It does not really matter how many numbers you can read on the tension
of friction brakes. What the factory did does not matter, either.
It is not the same today after 80 years of playing, or even 80 years
of sitting there not being played. Also, you certainly do not want the
factory's tension on the paper of an 80-year-old roll. I can tell you
what I have done with every player I work on and/or rebuild, though.
The felt on the brake should be saturated with oil or grease or you
will have trouble with the brake. I know, you just pulled off that old
oily felt (or leather), but the new pad must also be greased up or
oiled as well.
The take-up spool test for the correct tension is this: Set the gears
to reroll and put your hand on the take-up spool and spin it.
Approximate the speed of the rewinding roll. It is set correctly if
the take-up spool spins about one turn and stops.
To test the lubrication and the correct free working of it, pull the
brake away from the disk and spin it. This time it will spin several
times, or many times if everything is freed up and working well. Set
the brake so that it only spins the one time and you will not damage
those old fragile rolls. Many folks remove this brake completely, and
you can do that, but that can allow the rewind to have trouble if there
is no tension in the brake at all.
The Play brake on the top [supply] spool should also be only tight
enough to keep the paper from chattering as it unrolls. If you take
the brake off completely, the roll will not be tight against the
tracker bar in many cases and you often can watch it jiggle as it
moves. Just enough tension to stop this is the correct amount. Too
tight here can also damage old fragile rolls.
That is my technique.
D.L. Bullock St. Louis