Correct strike point

[AAAPianoServic@AOL.COM]

I understand there is a mathematical formula to figure the correct strike 
point on a string.  Can someone please let me know what it is?

I am attempting to correct a very bad hammer replacement job on the top 1/3 
of a Baldwin Hamilton console action.  I am working under the assumption that 
the strike line should be straight and the hammer angle on the shank should 
be the same.  I don't want to duplicate the last horrid job so I need to 
start from scratch.

I am replacing the shanks because the height was uneven and I had to redrill 
the hammers because the angles were way out of proportion.

Thanks in advance, 

Dave Streit
Associate