John Normile wrote:
On Fri, 10 Sep 2004 02:30:50 GMT, Ken Sterling (Ken Sterling) wrote:


I have a friend who is trying to repair an old sorghum mill. The
major problem with this machine is the condition of the bearings.

This machine has three rollers that crush the cane. Two are
adjustable and a half bearing shell is used to adjust pressure. One
remaining half bearing shell fragment appears to be made from bronze.
It looks like someone has tried to repair these bearings in the past
by pouring a lead or babbitt bearing. The poured bearing quickly
failed under load.

Has anyone had experience repairing these mills? And is there any
information available on the bearings used with these machines?

Any leads will be appreciated

John Normile


I think a lot of older equipment using pressing rollers were designed
this way, but you may be better off trying to convert it to ball or
roller bearings - else you may have to "make" your bronze bearing
halfs to replace the originals.
Ken


My friend looked into converting it to ball bearings, but there
doesn't appear to be enough room. And one of the roller journals is
made with a taper. We assume that the taper is there to handle
thrust in the machine.

The bearing system is unique, at least to me. There is only one
"half shell" type bearing on each journal. This is on the side that
takes the pressure from squeezing the cane. The block that retains
the bearing is similar to an automotive crankshaft bearing cap. But
instead of being about an inch or so thick, it is about 5" thick.
And the diameter that holds the bearing shell is recessed down into
this holder block. A lip of material then retains the shell and
prevents it from turning.

None of the original bearing material is left. Any idea what the
preferred bearing material would be for this application? I am
assuming that a bearing bronze would be the choice for this
application. This is a low speed, high pressure application

I'm gonna go out on a limb here, because I'm
not an expert on these things.

I'd design an oil bearing system. Duplicate the
original bronze bearing as well as you can then
fit it with several small oil passages and a way
to presurize the oil into them. The goal is to get
the journal to positively ride up on a layer of
oil. This is how lots of big, slow high pressure
bearings work.

Alternately, you could just try to duplicate an
old-style railway journal bearing. As near as
I can remember, it's nothing more than the journal,
a half shell bearing on top and the journal sitting
in oil at about half it's diameter high. Now that's
pretty much what you've described, but without the
oil bath. Is it possible that someone removed
the oil containers years ago?