[somebodyy]

Hello, it's me again    I have an interesting question and I can't find an answer to it. How to make an accurate cuboid and cylinder without using any modern already accurate tools? Say you have two randomly shaped piece of wood(or clay, or stone, or any other natural material), how would you cut/shape/form them into cuboid and cylinder without using modern tools available( imagine you are on island and dont have anything that belongs to modern world). But the cuboid and cylinder you make must be acceptably accurate. for example with dimensional error 0.1 mm maximum. And yes I have done research about this a lot but dont have any solid results. I hope I made my question clear, if not please tell me to explain it with even more detail, If i can. 

[Borek]

I am not convinced the question is precise enough to guarantee any answer. What materials do you have at hand? What kinds of wood?

I am not sure 0.1 mm is possible with a wood. Perhaps with some hard kinds, but even then the size will depend on the humidity.

[somebodyy]

Well, the kind of wood doesn't really matter much. 0.1 mm is not a lot believe me ! household aluminium foil is generally 0.016 mm. seriously 0.1 is not very much. i have a copper foil that I recently bought, it is 0.1 mm in thickness and really that's thick.

well let's specify the material, say wax. yes wax, you can easily cut it. wood cutting is also possible, though a little harder than wax. so material is wood/wax/clay.  clay is also easily cuttable.

but since you are on island you don't have a knife or any other modern day tool. on island you have sand, soil (basily clay), trees (wood), wax and stones around. how would you make a 10cm X 7cm X 3cm cuboid and 5cm diameter X 17cm long cylinder out of wood ?

I hope I can make myself clear about the question    we take the precisin and accuracy we have for granted and I really wonder how humans before us made this ?

[Arkcon]

First off, what Borek: said is, that you can't have that level of accuracy (I switched words for a reason -- look them up)  for something that's soft and deformable.  You might want to switch to stone, say, rock crystal (they make nice skulls, or so I hear.)  Then, you really have to decide what is "modern" technology.  Your second one mentions not even having a knife.  That situation pre-dates early hominids.  You might as well ask how do dogs and cats build precisely fit (I switched back -- see why?) structures.

[somebodyy]

Ok I got it, it was my mistake to ask.

[billnotgatez]

Pottery wheels have been here since early Egyptian times.
Are they

without using any modern already accurate tools

I am betting a lathe has been around for a while (however crude).

[Just me being a late arrival]

Ok I got it, it was my mistake to ask

not so and chemistry history is just as interesting as well

[DrCMS]

I really wonder how humans before us made this ?

Made what and for what reason?  Why on a desert island would you need a 10.0cm X 7.0cm X 3.0cm cuboid and 5.0cm diameter X 17.0cm long cylinder out of wood?
 
In the past if two parts needed to be made to fit together very closely say a nut and a bolt 1st they made the nut and then they was hand made and adjusted the bolt to fit the nut or vise versa.  It was only later with mass production that we required multiple identical nuts and bolts to fit any other that reproducibility became an issue.

[Enthalpy]

Cubes and cylinders are not easy shapes to obtain. But balls for bearings are obtained without tools, just by tumbling pieces of steel together - and are much better round than could be obtained by hightech, <<1µm.

Telescope mirrors are made spherical by amateurs (before further processing, often to paraboloids). This goes by grinding against each other two pieces of glass with a regular but not metrologic movement, where one piece gets concave and the other convex. The accuracy is like lambda/20 or 30nm.