ...

Bruce
NJ

On Sat, Mar 21, 2015 at 4:31 PM, Mike Spencer <mspencer at tallships.ca> wrote:

>
> Larry Brown wrote:
>
> > I was working on one that someone had stepped down and when I
> > eliminated the jack shaft and got a new spring it changed it
> > remarkably.
>
> Did he ever mention -- has anyone mentioned -- a numerical spring
> constant for LG/Jardine hammer springs?
>
> It's a heavy spring so you can't just compress it with a handy weight
> and measure deflection with a rulera.  But I rigged up an arrangement
> with a 65# weight at the end of a 4' lever and measured the deflection
> with a dial indicator. I got 2149 lbs/in on both the installed spring
> and a spare.  Another spring that came with the hammer but may not be
> an actual LG product was 2016 lbs/in.
>
>
> - Mike
>
> --
> Michael Spencer                  Nova Scotia, Canada       .~.
>                                                            /V\
> mspencer at tallships.ca                                     /( )\
> http://home.tallships.ca/mspencer/                        ^^-^^
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