Sorghum Mill Repair

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

John

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?

Can you post a picture at

in the dropbox? That would make it easier to to describe a possible repair. Use some sort of scale in the picture, such as a tape measure, ERS

I think you might be on to something here...most factories that did that kind of steel casting at the time were mainly doing railroad stuff. Possibly it's a railroad sized journal formed on a machine instead? Maybe with some rough sizes listed someone here with an old RR book can match it to a standard journal and material for the shoe.

Koz

Any chance the taper is just "wear"? Maybe good needle bearings would work instead of ball bearings - although the bearing bronze mentioned below would probably give you long enough life provided sufficient lube was available. Ken.

I know that it is claimed that cast iron is supposed to work well as a bearing for hardened steel.

As to Babbitt metal, I was unable to locate the PDF scan of an old book called "The Magnolia Metal Bearing Book", as all of the links to it seem to be dead. I had a copy of it once and it's since been lost, but I do remember that there are at least two kinds of Babbitt Metal, for different kinds of applications. If I remember correctly you would want the type of Babbitt metal that has no lead in it. I think it is an alloy that is mostly tin, antimony, and copper.

Oh, wait! I just found a working link:

From what little I know about this application, any lubricants must be "food grade" materials. They curently use a grease.

There are no signs that there was ever any other lubrication system.

John

No, I don't think the taper is from wear. Both journals are too uniform, while the bearing retainers have significantly different wear patterns. Just no room for ball or roller bearings. John

Thanks the babbit info was real interesting.

After looking around for bearing materials, I thought of two other possibilities. Linnen filled bakelite and UHMW. I believe the bakelite has the compressive striength, but I am not sure about the UHMW.

John

It doesn't sound like you have the room, but any chance of using wood? My father used hard maple boiled in oil, then greased for axle bearings on his levee rollers. These were field implements consisting of a concrete spool of about 2 tons with a 1-1/2" axle and heavy angle iron frame. They were pulled behind the "push" which formed the levees in rice fields. He tried roller bearings, but they failed within one season. The maple would last for over a decade. This was a high pressure, low speed, very dirty application.

Pete Keillor

UHMW will not work at those pressures. It will tend to cold flow and/or reach it's yield strength quickly.

The person who posted about wood bearing has an interesting idea. Those have been used in certain industries for years. Although probably not the ideal solution, it may get the machine up and running more quickly so that your friend has time to make final decisions about the bearings. Heck, you may find that the wood lasts and lasts.

Koz