> In 011129 MMD, John Page wrote:
>
> > The spacing of the keys is the usual 3.5 mm (or more precisely,
> > 3.49 mm) with 10.5 mm from the leading edge to the centre of the
> > first key.  The width of the music card is 264 mm.

I think John Page is right with the spacing of the keys (3.49 mm),
but this is not specific in Carl Frei organs.  It is the normal
Gavioli/Limonaire spacing which later is used by many others, including
Belgian organ builders (Mortier, Bursens, etc.).

Rein Schenk

 [ Carl Frei, and others, adopted many aspects of Limonaire technology.
 [ Herbert Juettemann's book says that the 67- and 72-key organs by
 [ Carl Frei (based on the 56-key Limonaire scale) used 3.5 mm key
 [ spacing, while his organs of 90 keys and larger used 3.48 mm spacing.
 [ The difference is negligible.  -- Robbie