I love my ShopSmith, it can be a great tool/tools if you take a little care to get it setup well. That being said, you likely won't find much love here for the ShopSmith or other similar multi-purpose tools.
As far as lubrication goes, the officially recommended product is paste-type furniture wax such as Minwax. Get all the dust cleaned off and then apply the wax liberally to the upper tubes, tables, etc.
As far as uses, other tools. The shopsmith makes an excellent wood lathe, a good drill-press, and a reasonable table-saw/disc sander, etc.
If you have it, the bandsaw is very good as well.
The jointer is good quality, but the 4" size can be limiting for some applications.
If I were buying any additional tools, I'd probably go for a good table-saw, a good cross-cut mitre-saw, and a thickness planer, in addition to the ShopSmith bandsaw and Jointer I already have.
If you haven't already found it,
https://www.shopsmith.com/ is still very much in business and they will cheerfully sell any and all spares and parts you might ever need.