Hi All, I've just finished uploading the article, "Duo-Art Cross
Valves, Again?", by Craig Brougher. In the article, Craig provides
pictorial evidence and addresses the problems associated with the
Duo-Art cross valve plate, and he explains why rebuilders almost never
experience any problems when they simply replace the valve facings.
Also, using an easily understood example, he explains the advantages
of a circular valve plate over those of a cross valve plate. He also
relates the findings of an experiment that was conducted during an
AMICA convention which demonstrated the difference in the flow
characteristics of the two valve plates. Lastly, he explains what must
be done when circular valve plates are used to replace the troublesome
cross valve plates.
As an interesting side, he also explains why Steinway continued to use
the cross valve plate long after others had ceased using them. You will
be interested to learn that it had nothing to do with the quality of
the Steinway piano.
The article can be accessed by pointing your browser to
John A Tuttle
Brick, New Jersey, USA