Pat DeWitt posted a question in the 101012 MMD about shifting-tracker-
bar type roll tracking.  I have a 1928 Weber Duo-Art grand with such
tracking and found that, after I disabled the reroll brake, it doesn't
shred old rolls, big or small, on reroll at all.  It rerolls fast, and
the paper seems to ride above the roll core for a little bit while the
air escapes between the paper and the roll core, allowing the paper to
be very gently guided by the roll flanges to settle perfectly in the
middle, with no damage.  It did shred a roll's edge from time to time,
before I disabled the reroll brake.

The one thing that I see as an advantage of tracker bar shifting is
that the roll and the takeup spool remain in perfect alignment with
each other at all times.  What is critical is that this alignment must
be set right.  It depends on the left flange of the takeup spool being
directly below the edge of the left flange of the roll, so it keeps the
paper from drifting to the left on the takeup spool as it plays.  This
keeps the paper from tearing itself up on the left roll flange when it
rerolls.

The one disadvantage of tracker bar shifting seems to be that there are
a very, very few rolls apparently having out-of-spec right flanges that
force the roll alignment a little too far to the left, causing the roll
to shred on the left as it winds onto the takeup spool.  These I don't
play.  If there were more than two or three rolls out of my whole
collection that do this, it might be worth rigging up an adjustment for
these rolls; but I don't think it's worth the trouble for now.

Since the tracker-bar shifting system seems to preserve rolls better
that any roll-shifting tracking systems I have experience with, I would
recommend against converting the tracking system to roll-shifting.  It
just may be that the tracker-bar shifting is actually an improvement,
when all is said and done.

I believe that it had been stated somewhere that Aeolian was unable to
get satisfactory tracking for their Duo-Art pipe organ rolls with roll-
shifting tracking and went to tracker-bar shifting for them.  The pipe
organ rolls were much wider and the note spacing was 12-to-the-inch
instead of 9-to-the-inch.  This also required that the tracker bar
would expand and contract its width to compensate for paper expansion
and contraction, due to changing moisture levels in the air, which did
add a lot of complications to roll-shifting tracking.  Aeolian's
success with tracker-bar-shifting tracking for their pipe organ rolls
may have led them to go with it with on their later player pianos.

Dick Merchant
Carlsbad, NM