I've been away for a few weeks and just read Matthew Caulfield's
argument that no lubrication is required for wood on metal friction
surfaces and also Mike Kitner's recommendation for tallow imbedded with
graphite.

In 1953 I presented this question to a club of retired German
machinists. They all began their careers in shops that used steam
powered rotating metals shafts supported by wood bearings to supply
power to their machine tools using cloth belts and drive wheels. Most
of them believed that no lubrication was required for metal on wood.
They had tried many lubricants with little difference in the life of
the bearing surface. One voice of minor dissent suggested that tallow
or rendered lamb fat was useful to minimize wood swelling in shops
having considerable variation in humidity.

I've personally tried many lubricants and currently use a mixture of
cork grease (boiled lanolin) and molybdenum disulfide. I suspect that
it makes little difference but I feel better about it.

I did go through a period where I made the pump sticks out of teak and
used no lubrication. I never saw any crank or stick wear with this
combination.

Whatever one does, I believe that Matthew's argument about grit being
attracted to "wet" surfaces is correct. A "dry" lubricant or no
lubricant would seem preferable to anything that might attract grit.

Also, whatever you use, be sure that it doesn't drip on the bellows
leather.

Bill Finch