[time-nuts] Greek clocks - planets rather than seconds
Peter Torry
peter.torry at talktalk.net
Mon May 11 15:38:07 EDT 2015
Hal,
Gear wheels have been cut by hand for many a century. A simple dividing
head made from wood and fixed to a mandrel would index a blank wheel and
allow the teeth to be cut by a saw and then rounded up to a cycloidal
shape with a file. As time progressed shaped files were used and later
simple fly cutters with the cycloidal shape.
Files were made by hand in a similar way as that are made today. Once
the correct material was chosen, originally iron and later steel, a
blank was shaped and the teeth cut using a chisel. The file would then
be hardened by heating and quenching followed by straightening and
warping before it set. As with most tasks machines either speed up the
process or take the skill out of it. As an aside only use new files on
brass until they have the edge taken off them then they can be used on
harder materials.
There is somewhat more to the above but it would take up too much bandwidth.
Regards
Peter
On 11/05/2015 00:32, Hal Murray wrote:
> Michael Wright talking about the Antikythera
> http://www.the-eg.com/videos/michael-wright-antikythera-resurrector-eg8
>
> The video is 1/2 hour. I thought it was good. He's a colorful speaker.
>
> Anybody know how they made gears back then? Or machinery in general? What
> did they use for a file? How did they make files?
>
>
> The Computer History Museum is having an event:
>
> May 13, 2015 10:30 AM
> Secrets of the Antikythera Mechanism
> http://www.computerhistory.org/events/upcoming/
>
> In 1900, sponge divers off the coast of the tiny Greek island of Antikythera
> made an astonishing discovery: the wreck of an ancient Roman ship lay 200
> feet beneath the water, its dazzling cargo spread out over the ocean floor.
> Among the life-size statues and amphorae was an encrusted piece of metal,
> which after nearly a century of investigation, is finally revealing its
> secrets....
>
>
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