I'm a firm believer in Elmer's Slide-All Dry Spray Lubricant for
everything possible, rolls, boxes, all action parts, any sliding valves
(of course, when they are all apart and masked).  Wind motor surfaces
and the like should be medium-sanded, then fine-sanded, using 200, 300,
400 grades of sandpaper that are lightly sprayed on the back with 3M
contact glue and mounted on plate glass.

When sanded smooth, build a film of three coats of Slide-All spray,
letting dry between coats.  When dry, work the mating surfaces
together.  I did this over forty years ago on my Lexington Ampico and
haven't touched the piano since, except to recover it last year.

John Taber
East Hartford, CT