Regarding Mr. Goodman's questions about single-finger tracking.  It's
been my observation that a single finger tracker that is in operation
during rewind doesn't work very well, because, as you said Steve, the
feed spool will plough into the roll the wrong way as it attempts to
compensate for paper shift.  I can't imagine how such a thing ever
worked originally.

Further, if you kill vacuum to the system during rewind then it will
fall over to one side as the tracker pneumatic opens.  The only way I
have been able to get these things to work is to rig a pneumatic lock
on the shifter that pushes it to mid-point and holds it there during
rewind.  The mechanical "fish-pole" trackers did this by simply locking
the mechanism where it was when the shift to rewind was made.

I guess the single-finger tracker would work okay if the roll were
perfect and it wound up absolutely true on the take-up spool, but God
help you if it didn't!

Mike Kitner