Hello, I am a new member and have read only two of your lists of
articles -- very interesting.  I have noticed several discussions on
Tracker Bars.

I made a tracker bar out of 1-1/2-inch diameter, 3/16-inch-wall
aluminum tubing, and cut it in half lengthwise and drilled holes as
needed.  This one is used on 65-note type "A" Nickelodeon rolls and is
electronic, using infra-red sensitive photo cells instead of a pneumatic
system.

There is no reason brass tubing cannot be pressed or epoxied in the
rear of the holes for a standard vacuum operated instrument.

This one has been in use for over 10 years and, other than additional
polishing, is showing no signs of wear.

Will be glad to share details if helpful to anyone.  I took some
photos, not scanned yet.  Located in So. California

Jody, thanks for all

Lee Roan
LROAN2@aol.com

 [ Welcome to MMD, Lee.  We've heard rumors about your optical roll
 [ reader, and I hope you'll tell us more about it soon!  -- Robbie