Player Brake Adjustments (Roll Paper Slipping Problems)

When it comes to the brake tension on the player for the upper paper
feed area, the lighter the pressure the better.  I know that this
doesn't make sense but try it.

Note: There still has to be some pressure to help with the tracking of
the paper.

The older piano rolls are not affected by the brake tension as much,
because the paper is so rough and has lots of fibers to hold onto the
next layer of paper as it is rolled up on the bottom take up spool.
The thickness and how spongy the paper is may also contribute to it
not slipping.

It is the newer roll paper found on the large jumbo rolls that almost
always slips at the end of the roll.  The paper is extremely thin and
slick.  As the paper winds on the bottom take up spool, it wants to
slip no whether what tension it is wound at.

If there is no tension put on the top feed spool, the paper on the
bottom spool is still being wound under tension because of the vacuum
holding the paper against the tracker bar.  This is somewhat constant
depending on how much vacuum is being used to drive the player stack.
You can't control this.  It is just there.

The problem is in the roll brake that is found on the top of the spool
box.  As paper is taken off of the top feed roll, the diameter of the
paper coming from the roll gets smaller.  As it gets closer to the end
of the roll, the diameter is as small as 3/4-inch, and the tension that
the brake adds to the end of the playing roll gets extremely high.

The bottom spool has the paper wound less tight on the bottom layers
and progressively tighter paper on the top layers.  If any of the
bottom paper layers start to slip, even slightly, the diameter of the
roll at the point that the paper started to slip also gets smaller.
This leaves a gap or pressure difference between the two layers of
paper and it slips even more.  This slipping works its way up through
each later of the paper until the tension in all layers equalize.

The more pressure you put on the top brake, then the tighter the entire
roll will be wound on the bottom spool.  Your problem is still not
solved because there is still the problem of the paper being wound
looser at the beginning of the roll than at the end.  The paper still
stalls and slips.  I have seen the slipping problem get worse as you
add more brake pressure.  The other problem with this is that the tempo
also slows down excessively as you get closer to the end of the roll.

When placing a light pressure on the top spool brake, then the tension
of the paper from one layer to the other is less drastic and will not
be as likely to start slipping.  All you are doing is delaying the
point where the slipping will start to happen.  Hopefully it won't slip
until the entire roll has played.

Oiling the brake -- For some reason people want to place oil on the
brake pad, or else the oil from lubricating the transmission seems to
get onto the top brake pad.  It is very important that this pad and
brake wheel be void of all oil.  The oil causes the pad to stick to the
brake wheel and put unneeded tension on the top roll.

The pad is usually a piece of felt glued with the old fashioned hide
glue.  If you find the brake sticking too much, try replacing the felt
with clean felt or just use some solvent to clean some of the old oil
residue from the pad and brake wheel.

Pete Knobloch (Tempe AZ)

 [ If the air motor slows as the roll is playing, something is wrong!
 [ The familiar story, "the motor is _supposed_ to slow down as the
 [ roll is played", is only an excuse.  The air motor speed should
 [ remain constant if the air motor and governor have been properly
 [ rebuilt and are airtight.   -- Robbie