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I'm making a human society that has a lack of metal ore and no knowledge of metalworking at all. However, industry must still continue, metal or not, so I'm thinking about a water mill made out of hardwood. Would that be possible? Or does the lack of such durable materials doom this option before it can even begin?
Edit: As a comment suggested, I would like to clarify that I am worried more about the Long Term use than the material difference.
It is very possible. It's been done. The wheel itself can clearly be made out of wood, as many are even in societies that have metal. The axles and gears that transfer the rotational energy are usually wood too, though sometimes with metal fittings or casings so that they will wear down and need replacement less quickly. The milling surface itself can be made out of stone. The biggest challenge might actually be the lack of nails. Instead, wood pieces could either be lashed together with rope, or holes can be drilled in each and then a wooden pin put through.
Japanese built water mills without any metal. The Japanese are masters of construction using just wood and wood joinery.
Without metal you're limited to using the mill for basic things like flour grinding or water pumping.
Water wheels were often used to power wood cutting, a blacksmith shop or other industry shops. These often relied upon metal.
Yes, lignum vitae wood was used as shaft bearings in the first hydroelectric plant and also on the first nuclear sub. It's waterproof, very dense and self lubricating.
Using this primitive design makes it easy to build a reliable impact-type (trip hammer) mill without any metal, not even a small metal nail:
Author STA3816
https://commons.wikimedia.org/wiki/File:Watermills_at_Onta_Pottery_Village_02.jpg
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From Wikipedia (CC-BY-SA):
A water scoop is a simple hydropower machine–that is, a machine used to extract power from the flow of water. Unlike a water wheel it operates intermittently, like a seesaw: A container (a bucket or cup) at the end of a lever is filled with water in the upper position. The container side becomes heavier, and so the lever with the filled container moves downward, which may be used to operate a machine drive. In the lower position the container is emptied, and the lever moves back into the upward position.
Because of their inferior efficiency compared to a water mill, water scoops are less common, and have been used in the past mostly for applications where linear motion is required rather than rotation, for example hammers in smitheries, saws in sawmills, and stamp mills in mining. They are also used for fulling and, nowadays, to operate animated sculptures in fountains.
Assuming you have flint or obsidian to make cutting tools, definitely yes.
In the absence of metal, you will learn a lot about how to deal with the limitations of wood.
I can no longer find the source, but I have read about gearing used in windmills; the teeth are replaceable of course, and ideally made from apple wood, seasoned nine years, for maximum hardness. (Another subtlety was mutually prime tooth counts , e.g. meshing 19 teeth (not 20) against 40, so that the teeth wore evenly. Bearings run too slow to overheat, as long as they are lubricated with fat or wax.
As others have mentioned before, it is possible. My biggest concern with such a build is related to the tools required. If you cant use metal saws and chisels for example, the task becomes a whole lot harder, but still doable.
Answers so far have focused on real-world all-wood construction techniques, but a world short on metal ores may well develop advanced ceramics at a lower overall tech level than we did.
Things like ball bearings can be made of ceramics even at only moderate tech levels.
The relative hardness of ceramic bearings results in increased durability over comparable steel bearings. Ceramic material does not rust, unlike steel, meaning exposure to moisture is less of a concern, particularly for full ceramic bearings. They require less lubrication and do not suffer from pitting.
However, there is a risk of chipping, particularly where they are located in areas that are susceptible to water or grit ingress. So whilst ceramic bearings can last between 5 and 20 times longer than steel bearings it is important that they are fitted and maintained correctly.
Im not sure if this is what you mean, but wood is a very standard way to build a water mill.
If you mean not putting the wood together without nails, seems that some where used to be ensambled by pressure by leaving some little wood connections, even though i can't find a suitable reference for the ancient construction.
If duration is your problem, since it was used by our ancient civilization, i would say that they last long enough as long as you make maintenance (like old boats that where treated with resin from trees or wax in order to travel the ocean)
Some considerations others have not addressed: Suitable timbers are Greenheart, Ekki , and Oak (which is not as good as the other two).
It is five to seven times harder to work hardwood with metal tools, compared to common softwoods. It is even harder to work Lignum Vitae. To work using only stone and flint tools, making a mill wheel could be a lifetime's achievement.
It should be remembered that in medieval times burning the wood to work it was a useful technique, many holes and notches being made with red-hot pokers because drills were hard to make.
Given the difficulty of working timber without metal tools, It would probably be easiest to weave as much of the wheel as possible from willow/sallow, ie. use wicker baskets, which could be waterproofed by painting them with lime to fill the gaps in the structure.
