The Primitive Technology guy builds a water-powered hammer

The fellow in Australia, who makes tools and shelters from his bare hands and natural materials, is back with a new video. This time, he made water-powered hammer. It's basically a log (hollowed out by fire) that pivots up and down when it receives and empties water from a stream.

This is the first machine I've built using primitive technology that produces work without human effort. Falling water replaces human calories to perform a repetitive task. A permanent set up usually has a shed protecting the hammer and materials from the weather while the trough end sits outside under the spout. This type of hammer is used to pulverise grain into flour and I thought I might use one to mill dry cassava chips into flour when the garden matures. This device has also been used to crush clay for porcelain production. A stone head might make it useful as a stamp mill for crushing ores to powder. It might pulp fibres for paper even.