And I learned how they work sitting om my grandads lap 50 years ago. Finaly I hav set up my first model engineering shop and started on a Suart 10V.
I am obsesed by details. I want to make it perfect. (However, I won't be able to achieve just that just yet). That said, I wonder why I don't see ball bearings in steam engines? I of cause understand the scale/time like miss match. Will I violate som unwritten laws if I fall for the temptation to conseal some ball bearings inside a bronze bearing cap? Will I be banned from steam heaven if I did? Would I be haunted if I showed up with the smothest running steam engine ever, with consealed ball bearings? Would Mr. Apelton turn hes medieval wrath and weaponry against me?
I agree. For a desk top model, plane bearings are easy to make in the shop and will outlast your lifetime if well fitted and lubricated. On the other hand, if you are building locomotive trucks or engine parts that will be difficult to access for maintenance, then a sealed bearing might be the best solution. Take for example a locomotive feed pump driven off the axle. A sealed bearing would be perfect in that case.
I guess it's a matter of historical authenticity versus modern technological developments. Most steam engine technology is largely a 19th Century thing when ball races were uncommon. For the forces involved when running a model or toy steam engine plain bearings are sufficient - 200 years of steam engine development proves that. There are some precedents for using ball bearings in model steam engines, e.g. the Graham Industries TVR1ABB. However, most model engineers find them unnecessary. That being said if you would feel happier using ball bearings in your steam engines then go for it. No-one will stop you. The important thing is to have fun. Happy steaming.