More progress

[marinesteam]

Quoted from FAG bearing website

Babbitt, while not as modern and as widely used as the ball bearing, is a genuinely great material for use in a lot of mechanical applications. Lasting the lifetime of the owner, Babbitt bearings demand slight care. Ball bearings do not last as long as Babbitt.

For what it's worth

Ken

[S. Weaver]

A properly designed babbitt bearing can be superior to roller, needle or ball under a wide variety of conditions. It's only downside is the labor-intensive nature of its lubrication. As with so many things, it all comes down to how much a human being is involved or not involved.

Those are lovely con rods. We look forward to the rest of your engine work.

[Lopez Mike]

I wouldn't THINK of changing the bearings on a traditional design from babbit or bronze to an antifriction type, whether ball or roller. I've poured more babbit than you might think. I spent years rebuilding Ford A and T engines and fixing up old drag saws.

I love watching my friends fool around with wick oilers and lovingly filling little cups. But I also love watching my partner mess around in her garden. Do I like doing either? Not really.

That said, any engineer given a blank sheet of paper would be deranged to choose anything but a roller/ball bearing for rotating motion at low to moderate speeds. Automobile crankshafts are a complicated compromise.

The last bastion of sliding friction in modern design is in large telescopes where extreme rigidity and an no static friction are everything. Moving 5000 tons at one revolution per day is a rather specialized application!

I'm busier than the proverbial one armed paper hanger when I'm out steaming. Any part of the power plant that needs no attention is a welcome passenger.

Mike

[fredrosse]

In the utility industry, large fans are used to push around the stack gasses from coal fired boilers. The US industry specifies ordinary ring oiled sleeve bearings for almost all of these fans, be they centrifugal type or axial type.

For the axial fans, the normal manufacturer's practice is to use roller type bearings, these can take higher loads, but need to be replaced every 5 years or so. In the US we even specify sleeve type bearings for the large axial fans, ranging up to about 15,000 horsepower, 900 RPM machines. That is because the sleeve type bearings will typically last for 40 or 50 years without replacement.
The fan manufacturers manage to modify their standard designs to use sleeve type bearings to get sales in the US.

[S. Weaver]

Every time I hear a Class 1 railroad operations official get hysterical about hosting plain bearings, I like to remind him that the traction motor gears on all of his locomotives are spinning on plain bearings. The reaction is priceless.
Try and buy a wheelset right now. Sandy immersed hundreds of rail cars and coaches on the East coast. Every wheelset had to be changed out and the bearings reconditioned. In plain bearing days, one would wipe the journal off and pack new waste. We have made social decisions about labor, resource allocation and how we assume we ought to spend our time. It's not superior engineering.

[Lopez Mike]

All very fine. But people take CARE of those bearings. My 1990 Ranger pickup has 198,000 miles on the original wheel bearings. And all of the owners (including me, alas) have been dolts about maintenance.

On the other hand my South Bend 10H has a plain bearing head headstock. It has not worn enough since my dad bought it new in 1946 to allow me to take out a single .001" shim from either side of the caps. But I use special oil and it goes through a nice felt filter and is recirculated and I fuss over it.

Given the same level of care, like nada, I'll take a roller or ball bearing.

My engine needs an oil cup to feed the cross head and one to feed a slinger arrangement for the con rod big end. Just enough to make me look like a 'real engineer' at the dock with people looking on. It's the second job I delegate right after the helm!

Yes, beautiful con rods. As said in my earlier post, I love to watch other people work. I can do it for hours.

Mike (AKA Mr. Sloth)

[DetroiTug]

Almost all the early (before and after 1900) steam automobile engines used roller ball bearings on the crank and lower connecting rods. From my reading it appears George Whitney designed the vertical double simple engine that everyone then copied; for the Mason regulator company. Then Stanley built it, then Locomobile, et al... Ball bearing supported crankshafts continued on until the end of the steam car era. To almost 1930.

-Ron

[S. Weaver]

All very fine. But people take CARE of those bearings ...

Mike, that's my point. As my dad used to say, "The problem nowadays is between the ears ..."

We'll drop all that and admire Ken's con rods.

[marinesteam]

It just goes to show that there isn't always a clear cut answer to every engineering problem. Many factors need to be considered and that often points to a "best" solution but in many cases several solutions may be appropriate. More parameters can be considered to further extract the "best" solution but often one stops when a solution that works is found.

Ball bearings are often not an appropriate choice in every application. Emergency turbine blade mounting bearing are a good example of this. These devices sit idle for long periods of time without any maintenance but have to be ready to go at a moments notice. A particular set of turbine blades in these generators are mounted on bearings that allow the blades to rotate in order to change their pitch and adjust the flow of heated gases through the unit. The service temps are too high to allow grease to be used in the bearings so the bearings must be un-lubricated and the gases in the area are also corrosive. The combination of these factors cause metallic ball bearings to pit which does not allow the blades to rotate as freely as they need to or in some cases seize entirely both of which will cause a failure in the generator unit. The solution is to use a high-temp compatible plastic plain bearing. And these bearings are also less expensive, weigh far less and take up less room than a ball bearing.

Hammer mills and large stamping presses are also places where plain bearings are still a more appropriate choice than ball bearings. High impact forces and partial rotation reciprocating motions are still service areas that ball bearings are a poor choice in.

But this conversation wasn't really meant to be about the merits of ball bearings over babbited ones. You must remember that ball bearings especially for heavy loads were still in their infancy during the late 1800's. That alone makes the choice of plain bearings a more appropriate choice for this engine. I am interested in getting some hands on experience with some of this "old" technology. That's why I am a steamboater and not say a race car enthusiast. I deal with complex mechanical and electrical devices in my daily work life, doing it the simple way gets me away from this but still lets me play with machines.

Now back to our regular scheduled programming......

Ken

[DetroiTug]

It just goes to show that there isn't always a clear cut answer to every engineering problem. More parameters can be considered to further extract the "best" solution

Hi Ken,

Very true. Also, what's best for or suits them and their project. That's the beauty of this "hobby", not everyone is doing the same thing. Which is better? Whatever one likes and works.. Ball bearing or Babbit? I'd take either.

Your engine is going to be beautiful once finished. How were those rods constructed? Are they a weldment or casting?

-Ron