Anyone else keep an eye open for old tools? I picked up an OLD circular saw for $20

My guess is if it takes oil it would only be a couple of drops on the saw side bearing. Maybe 3-in-1 or some furnace type oil. But I don't know for sure. Is there a button that locks the shaft to ease blade changes?

No, I don't believe it does have a button. I have it in the box in the bed of my truck. I am going to bring it in on break and clean it up. I will get some more pictures then.

There is a plug on the backside (between the handle and the blade) that looks like a plug for the gear box? I will get some pics of it too.