Well, They're all different. I have two, one was my Grandmother's first machine. It's one of those wrought iron ones. There are little holes here & there to put "1" drop of singer oil in it. 3 in 1 oil works too though.
My second machine is a Singer portable and does all kinds of fancy stitches but the one that still sews the best is the old antique one!
Try Goggling for manuals for your model. That can sometimes turn up results.
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