Thanks to Spencer Chase for the link to the post on the 1911 music roll
standards.  It did answer all but one of my questions on spool ends.
Obviously all spool ends by all manufacturers were to adhere to these
standards.

My last question, which remains unanswered, concerns the slip fit of
the left spool end on the cardboard core.  But I suspect that the
requirement was that the left end should move freely on the core to
allow for expansion and contraction of the paper due to humidity and to
ensure that the left spool end is in contact with the paper when the
roll is inserted in the chucks.

I should explain my reasons for this inquiry and it concerns a tracking
device invented by Frank White of Wilcox & White.  It is a tracking
system that does not rely on either edge holes in the tracker bar or
tracking fingers.  It makes use of only one pneumatic to move the roll.

After studying the patent and some adjustment instructions I found
in an early Angelus booklet it was obvious that the purpose of this
tracker is to keep the overall roll (rather than just the paper)
centered over the tracker bar.  So this system would be dependent
upon the paper meeting the flanges on both ends during use (and so both
spool ends to be dimensionally the same) and, therefore, the left spool
end must float freely on the cardboard core.

Even allowing for expansion and contraction of the diameter of the
cardboard core, this system would work well on new rolls and with
rolls whose flanges are made from plastic or Bakelite (like Ampico) as
long as the left flange is free to move.  But I have observed that the
left side Aeolian flanges (Aeolian cut the rolls for Wilcox & White)
which are of stamped and formed metal are, for the most part, too tight
on the cardboard care to move, often even with great effort to manually
pull them out.

I suspect this is due to the tendency of the formed and pressed metal
wanting to "unform" slightly over time due to the stresses imparted to
the metal due to the forming process.  And also sometimes from rusting
of the metal just from ordinary humidity.

This particular tracker system was an improvement over their older
system that used a single tracker hole on the right side of the bar
which also worked well if the above parameters were met, but if there
was any damage to the right edge of the paper the tracker would over
react and damage the roll further.  The later "White Tracker" would
work effectively even on damaged rolls,  but its weakness seems to be
its dependence on spool ends meeting the original standards.

Dave Krall