On 17/03/2015 08:02, scott wrote:
>> Not if you are measuring it in cubits Otherwise that is a terrible
>> tolerance. For instance the first breakthrough from the English to
>> French side of the Channel Tunnel was 358 mm out over 22 Km.
>
> That's cheating though, that's like making your 10 metre bit of steel to
> a ± 5mm tolerance, then filing it down to fit :-)

It did say later in the article that that tolerance would have been 
unacceptable for a running line.
I didn't mean to imply that it was good. Although I think that it is. 
;-) The horizontal miss was less than 60 mm.

It is amazing the fine tolerances people can work to.

-- 

Regards
     Stephen

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