Oil is important, it helps you go faster and makes things last! all this old pedal, treadle, and hand crank tools need oil!
I did some homework, why do most things say SAE 30w? Well that is what they used in a UL test many many years ago.
Back around 1980 it cost 10k for a UL varience. So motor companies and companies that used them in their product don't want to spend money to get a oil approved.
So if you have something stuck, I recommend a 50/50 mix of atf and acetone, I've been mixing it up for a more than a year and it works. Haven't bought any gibb, pb blaster, liquid wrench, kroil since!