Dear All,  I have been searching for details of an air flow comparator
gauge to be used to balance air flows on primary valve bleed screws.
I have verbal information (by telephone) about how to make one.

It is no more than a small air motor with a pointer fixed to the moving
leaf, the opening of the motor is loaded with a very light spring and
a hole for air bleed-off is drilled into the motor top.

It seems that the dial is marked to the position the pointer assumes
when tried on a primary valve which appears to be operating okay.  The
other bleed screws are then adjusted in turn until they are all set to
the same mark.

Does a drawing exist of such a device?  Would there be any advantage
in using such a device to set up primary bleeds?

I have made one which appears to work okay, but would be interested to
hear of its use (if any) elsewhere.

Also I would like to thank MMD and the many contributors who have
freely given advice to help me with my build of an organ based upon the
R Norman plans.  Having first become interested last September I now
have an organ that plays well and doesn't upset the neighbours (as yet).
I still have to finalise the build of the cabinet, but having put so
much work into it I am reluctant to cover it up.  Perhaps a Plexiglas
back and front.

Arthur Nichols
Wolverhampton UK

 [ The air motor device you describe seems to be actually a suction
 [ indicator.  Wouldn't a needle valve and an ordinary suction gage
 [ or manometer serve as well for your task?
 [
 [ See also "Airflow and Leak Measurement Equipment" by Phil Dayson,
 [ indexed at http://mmd.foxtail.com/Archives/Authors/Aut783.html
 [ I believe that Phil's instrument can measure both comparative
 [ air flow and absolute air flow.  -- Robbie