Hi group,  It is not detectable by normal operation or test roll that
the split is at 40/40 or 39/40.  It is perhaps a little extravagant
to state that the piano doesn't work if the split is wrong by one note.
I could think of worse problems that make a piano not work properly.

Julian makes a statement that Aeolian changed the split from 40/40 to
39/40 at some stage.  This would indicate different roll arrangements
as well then?  I would like to see this substantiated with some
documentation or research if possible.

The 'correction' made by myself was made with the knowledge known at
that time and is 100% correct as the bleed corresponds to the correct
side of the stack where the valve is situated.  The split is at 40/40.
It was at 39/40 before.

The stack dividers on the pianos I have worked have a bend for one
valve to be on the other side.  This is not installed in a different
direction but turned upside down to allow that valve to be on the
opposite side.

It has nothing to do with 'modern rebuilders' not understanding the
instruments, try me.  Other errors exist in these pianos and it was
a natural assumption that if a stack that is a high precision item
has a crude channel carved into it with a pocket knife, then this is
an error.  If this was indeed a factory modification, then they should
have routed that channel neatly.  In fact, I have never seen such a
shoddy modification on any American or German piano.

Has anyone else 'measured' where the split point in their piano is?
I would like to hear from some American Weber or Steck owners.  What
does Douglas Henderson say?

Kind regards,

Bernt Damm
Cape Town