# 8" Junior Spindle Bearings Advice



## Giovanni (Sep 13, 2012)

Hello,
i am acquiring a 1932 8" Junior lathe and the bearing caps and spindle bearing surfaces are worn to the point of needing restoration. I plan to keep this lathe for many years and would like to have someone line-bore the bearing caps, turn down the spindle bearing surfaces and install bronze bearings. These lathes never had any bronze bearings, only hardened spindle bearing surfaces spinning in cast iron bearing caps. Here is the link to Tony's lathes, showing examples of the Junior.

http://www.lathes.co.uk/southbend/page3.html


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## Tony Wells (Sep 13, 2012)

Sounds like the makings of a good plan. Line boring the headstock will be a little of a specialty, given the accuracy desired. I'd recommend you study the larger lathes' construction to see how closely they can me mimicked. As far as the spindle goes, I'm not sure if they are induction hardened thru, or simply case hardened. I'd be very careful removing much material from the bearing journals.

If you knew someone with a large enough horizontal mill, you should leave the headstock mounted on the bed for the line boring. If not, I'd seriously think about how it was to be mounted on the mill table. A faux copy of a short section of the lathe bed would likely give more stability and similar stresses so that the bores would be true after remounting on the original bed. Or perhaps consider lapping or scraping them after boring a bit undersized. You could be in for a few headaches if the boring doesn't go well.


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## Giovanni (Sep 13, 2012)

Tony,
Thank you for your brilliant reply.
I agree with you about the headstock being line-bored with the bed attached. This would give the truest results. The thing that is going to be tricky is how to fabricate the bronze bearings.

Kind regards,
Giovanni


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## Tony Wells (Sep 13, 2012)

Back in the "olde days" babbit was the material of choice for many machines, and it was poured in place. I would think that a cast bronze piece could be machined to suit. Or even a bronze hollow bar of bearing grade could be made into a bearing. The most difficult part would be the mechanism or design shape to lock it into the headstock to prevent rotation. A machined slot and mating key might be considered. Or take a look at automotive crankshaft bearing inserts. I might even consider using them for this. They are keyed, and have oil grooves and holes in place already. Certainly they are robust enough, considering what they handle in an engine. As a plus, not the whole set, but one or more of the bearing inserts have flanges designed as thrust bearing surfaces.


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