Touchweight Metrology Question

[David Love]

Bill:

I'm not sure I would agree with your assessment of putting 18mm shanks on
this piano.  The SWR for the naturals is already 5.5 on average (some are
even lower if the measurements are correct).  If he puts on an 18 mm shank
it will lower the ratio to under 5.  That's too low and will create some
regulation problems.   The BW's are erratic because the KR is different
between the sharps and the naturals (.50 and .48 respectively).  This has
created a different ratio between the sharps and naturals and has resulted
in erratic balance weights even with a relatively smooth SW pattern.

David Love



----- Original Message -----
From: "Bill Ballard" <yardbird@pop.vermontel.net>
To: <pianotech@ptg.org>
Sent: May 16, 2002 10:13 PM
Subject: Re: Touchweight Metrology Question


> Terry,
>
> It's pretty clear what you have. Like RicB says, you've got plenty of
> had room in the FWs to drop the BWs. I've sent plenty of CBS Teflon
> Steinways with this same initial set-up. They left the BWs high in
> order to keep the FWs, although by current standards, they had could
> move the BWs quite a bit before getting into trouble with the FWs.
> Legend has it that their DW measurements were confused by the initial
> stickiness of teflon friction. BTWs still leave a noticeably high BW
> (lo-40s instead of mid-30s).
>
> The SWs are medium in the bottom third, medium heavy in the middle
> third and light in the top third. You say you've got plenty of stock
> for removal, on these OEM hammers. But the problem is not your SWs
> but the 16.5 knuckle mounting distance (KC).
>
> But the current SBWs, although erratic, are still quite reasonable
> even with the 16.5mm shanks. That is thanks to the KR. I'd say (based
> on a sample of 12/88) that the keyboard is well laid out, and at the
> very least a big advantage. (It saves you one whole area of work.)
> Put 18mm shanks on here and you'd be able to  lower the BWs without
> demanding too much weight loss in the hammers, just cleaning them up.
> That is, assuming there is room to get a satisfactory balance of blow
> to dip.
>
> At 8:43 PM -0400 5/16/02, Farrell wrote:
> >I think I also need to regulate out a few notes to be sure that the
> >current geometry is not requiring excessive dip.
>
> What I was referring to, except here to confirm a "before".
>
> At 8:43 PM -0400 5/16/02, Farrell wrote:
> >I should point out here that this piano is in a small church, and it
> >seems that the piano is not a high priority for spending money - so
> >I'm probably not going to get to do everything I might want.
>
> So what would you like to do on this job, do an SW/FW/Shankchange on
> your nickel, or a good solid friction control (shank repin, keypin
> fit & lube), action regulation and voicing which you've sold to them?
> Tough choice.
>
> I'd say start with the basics, and see how much the piano gains from
> that (and how that improvement fits the needs of the Church). But
> know from the analysis at the outside what the action's basic profile
> is, "how it's hung", and what that area of the action's set-up would
> require.
>
> At 8:43 PM -0400 5/16/02, Farrell wrote:
> >Not having seen all this data before, it seems rather erratic to me.
> >How in the world can the BWs range from 49.0 to 60.5? And that is
> >with a very smooth SW. I assume this is mostly erratic leading?
>
> It's an indication of what they were reading, and it does look a
> little funny from this standpoint.
>
> Bill Ballard RPT
> NH Chapter, P.T.G.
>
> "Lady, this piano is what it is, I am what I am, and you are what you are"
>      ...........From a recurring nightmare.
> +++++++++++++++++++++
>