In article ,
steamer wrote:

--I'm having a little trouble visualizing the problem so take my
suggestiong with a grain of salt but could you not blacken the shaft with
lampblack and pour a babbit bearing in place?

'Fraid not. This is joints in hydrualic construction machinery - steel
pins running in hardened steel bushings is typical construction. If the
bore for the bush is not hosed, maintenance is pretty simple, for
moderate values of simple - yank pins (swear), remove bushings (swear
more), new bushings (and pins, if needed) (swear a little, but most of
the swearing is for removal). Keep it greased...

If you were to pour up a nice Babbit bearing, then go use the machine,
it would be: hook onto a rock, squeeze the Babbit out like toothpaste.
The joints would have to be made much larger to get the pressures down
where bearing materials like Babbit hold up.

Very low velocity, very high pressure, plus a filthy and abrasive
working environment.

For a vague idea of what's involved, consider that my bucket is rated to
produce 9000 lbs of force at the edge - which is about 2 feet from the
pivot. The cylinder is less than a foot away on the other side, so it
has to be putting 18,000 lbs into the bucket pins, and the pivot itself
gets some large force that's not immediately obvious, but might be as
much as 27,000 lbs...on a pin that's about and inch and half diameter,
with the bearing on the bucket only 1-1/4 inch long on either side of
the dipper-stick.

--
Cats, coffee, chocolate...vices to live by