I don't know which is the best tool I've ever acquired for sure.
I can't decide between my small 8x19" Jet lathe or my 1950's era South Bend vertical knee mill.
Click to view attachmentIf I have to choose just one, it's the lathe. A lathe can be used to machine all the parts needed to reproduce itself or even a mill (possible in theory but very difficult in practice). So I guess I have to go with the lathe.
Click to view attachmentThe lathe makes modification of screws, bolts, washers/spacers, etc., so simple that I simply can't imagine living without it after having it for the last 20 years or so.