YC Strike Weights etc

[David Love]

Why would you move the capstans?  What are the BW's on these samples.  Is
the convergence line for the naturals where you want it?  If the balance
weights are generally where you want them then the FW's are in the ballpark.
You won't be able to get an even key ratio and maintain a straight capstan
line.  Somebody screwed up at the balance rail and keys positioning the
balance rail pins.  You will have a bumpy graph on the FW's because of the
KR differences between the naturals and sharps.  No avoiding that.  A
staggered capstan line will create other problems.  Unless you are willing
to remake the keys, I would just live with it, make sure your SW's conform
to your desired BW/FW.

David Love

----- Original Message -----
From: "Richard Brekne" <Richard.Brekne@grieg.uib.no>
To: "PTG" <pianotech@ptg.org>
Sent: November 01, 2001 2:26 PM
Subject: YC Strike Weights etc


> Hi folks..
>
> for those of you who are interested in such... I am starting off on
> another evening out of SW's and the rest ala Stanwood (as described in
> his Touchweight design kit sold by Protek) This job is pretty odd as
> evident by the key ratios you see below. The white keys all weighed in
> at 5.5 and the blacks at 5.2 (or pehaps actually 5.1).
>
> I am not entirely sure how to handle this one... my instincts tell me to
> move the caps so that a uniform KR is achieved...but I am not getting
> payed enough on this job to justify that.... but the thought of a
> staggered set of capstans is interesting enough.
>
> Anyways... here are the basic numbers
>
> #     FW     SW     KR     WRW
> 1      28.9    12.6    5.5     18.7
> 10    31.5     12.2   5.2     18.4
> 11    33.3     12.1    5.5     19.0
> 20   26.1     11.7    5.5     18.6
> 21    24.6    11.6    5.5     18.5
> 36   27.1     10.6    5.2     18.5
> 37   25.2     10.8    5.5    18.4
> 51    14.8     9.8     5.5     17.9
> 52   15.5      9.5     5.5     18.6
> 60   15.8      9.4     5.2     18.1
> 61    15.6      9.5    5.5      18.2
> 68   16.0      9.4    5.5      18.9
> 69   13.8      8.7    5.5      18.0
> 77   21.4      8.2    5.2      17.4
> 78   17.9      8.3    5.5      17.9
> 88   11.5       7.0    5.5      17.8
>
>
> Again I see some odd ball FW's... tho not as bad as that Seiler I just
> did. Here tho are some pretty large differences between Whippen Radius
> Weights... over 1.5 grams from the lightest to the heaviest.  SW's seem
> pretty evenly curved tho... and I think I am beginning to see a tendency
> by manufacturers to have treble hammers a bit heavier relative to the
> rest of the piano then Davids published curves show.
>
> I suppose as time goes by and I gain more experience with all this I
> will understand more about why that is so (if it is.)
>
> Anyways... new hammers are now installed and I will be weighting them to
> follow a SW curve from Davids SmartChart that starts at 12.6 grams. I do
> that tommorrow and start the rest including regulation and voicing
> tommorrow. I still have the chance to make a few decisions so if any of
> you have some words of wisdom for me... well by all means !! :)
>
> RicB
> --
> Richard Brekne
> RPT, N.P.T.F.
> Bergen, Norway
> mailto:rbrekne@broadpark.no
>
>