Darrell Clarke said a friend of his had a problem with a Standard action
tracking system which seemed to tear rolls on rewind. While there could
be a dozen reasons for this, I will assume that it is retubed correctly,
the screens are clean, that the outside hole pair automatically cut out
when the inside hole pair is tracking, that there are no leaks in the
system or the differential tracking pneumatic, and that everything is
mechanically secure and solid, without lost motion.
Having assumed a lot, I will suggest that he may have a reroll problem
for two reasons. 1) He has not adjusted the tracking cam to be in the
center of its travel on the roll chuck when the differential pneumatic
is in the center of its travel, or 2) he has not set up the adjustments
for a number of rolls, rather than just one or two rolls.
When playing, a misadjusted tracker can still be moved over enough to
track most rolls just fine, anyway. Especially new ones. It's always
on reroll that you realize that the tracker isn't properly adjusted.
The spring under the tracker pneumatic is supposed to very slowly
raise it to take the pressure off the roll chuck (if I'm remembering
correctly). That allows the roll to sidle left against its loose flange.
However, if it's tearing on its left flange, the problem could be that
the roll tracker had to track too far toward the right direction in order
to keep the roll centered as it was.
The principle of a tracker that is not vacuum-clamped to the center
during reroll is that it was designed to just move gently across the
center balance position occasionally during play, rather than requiring
full extremes constantly to keep a roll in line. The spring is adjusted
such that it is supposedly able to center the pneumatic and no more, but
I have not found it to be as effective as the vacuum-centering cut-out
device used by Aeolian.
When initially setting up a standard tracker, take a couple of 1/2-inch
leather nuts and jam them into the 2 sections between leaves of the
bellows such that you center the device perfectly and do not permit it
to even budge!
The next thing you do is to disconnect the vacuum to it, put on a roll
that you know is a good tracking roll, and align that roll's note holes
which are furthest to the bass side with the note holes in the bar. You
do this by marking the exact enter of the roll chuck cam and then
loosening it up on its rod and sliding it in or out until the roll
is centered in the bass (only). Don't center a roll from the center
holes!!! As you play this roll without a tracker action, you will see
which way it drifts, if at all. keep making adjustments as needed, but
don't jump to conclusions the first time you see it drift.
Tighten up the cam, remove the nuts and give the roll a try. As you play
rolls, you will have to make adjustments on you initial adjustment. You
will notice the machine favoring one side consistently more than the
other. Play about 20 rolls, good, bad, new, old, everything.
The Standard roll tracker's weak link are those wooden bushings that
carry the crank rod the cam is clamped to. The glue joints like to pop
in those things and it gives your tracker too much lost motion. And any
other links, even the wire link to the rod has to be free but snug
without lost motion. Naturally, the mounting screws to the tracking
device must also be good and tight.
Finally, there were two kinds of tracking cams. One was stamped metal,
and the earlier one was cast. It doesn't hurt to give the stamped cam a
little more twist -- but very little. We're not talking 6 degrees, here!
But as the years went by, the stamped metal cams were bent back by many
pumpers who pushed the roll drive clutch hard as they inserted and removed
rolls, springing the cam, and also breaking the glue joints of the wooden