action ratios

[David Love]

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Dale Erwin wrote:

... For example many of the Stwy actions I (we)work on from the  glory =
years (The 20's) require no more than a minor knuckle movement (16 to =
16.5 mm) to accommodate a slightly heavier hammer and stay within the =
normal regulation ranges ...


The problem with Steinways is that the key ratio can vary considerably, =
from .48 to .56.  That makes the selection of knuckle placements more =
problematic and often requires a move of the capstan as well.  In =
general you can figure on a .4 change in the action ratio for each 1 mm =
change in the knuckle.  So it's very important to understand the overall =
action ratio when making changes and then target a specific hammer =
weight (strike weight) to match up with it.  There are times when the =
original setup .48 key ratio and 16 mm knuckle will be delivering a low =
enough ratio to accommodate a 1/2 - 3/4 medium zone hammer (a typical =
new Steinway hammer with taper).  However, there will be a different =
friction component with a knuckle at 16 mm than at 17mm and it is often =
worth considering moving the capstan so that you can use a 17mm knuckle =
in order to keep friction lower.  The magic line, of course, should also =
be considered.  On a Steinway I find I generally like to use key ratio =
.52 - .53 with a 17 mm knuckle.

David Love
  ----- Original Message -----=20
  From: Erwinspiano@aol.com=20
  To: pianotech@ptg.org=20
  Sent: November 03, 2002 12:29 PM
  Subject: Re: action ratios


  In a message dated 11/3/2002 11:32:27 AM Pacific Standard Time, =
davidlovepianos@earthlink.net writes:





    I am still strongly inclined toward setting up actions with great
    consideration given to determining an action ratio that will give =
proper
    regulation specs.  If there is a desire to use hammers whose weights =
fall
    outside of the boundaries that allow for a good match of weight to =
leverage,
    then other solutions, or compromises will have to be considered.  =
For 99% of
    the actions I do, that seems unnecessary.  For that other 1%, assist =
springs
    seem to be the most reasonable solution.

    David Love


               David and all
                I wholeheartedly agree. I find that when regulation =
parameters are compromised that should be a screaming indication that =
something is not right. I.E. Sample regulation notes are such a good =
indicator of potential problems with weight and inertia and deciding how =
to rectify them and still stay within some fairly reasonable hammer =
weights (strike weight if you prefer that term). Touch weight in terms =
of inertia and leading or possible unleading decisions can often quite =
easily be seen at this early stage of analysis. Although resolving some =
action and key deficiencies can be complex and may require more in depth =
analysis many are resolved by these simple diagnostic tools early in the =
process.=20
       For example many of the Stwy actions I (we)work on from the  =
glory years (The 20's) require no more than a minor knuckle movement (16 =
to 16.5 mm) to accommodate a slightly heavier hammer and stay within the =
normal regulation ranges of  .390 ish dip and 1 3/4 blow distance. It's =
also easily possible to stay within the reasonable inertia ranges and =
often the original pattern leading is sufficient and uniform enough to =
retain or shift only slightly. This is important as not many clients =
will know or appreciate the difference of, or be able to utilize a =
completely a microscopically balanced action. There are practical =
financial considerations to the client for all of this tweaking and =
microscopic adjustment after all and this is a real life consideration.
     For the action, technician or pianist desiring the micro-balanced =
action I'm finding it a whole lot more effective and efficient, all be =
it more expensive, to design the action and key ratios together by =
having a new key set made. Roseland makes affordable key sets and sooo =
many or the old actions frankly have been recovered, resoled , rebushed, =
and yes even repainted to the point of necessary replacement that it =
only makes sense to go in this direction. Oh also I left out  just awful =
original geometry that moving the capstan, etc., will not fix.
     I  think that this whole idea of "Component Action Balancing" Terry =
F.'s term, is a fabulous tool No modern technician would be without but =
there are differing levels which it can be applied and my point is to =
"Point that out" to prevent less indoctrinated or experienced brethren =
on the list to be overwhelmed by the whole discussion of action =
balancing and simply throw up there hands saying I'll never be able to =
sell my clients all that so why try.
     As Bill Spurlock has often said "many people were moved to tears, =
goose bumps, etc., by many of these pianos" when they were new, which =
doesn't mean they were as refined as we know they can be now  but it's =
important to strive to do consistent basic piano work first and add the =
more technical type skills as fast as one can. In concluding  Bill has =
also often said"It isn't necessary to reinvent every action for every =
client" even though I'd personally like to. Does that make sense to any =
body else.
     Just my view >Dale Erwin


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