
How an hourglass is made - raphar
http://kottke.org/11/04/how-an-hourglass-is-made
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pedrokost
Can someone explain how they manage to 'calibrate' the hourglass to 60seconds
(or whichever time they choose)? Is it done by trial and error or they can
make hourglasses so precisely that they the width of the slit precisely
determines the time-length? I doubt such precision can be achieved in manual
labor.

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bradleyland
The orifice size needs to be fairly consistent, which requires talented
artisans, but some variation is unavoidable, so they have sands of different
coarseness for varying sizes. The timing is calibrated by adding/removing san
[1]. Scroll down to "The Manufacturing Process" in the footnote link.

1 - <http://www.enotes.com/how-products-encyclopedia/hourglass>

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guelo
Wow, that looks like a lot of equipment and labor for a product whose market
can't be very big.

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jergosh
Prices start at EUR 9500 so it must be a niche product ;)

