Ben Roth asks about noisy pedal linkages [230609 MMD], a common
problem on well-used pumpers. For the heel end of the treadles,
I generally use hardened spring pins.

The holes in the fixed brackets are typically egged-out and should
be returned to roundness, preferably on a milling machine so they
can be held tight. Use a bit sized for a non-interference fit for
the next larger standard spring pin, so that the pin turns in the
bracket (and can be oiled), not in the wood.

Choose pins at least 2 inches long, longer if available, so as to
form a long, non-rotating connection in the wood (which may have
to be reamed slightly undersized for the pin).

For other metal-to-metal joints, I typically use Oilite sintered
bronze sleeve bearings, a good selection of sizes of which is
usually found at "real" hardware stores such as Ace Hardware, but
they can be pricey.

John Grant

 [ https://www.acehardware.com/ 
 [ https://oilite.com/oilite 
 [ https://www.grainger.com/category/fasteners/pins/spring-pins 
 [ -- Robbie