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    Re: Bygraves
    From: Bill Morris
    Date: 2009 Jul 16, 19:59 -0700

    Frncis has made a great start. I think it is possible to get something looking 
    even more like the original. 
    Ronald van Riet gives the dimensions of the tubes in millimetres, but I think 
    the original outside diameters would have been imperial sizes:
    2 1/2 in; 2 5/16 in; and 2 1/8 in. Nowadays, the only stock imperial sizes 
    that are near are 2 1/2 and 2 1/4 in.  There is a wide range of tube wall 
    thicknesses, so it will be possible to get to the required dimensions by 
    turning and/or boring.
    The hexagonal top and the fluted base will be easy to make if a suitable material can be sourced.
    I suggest we make a start with the simplest item, the Bygrave, and graduate to 
    the more complex German instrument. I can obtain suitable aluminium tubing 
    for only the two larger diameters - and only in 5 metre lengths. If someone 
    out there can send me 10 inch lengths of tubing with the right inside and 
    outside diameters to reach the required diameters, I would be happy to make a 
    start and pass the results on to the "scale fitters". This could prove the 
    concept as well as setting up a cooperative to supply those who don't own the 
    necessary machine tools.
    Bill Morris
    New Zealand
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