Hi MMD, I have found the comments on old rolls tearing up on rewind to
be interesting.  There have been many suggestions as to the cause and
the cure.  However in my opinion every writer missed the most important
cause.

A little background.  I'm 79 and have been repairing rolls for around
35 years.  For approximately 10 of those years I bought mega thousands
of junk rolls on eBay and from private collections.  I found that
I could not pay more than $.25 to $.50 for a roll and hope to make any
money when the repaired roll was resold on eBay.

Now the main reason old rolls tear up on rewind is very simple: the
core tube is too short!  Listen carefully to the reason.

Old paper on old rolls lacks rigidity.  When the roll is put in the
spool box, the left flange (the idler flange) is under constant
pressure.  If the left flange is slightly loose as the roll size
decreases as the roll plays, there is less and less paper to hold
the flange from being pushed in.

The only thing that stops the idler flange from being pushed in is
the tube.  If the tube is too short, i.e., less than 11.25 inches,
the distance between the two flanges becomes insufficient to allow the
paper to fit between the flanges.  In this situation the paper during
rewind is pushed over to the right side and tears up during rewind.

There a couple simple solutions to this problem.  The idler flange
must be kept from being pushed in during play.  First put a couple
laps of Scotch tape around the flange shank to tighten it in the tube.
Secondly put a couple twists of a rubber band on the flange shank
close to the hub.  What you are doing here is to keep the flange from
being shoved too close to the short tube.  Hope this helps.

Now if any one is interested in another diatribe I'll outline how to
repair a roll where the paper wanders from side as it plays.

Best regards,
Tom Hutchinson