advice on action parts

[Jon Page]

>
> At 06:29 PM 3/24/99 -0500, you wrote:
> >In measuring S&S's, I found the KR to run between .52 to .54 and with
> >some  .56 to .58.  Some were .46 to .49.   But there is no evenness to it.
>
> Wow, .46?  That's unusual.  Is the unevenness due to a crooked capstan line
> or too skewed one way or the other?


One S&S was .51 to .56, invariably a higher number in the treble.
I would hazzard a guess that the balance rail holes are uneven.
It takes about 1/16" movement of the capstan to affect .01 KR.

Generally the sharps will have a lower ratio than the naturals
ie: .54 / .52.   Only 1 Kawai and 1 Baldwin SD10 had dead even KR 
and then the sharps were lower. S&S looks more like a player roll
when plotted on a graph.

>
> >I have not needed to move the capstan often to the alter the KR.
> >I don't arbitrarily pick a KR, and then_make_it  work. I chose a KR to make
> >the action regulate 'properly' (tounge in cheek) with the appropriate
> knuckle and
> >adjust weight from there.   
>
> When you do decide to move the capstans, how do you determine where to move
> them?
> Trial and error, to see how the action regulates for one key?  IOW, how do
> you decide when
> to use a slightly less than 2:1 ratio (say a .54)?  So you use shanks other
> than 17mm?  When?


I consider moving the capstan if the jack either does not clear the knuckle or
is buried into the stop felt when other parameters are within tolerances.
Moving the jack affects the regulation too much to use it to reduce DW.
I would consider it for that regard if the regulation would accomodate the
change.

Jon Page