"A Brass Band In A Piano?  Give Me A Brake!"

Pete Knobloch gave a very good analysis of the play-brake problems
encountered on player pianos in 001023 MMD.  The reason I say that
is because he came to the same conclusions I did when I analyzed the
problem a few years back!

While I doubt that there are many who will go to the lengths I did
to solve the problem, some might be interested in reading about it.

I realized the problem of the shrinking roll diameter was at the base
of all the problems.  Basing my design on the Model B Ampico roll
brake, I had a machinist make up several parts.  I removed the friction
wheel and substituted a solid cylinder of steel about the same diameter
but perhaps 1-1/2" wide.

Instead of a "shoe" adding friction, I made a band cut from thin brass
stock and then attached bushing cloth with contact cement.  This band
was 3/8" wide and a few inches long.  The intent was to make a
"loop-the-loop" around the cylinder.  I am sure you can see how
friction can be varied around the cylinder by changing the tension of
the band.

I installed a thin rod in the spool box that went from left to right.
On this rod, I attached a brass tongue that touches the back of the
music roll.  The fatter the roll, the further back the brass tongue
swings -- and the harder it pulls one end of the "brass band" (no pun
intended).  The other end of the band is attached to a small pneumatic
that collapses during play mode.

Basically, when a large roll is put in the spool box, the brass tongue
and the little pneumatic are opposing each other at the highest
tension.  The band is tight around the cylinder and so there is a lot
of friction holding back the paper.  As the roll plays down and gets
closer to the cardboard core, the brass tongue is swinging in and
relaxing its pull on the brass band, so the playout tension relaxes.

Finally, when the piano is in reroll, the little pneumatic opens up
and relaxes the brass band so much that the mechanism might as well
not be there.

As if this wasn't bad enough, the piano I did this in is my 1913
Steinway pumper grand piano.  I refuse to mutilate this piano in
any way, and the entire mechanism had to be designed so that it could
be installed without any form of drilling or sawing; in other words,
if the gizmo were removed, there would be no evidence that it was
ever there.

The results were worth it, though: it's the best playout brake
I ever worked with.  Once I had it adjusted, I could play a large
modern medley recut on slick paper with no slipping -- and the wind
motor was not straining either.  When I grabbed the right flange of
the roll, there would be no slippage and the wind motor would just
stop.  I don't see how you can get better results than that.

Randolph Herr