Graphite on knuckles

[Kenneth Sloane]

                      Subject:                              Time:  9:50 AM
  OFFICE MEMO         Graphite on knuckles                  Date:  4/26/96

At Oberlin, we have summer cleaning crews that wash keys, scrub down cases,
remove actions to clean and lubricate keybeds and keyframes,  etc. While the
action is out of the piano, student cleaners lightly press on hammers as they
play keys through the let off point and feel and listen for evidence of
friction. If friction is there, we clean and lubricate the knuckle area.
Before I describe the procedure we use, I should mention that most friction
problems in the knuckle area occur when we work with pianos having replacement
shanks that used a buckskin of inferior quality to cover the knuckle. For a
period of time several years ago, the piano industry could not secure a
sufficient supply of good  quality buckskin. Thank goodness that supply
problem has been solved.

Our procedure -- Even though the rep lever surface, jack top, and knuckle look
clean and "polished" in virtually all our pianos (we use no "gooey" lubricants
in this area), we first clean and buff all bearing sufaces with a soft, cotton
cloth. That will invariably alleviate if not eliminate the symptoms of
friction, but experience has taught us the "cure" is short term. To make
"cure'" one of longer term, we have applied the following lubricants with the
following results:

Pure Talc (no perfumes, etc. added) -- Least desirable. Did not lubricate very
well and did not last long.

Teflon  powder --  Lubricated well but did not last long.

McLube -- when sprayed on, lubricated well but made the knuckle hard. I
suspect  that spraying some onto a cloth and then rubbing sprayed surface of
cloth across the knuckle might help. As I recall, spraying just the rep lever
and jack top was not enought to eliminate friction.

Powdered Graphite -- When small amounts were rubbed into the knuckle, friction
was eliminated and it lasted the longest. Repeated applications does not
create problems. We also rub the powdered graphite on the jack top and rep
lever.

I feel pretty confident about these results because we check on these pianos
all the time and get a chance to evaluate our procedures.

Ken Sloane, Oberlin Conservatory.