From No Tech Magazine:
The Concrete Lathe Project
"Metalworking lathes are necessary to the production of almost everything but are very expensive. In 1915, special lathes made from concrete were developed to quickly and cheaply produce millions of cannon shells needed for World War I. Lucien Yeomans, the inventor, won the nation's highest engineering award for it but sadly the technique was almost forgotten after the war. We re-discovered it as a way to quickly make inexpensive but accurate machine tools for use in developing countries and in trade schools and shops everywhere."Also at No Tech:
Pat Delany developed a metalworking lathe design that uses concrete parts cast in wooden molds to achieve high precision at a rock-bottom price of $150. Find the detailed building plans at Make Projects. Also check out Pat Delany's low-cost DIY machine tools (such as a hand-powered drill and a treadle-powered generator), all built from recycled parts.
The Future Will Not Be Like The Past
..."Not only will there be a wider gap between the places with the highest and lowest technology, there will also be a wider gap between the highest and lowest technology used by an average person. Already there are African villagers with cell phones. In 20 years you may be living with a group of friends in an abandoned suburb, burning scrap wood for heat, growing open-source genetically modified sweet potatoes, and selling brain time to the dataswarm to gain credits for surgery to install a neuro-optical interface so you can swap out custom eyeballs."
Quoted from Ran Prieur's blog.