Finding good felt, like the original used for backing valves in players
has been a problem.  Most felt bought on the market today is largely
synthetic; coarse, lacking in density, and not of uniform thickness.
The only source of true, dense red wool felt that I have found is
'Organ Supply Industries' product number 61201.01, but it is 1/16 in.
(.0625) thick.

  Organ Supply Industries, P. O. Box 8325, Erie Pa. 16505-0325
  tel: 835-814-2244

Center rail punchings are made of 'cloth', a 'fulled' fabric, that is,
coarsely woven cloth treated on the surface to bring out the fibers,
so it looks like felt.  All piano supply houses sell a variety of
thicknesses of 'cloth' in wide strips suitable for your purpose.  I am
not sure such cloth would be correct for valve backing, however.  It is
made deliberately firm and unyielding, and is somewhat lumpy on a very
small scale.

I wish an MMDer would come up with a source of good wool felt, cut 1/23
or 3/64 in. thick.  Has anyone tried using 'thin bushing cloth' in
place of felt in valves, and can report on the experience?

Richard Vance