On treadled players, the reroll brake serves a very important function
in most brands of players (not all). On reroll, if the roll was
tracking poorly and required a lot of correction to play it, then on
reroll when the tracker mechanism is turned off, that roll will tend
to tear as it winds hard against the roll's own flanges. So many
rebuilders completely remove the reroll brake. That is understandable,
and it works-- as long as it happens to be an adult doing the pedaling,
who knows that you don't stop pedaling until the roll is safely rewound.

With kids, it's a different story. If they get the roll going back
fast and then stop pedaling, they c an have twice the fun, as the paper
stops taking up on the roll instantly and the take up spool is still
going at top speed!  Whee! It flies out of the spoolbox and sometimes
hits them in the face!  That's fun! But death to your rolls. If you
wish, you are welcome to set up your spoolbox that way, but I have a
much better suggestion:

Stop thinking about your rewind brake as a "roll tightening device."
It isn't. It is there for one reason-- to prevent uncontrolled paper.
That means, you don't adjust it so that even the large rolls are
squeaky tight, but use it to prevent freewheeling takeup spools. That's
all it does. It keeps the paper in the spoolbox on a fast rewind.

Now granted, some techs I have seen obviously didn't understand the
purpose and didn't know how to set it. Sometimes, the felt or leather
button thy used was allowed to cock slightly on the bull gear or brake
disk, causing too much tension, and they didn't replace it, or they
oiled it, thinking that this would fix it. "If a little oil is good, a
lot of oil is better, and a grease gun is just fantastic!" But don't
do it that way, and don't expect to have a proper reroll brake if you
have oiled the bull gear.

Craig Brougher