I asked the same question on MMD several years ago as Dave Krall did in
the 06.10.03 MMD.  Apparently, the problem with today’s (and 1970’s
too) leather nuts is corrosive residues which remain from current
tanning processes.  I had rebuilt a Welte drawer in the late 1970’s.
When I got ready to install it, some (ahem) 20 years later, I observed
the same problem, only worse; some of the rods were almost corroded
through!

A very knowledgeable friend introduced me to nylon nuts, which are used
in the organ trade for these kinds of applications.  While I am a
believer in using original materials, it stops when "original"
materials are not original with respect to the way they are made.  In
disgust, I installed the drawer anyway.  I should have taken it all
apart again and tried the nylon nuts.  After all, since we are only
custodians of these instruments, "First, do no harm."

At the time I posted, nobody had much to say about this problem, and no
one responded with personal experience in using the nylon nuts in place
of leather.  Maybe someone will respond this time.  This problem has
got to affect almost everyone who has rebuilt a player action.

Bruce Duncan,
Rockville, Md.