Roy, I think you carbon steel tools would be at least 50yrs old, could be double that.
My first thread cutting tool was(is) a bit of a 5/16" square file, it did its job OK, and is still in my collection of lathe tools, even though it has not been used for over 20yrs. I know of some older lathe opperators who swear by carbon steel, saying that you can't get as good an edge on HSS, and now its the same again, but with carbide, and HSS, but I think each tool for its own use. If you have time to go slow, carbon steel might be quite OK on a mini lathe, you would sure find out how to sharpen tools. Ian S C