C88 Hammer Position/SPR

[Delwin D Fandrich]

----- Original Message -----
From: "Overs Pianos" <sec@overspianos.com.au>
To: <pianotech@ptg.org>
Sent: November 15, 2001 2:08 PM
Subject: Re: C88 Hammer Position/SPR


> Del and list,
>
> >I'm wondering how you managed to pinpoint the actual mass and/or shape
> >centerline of the hammer that precisely. I'm also wondering how you
managed
> >to control hammer and hammershank whip on impact enough to be sure that
is
> >really where the hammer is striking.
>
> It can be done using a small metal rule, a trouble light (called a
> 'lead light' in Aus - one of the small difficulties we had in Reno
> when we went to purchase one) and a mirror. Mind you, with the small
> radius bars we use the apex of the bar is pretty easy to see - not so
> easy when the radius is larger.

No it can't. You can only determined where the physical tip of the hammer is
striking the string. That is not necessarily the functional center, or the
working center, of the hammer. That could easily be slightly to either side
of the physical tip.

My only point here is that the actual hammer strike point is a somewhat
elusive point which is why all pianos need some method of adjusting the
action slightly after completion.

I used to work with an engineer--the best piano engineer I've known over the
years, now, sadly, retired--who kept reminding me that there wasn't much
point in specifying any tolerance in the piano that was tighter than a
pencil line is wide. True, he spent his career working with hand made
drawings on mylar and not the sophisticated CAD programs we have available
today--but still he had a good point.

Del