There has been talk lately of a possible need to enlarge player
bleeds to compensate for increasing the airtightness of pouch leather.
I would be extremely reluctant to do this.

In addition to pouch porosity, or lack thereof, consideration of the
following interrelated factors is essential in determining optimum
bleed size:

  Valve travel
  Single or double valve action
  Efficiency of valve design
  Type of valve used and diameter(s) of facings
  Pouch diameter
  Average size of roll perforations
  Stiffness of pouch
  Longevity of leather treatment
  Effect of tracker bar pump on untreated pouches

Each of the above factors alone can be a topic for discussion.

Original player actions contain a wide variety of bleed sizes.  For
9-to-the-inch tracker bar hole spacing, #65 drill size is the largest
I have seen to date.  Checking old Player Piano Company catalogs,
I find the 1978-'81 issue has the widest selection of brass bleed cups
listed: #71, #70, #68 and #64.  Durrell recommended #71 or #70 for
presumably untreated leather pouches.  I have seen sizes larger than
these used in conjunction with older and less porous leather.

Can anyone supply the sizes of unaltered bleeds for various examples
of player actions that originally used rubberized cloth pouches?

Jeffrey R. Wood