S & S 'A' parts, geometry -- shanks and flanges

[A440A@AOL.COM]

John asks:
>not tested larger knuckles to see their effect.
>
>Does anyone have results from such an exchange?

Greetings, 
   One of the first effects, on Steinways, is that there is less room for the
jack after escapement.
   Also, all other things being equal, the larger knuckle will start the
whippen at a lower position relative to the  shank, thus altering the
coincident range of the arcs formed by these two radii. 
Regards, 
Ed Foote