Does anyone know what a journal bearing is? thrust bearing?
Is one of these types like a rotating collar or sleeve in lieu of individual ball bearings?
Rolling in it,
- Jinx
Journal bearings are radial bearings.
And here you will see “thrust bearings”
Journal bearings are indeed rotating collars, with a controlled oil film replacing balls or rollers. The friction between the oil and the metal pulls the oil into what would otherwise be the contact region. The pressure of the oil film provides some centering load.
Thrust bearings are any bearings that take their load primarily along the axis of the rotating part, rather than the radial direction. Some take load in both directions, like the tapered roller bearings found in opposed pairs on car axles.
Not necessarily true.
Journal bearing is also a generic name given to a type of “cheap” needle style bearing found in non-precision applications like wheelbarrows, casters, etc.
They are not quite as common nowadays as they used to be but they are still pretty widely found.
“Thrust” bearing is an extremely generic term. Elvislives did a pretty good job of describing them. As Elvis mentioned, most bearings take loads in some extent in both directions. For example: As long as a “thrust” load isn’t all that large you can generally use a radial ball bearing as a thrust bearing. For example, a Conrad radial ball bearing (which is the style that most people think of when they see a “ball bearing”) will take upwards of 30% of its entire load capacity as a thrust load. Since even a “small” bearing can take hundreds (if not thousands) of pounds of load, since these are “cheap and plentiful” they are often used.
General types of thrust bearings (and for some of these there are differnt types yet):
Ball-thrust
Needle-thrust
spherical thrust
cylindrical thrust
plain thrust (like a washer)
And I am sure a few more I have missed. If you have anymore questions, feel free to ask. This is something I actually know a bit about. 
This is a boffo thread.
I want to know more, bernse and everyone else, but frankly some of the written descriptions thusfar have been pretty opaque. Can we have more pictures like Philster’s Discovery.com link? Or easier to follow written descriptions?
Thanks.
PS – I was very impressed during my tour of Hoover Dam to learn that their enormous vertical turbine shafts – I’m talking big, baby big – spin on a paperthin layer of oil that is pumped (???) between the bottom of the shaft and its housing; the bottom line is that this huge chunk of metal – the shaft – spins around like crazy year after year and never even touches the metal housing that holds it. Ergo, no wear on the shaft or housing even after decades of use. Wow.
stuyguy, I would guess those rotors were running onKingsbury floating-plate thrust bearings. Those use the journal principle (squeezing a film of oil), except on the ends and not the sides.
This is a good introduction to types of rolling-element bearing designs.
And here is the part of that post that disappeared into cyberoblivion somewhere:
…Kingsbury floating-plate thrust bearings. Those use the journal principle (squeezing a film of oil), except on the ends and not the sides…
Go through www.skf.com as well. Its been a while since I have been there but I think they had some really good info on rolling element bearings as well.
Anything in specific you want discribed? I’m kinda leery doing them all 
PS - I’ve been in the bearing industry for the past 10 years or so.
I tried this last time; didn’t work.
Here
is a good intro to rolling-element bearing design.
Here’s bit of a tangent after all that excellent information. When a friend of mine was in the US Air Force, a pompous officer dressed him down, screaming,“Where’s your military bearing?” From that time forward, he wore a small ball-bearing set, complete with Federal Stock Number, on his dogtag chain. No one ever asked him that question again, but he was ready.