[pianotech] Balance rail bushings

[Jon Page]

I've found that it's not the length of time the caul is left in but 
the right thickness cloth.

I'm installing bushings on a Bjur upright, fantastic piano.  1mm was 
too loose (.040"),
1.5 mm was too tight (.060"), 1.4 mm was just right (.055).  If cauls 
fall out by their
own weight, the cloth is too thin. A firm but not tight fit makes for 
a good gap.

Experiment with placing the cloth dry in the mortice and feel the 
play on the key pins.

Use a chisel point Exacto knife to remove any glue bead which may have formed
at the  bottom edge of the cloth.  Finish the buttons with 180 or 220 
grit sand paper
on a palm sander in groups of 8 to 10.
-- 

Regards,

Jon Page