Hi all...

Does anyone have a view on the relative amounts of dish given to
pouches that operate in a horizontal fashion,  as opposed to
vertically? I have read and re-read Art Reblitz's chapters on pouches
and cannot find any suggestion as to differential treatment.

I ask because I am just restoring a very straightforward Autopiano.
The valves have the usual fiber disks screwed on to metal stems,
seating to nickel plated metal seats inside, and wood outside. Felt
covered wooden buttons and fiber bushed guides complete the valve
assembly.

The pouches are of a fairly standard size, with cardboard lifter disks.
The well is about 3/16" deep, and the use of a pouch setter resulted
in quite a noticeable dish. When tested, in vertical fashion, the
pouch inflated,  but did not return as easily as it would if gravity
were assisting it as in horizontal mode. As the original pouches had
very little dish, I then tried the following:

Install a pouch with no dish, i.e. flat over the well top. Place the
lifter disk on top with just a small blob of glue underneath its
center. With a fingertip, stroke the disk in a circular manner,
easing down gently (but firmly) so as to create enough dish such that
the top surface of the disk came level with the surface of the pouch
perimeter. This kept much of the tension in the leather pouch so that
upon testing, it returned of its own accord, but still gave lift of
0.150".

My question, therefore, is this:

    Should the orientation of the valve and pouch assembly have a
    bearing on the dish size?

Roger Waring

Solihull England