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

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Subject: Re: [Leica] A Tonne?
From: Henning Wulff <>
Date: Sun, 24 Mar 2002 13:18:21 -0800
References: <>

At 7:29 AM -0800 3/24/02, Dennis Painter wrote:
>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. ;-)

I assume that your reference to 10,000 tons is regarding Leica's 
production? If so, I think your decimal had some slippage. I believe 
the amounts in question were 10 tons/yr, or about 2.5 cubic meters.

- -- 
    *            Henning J. Wulff
   /|\      Wulff Photography & Design
  |[ ]|
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