From around 2010 through 2012, I worked closely with Pat Delaney to produce construction models and drawings for his Concrete Lathe idea - a method for building a lathe out of ~$50 and spare parts that you might have lying around.

I attended the Open Source Hardware Summit in NYC in (I think) 2012 to help Pat present the Concrete Lathe project.

In 2016, someone finally built one (here is the Instructables article).