On Sun, 01 Apr 2001, "David Love" <davidlovepianos@hotmail.com> wrote:
>The "feel" of the original configuration was difficult to determine
>because of the verdigris.
For future reference: a quick application of Protek will remove
vertisgris' interference with these judgments.
> I have begun to play with David Stanwood's ideas over the past year
>and this has been a crash course. The relationships between all his
>variables is still something I am working on understanding.
His ideas are much simpler than most would suspect. The variables
amount to measurements of weight and leverage of individual
components or combinations thereof up to and including the overall
leverage ratio (Strike Balance Ratio, the ratio of the hammer weight
out at the end of the shank and how that weight is perceived, by
judicious taring, at the key front). His crucial innovation is to
approach touch resistance within the dimension of mass rather than
distance (ie., the length of lever arms). A long-overdue innovation,
IMHO.
>At the moment I am leaning toward further reducing the strike weight
>by thinning the hammers and possibly going to a 17mm knuckle.
Alot simpler than moving the cap line or springing (no pun intended)
for turbo reps.
>I am not that happy about the regulation compromise, but I am double
>checking my samples to be sure that my original regulation specs are
>correct. If I can keep the dip under .400 and the blow not less
>than 1 11/16 and remove a bunch of lead, I think it will be adequate
>for now.
Look at the isue this way. If the situation forced you to choose
between an action regulated at 1-3/4 and .390 but requiring excess
lead and one whose FWs were where they belonged but which regulated
at .410" and 1-3/4, which action would your pianist like better? Not
that, with your skill and thoughtfulness, you're being boxed into
such an either/or.
>>Ron Overs <sec@overspianos.com.au> wrote:
>>
>>If David were to reposition the capstans as Bill suggested, he may
>>still be able to get the hammer/key ratios he's looking for without
>>changing to 17 mm shanks.
Actually if he is willing to move the cap line (with possible
corresponding movement in the rep heels), he could make a 15.5mm
shank work. Little difference it makes whether you have a 15.5mm
shank with a .47 key ratio or a 17mm shank and a .55 key ratio, each
combination will produce a similar package of blow/dip and FW/BW. The
only way around this is to counterbalance the weight of the hammers
not with lead but with helper springs.
>>The use of excessive amounts of lead to get the required DW
>>is a sure sign that there's something wrong with the basic geometry
>>(assuming that all of the usual suspects, centre pin, bushing and
>>balance pin friction have been checked).
Speaking with great respect for your accomplishments and a piano
technician and now piano manufacturer, if the situation can be
described in terms of Balance Weight instead of DW, we can explore
weight and leverage as separate from friction. Divide and conquer.
All said and heard, David, I'd rehang with 17mm shanks. By the end of
the job you'll be much happier.
Bill Ballard RPT
NH Chapter, P.T.G.
"Filing the bridgepins sure puts a sparkle on the restringing, but is
best done before the plate is re-installed"
...........recent shop journal entry
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