Renner "Turbo Wippens" ?

[David ilvedson]

Bill,

I'm with you...I always want DW & UW, what good is one without 
the other.  I guess I'm still not sure of the value of BW and 
will continue to look into it.  Thanks for the reply!

David ilvedson, RPT
Pacifica, CA



> Date:          Mon, 12 Oct 1998 14:16:53 -0400
> To:            pianotech@ptg.org
> From:          Bill Ballard <yardbird@sover.net>
> Subject:       Re:  Renner "Turbo Wippens" ?
> Cc:            pianotech@ptg.org
> Reply-to:      pianotech@ptg.org

> At 9:28 AM +0000 10/12/98, David ilvedson wrote:
> >BW=(DW + UW)/2...What does that show us?  I am not particularly
> >up on Stanwood's "balance weight" work.  Was there a recent
> >article in the Journal I missed?  With a 50 gram DW and a 25
> >gram UW we have 37.5 BW which I would assume is a good balance
> >weight?  With a 60 gram DW and a 30 gram UW we would have a 45
> >gram BW.  A 60 DW and 20 UW would be 40 BW.
> >
> >Thanks in advance...
> 
> You've got the math right. The Balance Weight concept was the first element
> in David's extremely useful system of action analysis (or as he puts it,
> "metrology). Actually the concept had popped up once or twice before in the
> PTJ before he proposed his ideas in the 11/90 PTJ.
> 
> The essential assumption is that if the resistence which we read at the
> keyfront with gram weights were 100% mass related and 0% friction, the DW
> would equal UW. As friction grows (and by varying accounts it should run
> 16g @ #1 to 10g @ #88) the DW and UW should spread apart from each other
> symetrically. The reason  for this assumption is that we need some way of
> separating mass and friction in our diagnosis and treatment of action
> problems. This may be a crude assumption, but the alternatives are either
> nothing or rocket science.
> 
> BW is the first step in a very carefully structured analysis, which has
> been well documented by David, both in the PTJ and at Convention Classes.
> As for me, don't give me a DW or an UW. Give me both: I'll convert them to
> mass and friction figures and be on my way.
> 
> Bill Ballard, RPT
> New Hampshire Chapter, PTG
> 
> "No one builds the *perfect* piano, you can only remove the obstacles to
> that perfection during the building."    ...........LaRoy Edwards
> 
> 
> 
> 
> 
David Ilvedson, RPT
Pacifica, CA
ilvey@jps.net