grand hammer spacing/traveling

[Allen Wright]

I've always traveled grand hammers so that they move straight up and  
down, not drifting one way or the other, and then spaced them to the  
strings. I've heard that there is another method - perhaps it's a  
factory approach - of spacing the hammers more cosmetically (evenly  
spaced), and then if necessary traveling the hammers to compensate  
for the fact of uneven string spacing due to agraffe placement, so  
that the hammers end up being "spaced" to the strings due to their  
slight off-90 degree travel up to them.

I can understand the cosmetics argument from a manufacturing and  
sales point of view (although I have to wonder how many pianists  
would notice or be bothered by wonky hammer spacing necessitated by  
uneven agraffe placement). What I'm uncertain about is whether or not  
(and at what point) compromising hammer travel like this has an  
impact in terms of uneven forces on the flange, possible voicing  
issues, and other factors I may not be aware of.

Would it have to be fairly exaggerated for there to be consequences,  
or might the slightest discrepancies have an effect? Is this a mostly  
theoretical issue, or a practical one? I wonder if it's the kind of  
thing that Stephen Birkett's photography explorations might somehow  
shed light on.

I read some interesting list archives on spacing/traveling issues,  
but didn't quite find what I was looking for. Any opinions on this  
will be appreciated.

Sincerely,

Allen Wright, RPT