Spencer Chase mentions gasketing and screwing together his Duo-Art
expression box.  This was always the practice of Aeolian in the UK,
anyway, so it's authentic to some degree!

Expression boxes in UK pedal-electric grands normally have round-top
screws on top of the expression box outside the seal cloth, with
springs and washers to keep the joint tight as the wood moves.  Upright
boxes, otherwise identical, seem to have countersunk wood screws
underneath the top seal cloth, presumably because of the limited top
clearance in an upright piano installation.

I rebushed all the bearings in my instrument last year, and sanded
the knife valve with the finest paper on a piece of sheet glass.
I can confirm that it really makes a difference to the quiet playing.
I wonder how much the use of modern materials and bearings adds over
traditional techniques?  Although many 'improvements' are disasters,
some must be good and it would be nice to know which!

Julian Dyer