Hi,  I am just rebuilding a Welte Licensee rotary box pump; the piano
is dated from around 1926.  The pump had been restored previously and
I am a little suspicious of the width of the cloth that the bellows
have been covered with, i.e., the full open measurement of these
bellows before being mounted or connected to the crankshaft.

I feel that the bellows, because of too much cloth, are not opening
fully or properly and so when opened and closed via the crankshaft only
a percentage of the suction total volume is being made.  Obviously,
if they open completely the bellows cloth would billow out and not fold
in as they should do.  I do hope this is not too rambling.

If anyone can help on what the maximum opening width actually is --
with the size taken from an actual original pump or rebuilt pump --
I would be most grateful.

Jonathan Holmes.
Penzance, UK
talveneth@aol.com.geentroep [delete ".geentroep" to reply]