Touchweight Metrology Question

[Roger Jolly]

Hi Terry,
             Is this action working with about 3/8" or less dip?
Roger


At 08:43 PM 5/16/02 -0400, you wrote:
>Well, I'm trying to plug along here with my Yamaha G5 heavy action. Below
is a table of my data for ten sample notes (I hope it comes through
un-screwed up). I think all is fairly self explanatory perhaps except for
the last four columns. FWC is Front Weight Ceilings (from Stanwood data
tables). FWT is Front Weight Targets, which is the FWC, less 10% (safety
factor). BWC is Balance Weight achievable with using the ceiling FWs. BWT
is Balance Weight achievable with using the target FWs.
>
>#    DW  UW   F      BW     FW     KR    WW    KC     SW    R    FWT  FWC
BWT BWC
>16   61   37  12.0   49.0   29.0   0.49   18.4   16.5   11.9   5.8   33.8
 37.5   44   41
>17   67   39  14.0   53.0   30.3   0.49   19.4   16.5   11.9   6.2   33.5
 37.2   50   46
>28   59   38  10.5   48.5   23.1   0.48   18.9   16.5   11.3   5.5   30.6
 34.0   41   38
>29   73   48  12.5   60.5   17.7   0.50   19.1   16.5   11.2   6.1   30.3
 33.7   48   45
>40   67   40  13.5   53.5   14.1   0.48   19.7   16.5   10.5   5.5   27.0
 30.0   41   38
>41   72   46  13.0   59.0   13.5   0.50   18.5   16.5   10.4   6.1   26.6
 29.6   46   43
>52   66   47    9.5   56.5     3.6    0.48   18.6   16.5     9.6   5.3
22.6   25.1   38   35
>53   68   46  11.0   57.0     8.0    0.50   18.4   16.5     9.5   5.9
22.2   24.7   43   40
>64   62   41  10.5   51.5     2.6    0.48   19.3   16.5     8.3   5.4
17.2   19.1   37   35
>65   63   41  11.0   52.0     6.7    0.50   19.0   16.5     8.3   5.9
16.7   18.6   42   40
>76   59   41    9.0   50.0    -1.7    0.48   18.3   16.5     7.3   5.4
10.4   11.6   38   37
>77   62   42  10.0   52.0    -0.3    0.50   18.8   16.5     7.1   6.0
9.9   11.0   42   41
>  
>Action spread is right on the money at 112.5 mm.
>
>My SWs are right along the divide between medium and heavy hammers on the
smart chart. I should think this is a reasonable weight set of hammers. I
see someone forgot to put lead in the keys along the line somewhere! But I
also see that even if I go right up to the FW ceiling, I will be a bit over
ideal DWs.
>
>Not having seen all this data before, it seems rather erratic to me. How
in the world can the BWs range from 49.0 to 60.5? And that is with a very
smooth SW. I assume this is mostly erratic leading? Leading is two in bass,
one in tenor, small one near center rail in treble, and one in rear of key
in high treble. I just played around a little with weighting key #16, and I
would have to add two big leads and one small one to get near the FW Target
or Ceiling. But perhaps that is OK - basically three big leads in the bass
keys.
>
>Recommendations?
>
>I should point out here that this piano is in a small church, and it seems
that the piano is not a high priority for spending money - so I'm probably
not going to get to do everything I might want.
>
>I could trim all hammers, but I hate to have hammers too light for tonal
reasons. Geez, I look at this mess and start to think that I simply need to
take a saw and cut off everything above the keyframe and start all over. Help!
>
>I know I can trim hammers a bit, and add lead until I get about to where I
want to go, but that seems so........ pre-cambrian. Waddaya think?
>
>I think I also need to regulate out a few notes to be sure that the
current geometry is not requiring excessive dip.
>
Roger Jolly
Balwin Yamaha Piano Centres.
Saskatoon/Regina.
Canada.