RE: Steve Greatrex's Post

Steve,

First of all replacing the cross valves with round ones will not work
unless you are prepared to add a set of primaries.   Aeolean wanted to
save the expense of adding primaries.  The cross valve design creates
an aerodynamic action that  enables a smaller pouch to power a larger
valve, thus eliminating the need for a primary stack.  If you replace
these with round ones you will have poor repetition and failing notes
at the soft levels

The problem with the cross valves is mainly the fact that these were
installed right out of the punchpress without any finishing  and in
most cases the surfaces are highly irregular.  All cross valves that
I have seen in stacks have been nickel plated brass and they do
not bend that easily.  However I have come across some in expression
boxes that are aluminum and bend by just looking at them.    I
devised a machine using a fine grinding wheel and kind if a *tone arm*
device for milling a true flat surface on the plates.   After they are
installed,   I carefully test and regulate valve travel on each note.

I have done 7 stacks this way so far and have no problems or complaints,
The only troubles I have encountered otherwise are:

   (A) The wooden valve might be warped on the stem.  These can be put
       on a lathe and trued up.

   (B) Some nut before you reamed out the fiber valve stem guide washers,
       or the top and the bottoms got mixed up ( they are different)

Brian Thornton

Short Mountain Music Works
109 North Cannon Street
Woodbury, TN 37190
Ph: (615) 563-5814
smmw@mindspring.com.geentroep [ drop .geentroep to reply ]
http://www.mindspring.com/~goatboy/smmw.htm