Archived posting to the Leica Users Group, 2002/03/24

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Subject: [Leica] A Tonne?
From: Dennis Painter <>
Date: Sun, 24 Mar 2002 07:29:59 -0800

How much is a tonne of Leica glass?

Well 10,000 metric tonne really.

Which is 10,000,000 kilograms

Per Schott Glass Product Specification:

N-LAK34 runs 4.02 g/cm3 or about 4000 kilograms per cubic metre

(LAK34 is just the first optical glass product sheet I found and this
stuff is really heavy compared to ordinary glass!)

So 10,000,000 kilograms would be 2,500 cubic metre of glass.or 74,818
cubic feet.

That's a pile 10 by 10 by 25, or 10 ft by 10 ft by 748 feet high. That's
a lot of glass, a lot of lens elements.

Wasteage in production has been mentioned.  It seems unlikely that a
significant number of production melts would be unusable. It is the
nature of manufacturing processes to put in place procedures which will
result in high yields.

I do believe there is a significant amount of glass "consumed" in the
production of a lens element. Cutting shaping and grinding from a blank
to the final element have to remove material.

I don't know how much but if only 25% of the material ends up in the
element our pile is still mighty big.

At this point I wonder if 10,000 metric tons mentioned in Leicaview is
an accurate transcription or translation of the interview with Norbert
Meinert. Perhaps someone knows a way to verify.

Or maybe I made an error in calculation. ;-)

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