The "problem" described by Stephen Small may actually be normal --
provided the motor does not stall when the take-up spool stops.  This
intentional periodic tightening of the roll during rewind is thoroughly
discussed in the 1929 Ampico Service Manual (reprints available) under
the heading, "The Reroll Brake".  Careful adjustment of same is
critically important.

Many rebuilders disable this feature, feeling that it can damage rolls,
most notably, old ones with brittle paper.  As an alternative, rubber
"O" rings or paper washers are used on the left flange to bring it away
from the cardboard core, allowing the paper to freely wander back and
forth during rewind.  An unevenly wound roll must _never_ be tightened,
however, as this can easily train the paper to wander even more.

The proper way to handle an unevenly wound roll is to hold the roll at
its center, with its right, or slotted, flange down and supported with
the other hand while turning it back and forth, never tightening the
roll at all until gravity has brought all the paper snug against the
flange.  Some gentle assistance by tapping may be necessary if the
paper has had any tendency to pucker during the perforating process.

Jeffrey R. Wood

 [ The Ampico B Rewind and Repeat System text is reproduced
 [ at http://mmd.foxtail.com/Gallery/Tech/Ampico/amp52.htm
 [ A modification for improved shut-off reliability is described
 [ at http://mmd.foxtail.com/Gallery/Tech/Ampico/amp52m.htm
 [ -- Robbie