Water powered hammer
Source: Primitive Technology
I built a water powered hammer called a “Monjolo”.
I started by making a water spout from half a hollow log to direct water from the creek. This was set up in the creek and water flowed through it. The hammer was made from a fallen tree. I cut it to size by burning it at the points I wanted it cut (to save effort chopping). Next I carved a trough in one end to catch falling water. This was done first with a stone chisel that was then hafted to an L–shaped handle and used as an adze. This adze only took about an hour to make as I already had the chisel head and cordage made of bark fibre to bind it with.
To save further effort carving I used hot coals from the fire to char the wood in the trough. I put the coals in using “chopsticks” (unused arrow shafts) to transfer them from the pit. The coals were fanned or blown with a wooden blowpipe till the wood in the trough burned. Then the char was scraped out. The sides of the trough were sealed with clay to make sure the wooden sides did not burn away which would effectively decrease the volume of the trough. This was approximately 8 hours work over two days.
With the trough carved I made a hole in the middle of the log as a pivot point. Using the same char and scrape method I burnt a hole right through the log using hot coals and a blow pipe. Again clay was used to prevent wood burning where it was wanted. To burn through the approximately 25 cm diameter log it took about 4 hours and 30 minutes. Another hole was burnt in the end to fit the wooden hammer head and it took a similar amount of time.