Friction/StrikeRatio

[stanwood]

I've been thinking about the recent discussion on reducing friction with
small knuckles.  I've noticed that changing the ratio by moving the
capstan-heel position also changes friction.

The data below shows FrictionWt as (DownWt-UpWt)/2
Before and after moving the capstans and heels
approximately .375" to change strike ratio from an average
level of 7.5 to 5.5

The data is from a model D #51428 at Harvard University


Note     7.5      5.5        Friction difference

  1     18.5     11.5            7.0
  2     23.5     16.0            7.5

 16     26.0     12.0           14.0
 17     21.0     11.5            9.5

 28     18.5     10.5            8.0
 29     14.5      9.0            5.5

 40     18.5     10.0            8.5
 41     15.5     10.0            5.5

 52     13.0      8.5            4.5
 53     18.5     12.0            6.5

 64     18.5     12.5            6.0
 65     16.5     11.5            5.0

 76     13.5      9.5            4.0
 77     14.5     10.5            4.0

 85     13.0      7.0            6.0
 86     14.0     11.0            3.0

In the above example, nothing was done other that moving the capstan line.
NO other friction work was done.  Moving the capstans killed two birds.
The friction and the ratio both were corrected.

The piano played liked a nightmare, now it plays like a dream.

Small knuckles would not have solved this problem.

David C. Stanwood