bechstein

[David Ilvedson]

Thanks Ric,

I might take you up off line...so I'm looking at my "Little Stanwood Primer Book" at Appendix A...touch weight parameters table.   Not sure what the 3-2-1 compared to the 4-3-2 means other than more lead in the keys?   The 4-3-2 shows my 5.7 will get me in SW8 or 9 curve..right?   

I'm going through the measuring again and doing the partial sample set this time...just to make sure what I've got.   I've gone over the friction issues and now #16 is way different...D=43 U=17...too much lead for that key...5  3/8" leads...BW is 30...way to low...so if I can get it up to D=55 and U=23, I'll have BW=38...
You mentioned getting my BW down and I think I understand that now.   Too much downweight and too much upweight...in general...heavier hammers will take care of some of that and FW changes will do the rest...?   I think...

David Ilvedson, RPT
Pacifica, CA  94044


----- Original message ----------------------------------------
From: "Ric Brekne" <ricbrek at broadpark.no>
To: pianotech at ptg.org
Received: 8/7/2006 3:55:21 PM
Subject: bechstein


>Hi David
> 
>I mean that with a 5.7 ratio you could easily handle a bit heavier 
>hammers.  You see, for a specified 38 BW a 5.7 ratio matches very well 
>with a top medium strikeweight curve. This assumes a 9 gram WBW ... ie. 
>(KR * WRW). Yours is closer to 10 but thats not enough to make a big 
>enough difference to worry about for now.  With these givens (ratio, 
>wbw, and BW) you can match Strike weights to Front weights and the trick 
>is to end up at or below what is recommended as maximums for FW's.  What 
>actually should be maximums for FW's gets a bit subjective... but for 
>the sake of learning your Stanwood ropes just accept his table of 
>maximums.  With a 5.7 ratio, 38 gram BW spec, 10 gram WBW and going all 
>the way to the maximum FW's you can still handle a top medium curve 
>nicely.  Heavier hammers then that will require too much FW or 
>combination of FW and assist springs.  Essentially... you dont have 
>enough levearge to use a heavier SW curve then top mediums with these specs.

>Takes a bit of practice... but if you work with Stanwoods formula and 
>his charts very much eventually becomes clear enough.  Alternatively... 
>you can do as many will suggest and go with a lower SW curve... such as 
>your exisiting one.  That will allow you to counter balance with FW's 
>well below the suggested maximums and still get a reasonably low BW.. 38 
>for example. This is attractive to those amoung us who believe much 
>lower mass levels in the keys is a desirable. 

>One immediatly will move into a more complicated series of questions 
>about mass levels in keys and its effect on play... but at your stage I 
>would suggest getting the basics of Stanwoods Balance methodology down 
>and understood. In its simplest form, I like to think of his method as a 
>very precise way of doing the weigh off process... one that utilizes 
>very even SW values key to key as a starting point.  Learn how to 
>balance a SW curve with an existing ratio first... then move on to 
>bigger and better things if you get my meaning.

>I can offer you a walk through with your action off list if you like, 
>but only as much as Stanwoods patent allows for.  Essentially that means 
>you can not install FW's figured with his balance equation.  You can 
>figure them for the sake of learning... but you will have to install 
>FW's established a different way. And there are some good alternatives 
>given an even SW curve and a known ratio as a starting point.

>Cheers
>RicB





>New parts will help the friction problems.   I'm still foggy on this 
>whole thing...you say the 5.7 ration is doable but I could go up a 
>notch...that means 5.8 or 5.6?   I'm looking at a 1/4 or 1/2 medium 
>hammer weight curve, right?   Do I follow the hammer curve before I hang 
>the hammers...HW...seems easier without the shank in the way?   I have 
>been reading through the archives and I feel like Terry Farrell back in 
>2002 when he was trying to learn this stuff...   

>David Ilvedson, RPT
>Pacifica, CA  94044