bechstein

[David Ilvedson]

Ric,

I did the numbers again:

		R
#1	        6.0
#2		5.8
#9		5.9
#10		6.0
#16		5.4
#17		5.8
#28		5.7
#29		5.7
#40		5.5
#41		5.6
#52		5.7
#53		6.0
#64		5.7
#65		5.3
#76		5.6
#77		6.1
#87		5.5
#88		5.3

Averages out to 5.7

Looks like the bass needs the balance rail shimming...17 note bass.

Is a higher Key ratio mean better or worse leverage?    5.5 vs 6.0

David Ilvedson, RPT
Pacifica, CA  94044


----- Original message ----------------------------------------
From: "Ric Brekne" <ricbrek at broadpark.no>
To: pianotech at ptg.org
Received: 8/7/2006 4:43:11 PM
Subject: bechstein


>Hi again David

>The 4-3-2 / 3-2-1  etc are leading patterns and in general the more lead 
>peices you put in the heavier your FW's.  In the last few years Stanwood 
>has developed his pattern leading to roughly relate to various FW curve 
>levels.  The pattern leading distibutes key mass more evenly so as to 
>allow for both an even FW (static) curve and a more even key to key 
>inertia which gets into dynamic key <<weight>>.

>I dont have his primer book so I cant reference it... but a 5.7 ratio 
>with a SW8 or 9 curve generally points to reasonably close to maximum FW 
>levels (depending on what BW you are specifying of course.)  I believe 
>he also operates with a 5-4-3-2 pattern.

>If you havent already down so... review the see-saw science 
><http://www.stanwoodpiano.com/seesaw.pdf> side at his website.  Put this 
>stuff into perspective with his balance equation and experiement with an 
>action model til you get it figured out.  Keep it basic for now.

>Cheers
>RicB



>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