Bob Stewart's question about his Wurlitzer tracker bar got me to
thinking about how Wurlitzer made them.

I have never taken one apart, but they look like they are not (as they
do appear to be at first) a solid piece of brass.  They appear to be
a hollow box-like piece of metal about 1"x1"x 7" (or 10" for the 165
roll), with a thinner brass face, fitting in a shallow U-shape over its
front.  The hollow insides seems to contain brass tubes connecting the
1/16"-inch square holes in the face of the bar with the round 3/16" or
1/4" holes in the back of the bar that are offset into three horizontal
rows: holes 1, 4, 7, 10, etc., being in the top row, holes 2, 5, 8, 11,
etc., being in the middle row, and holes 3, 6, 9, 12, etc., being in
the bottom row.

How on earth did anyone solder or fasten all those tubes in their
proper places and get an airtight seal on the whole thing, when it is
put together as a completely closed box unit?  Or am I mistaken about
the tracker bar's construction?  As Bob asked, Who has seen one
disassembled?

I have seen on Art Curtze's DeKleist organ a homemade tracker bar made
out of a solid piece of Lucite (Plexiglas), into which the necessary
holes were bored in offset directions.  The advantage of the transparent
plastic was that it was easy to drill and you could see where your 1/16"
drill was going from the from the front side and your 1/4" drill was
going from the back to meet up with its corresponding front-side hole.

Matthew Caulfield (Irondequoit, N.Y.)