As someone who used to work out ratios/size etc cut gears amonst other things I`m left completely gobsmacked
http://www.bbc.co.uk/iplayer/episode/b01hlkcq/The_TwoThousandYearOld_Computer/ (http://www.bbc.co.uk/iplayer/episode/b01hlkcq/The_TwoThousandYearOld_Computer/)
Watched this the other day as I love history.
Amazing stuff. Clever guys were those Greeks!
There is also a good History Channel programme on this subject as well as dozens of books (of varying accuracy) detailing this fine device.
Due to the location of the wreck and several multiple wrecks found nearby over hundreds of years I believe there was still some academic discussion about the definitive dating of the Antikythera Machine.