Question about bearings

[Kevin S]

I am in the process of making new drivers for my RRSC American. In the past I have had the neddle bearings on the axels, a few times they have gone bad due to wear. I am looking at putting sealed bearings instead of needle bearings. The only bearings I can find that fit the id and the od are about .25 wide. Would it be in issue to install two sealed bearings where one needle bearing went? Also what type of fit do I want to make between them and the axel?
Thanks for any input.
Kevin S.

[cbrew]

Morning Kevin,
I commonly will place two ball bearings next to each other in the journal boxes of my locomotives and passenger cars.
as long as the journal box can float and not create a bind while running on rough track, the bearings hold up perfectly.
you want the journal box to rotate as one side is raised. this is true with every bearing type and be interesting to see if that may have caused the needle bearings to fail, just a thought, but back to your question. i do not see any issue

[Glenn Brooks]

Cbrew,

Do you machine the recess so the actual bearing shield itself is loose, or are the bearings tight? I understand the journal box and bolster, must move around. Curious about how tight the actual bearings are in the races.

Thanks
Glenn

[cbrew]

the trucks in question float in the truck frame. much like the journals on a steam locomotive. so the bearings have a slip fit in the journal box and are constrained with either a light press or in my case with the cars mechanically using a screw and washer on the end of the axle

[Glenn Brooks]

OK, thanks! Iam getting ready to machine new axles and replace all the bearings in 8 old passenger trucks. Hopefully, slightly larger sizes. So good to know.

Glenn

[rkcarguy]

Glenn, unless you've gone with a different method than using the self aligning pillow blocks, having the bearing boxes float around isn't something you want...at least don't combine the two. It will allow the blocks to swivel all over the place non-concentric to the axle. When plain, non-self aligning bearings are used in a journal box, yes I agree the outer race or box needs to float in the truck frame, or the bearing will experience a bind situation and wear out quickly.

[Rwilliams]

Long ago I was constructing the deluxe RRSC arch bar trucks for a tender. The journal box castings were to be bored out about .010 to .015 larger than the OD of the bearing according to the set of prints. I bored the journal boxes deeper and adjusted the axle for the use of two bearings on each end of the axles to make the bearings last longer. Once completed, it was easy to lift one wheel off the rail and the other three wheels still remain on the rails.

I used the cast aluminum bolsters with a small bump cast into both ends of the bolster to encourage a nice pivot point against the center casting. With the contact surface of aluminum against aluminum, I felt something else was needed. Soon the cast in bumps of the bolster were milled off and a 6-32 button head alloy screw was installed insuring a long life of truck flexibility.