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    Wrapped Bygrave
    From: Wolfgang Hasper
    Date: 2010 Jan 17, 17:41 +0100

    Making a "real" cylindrical slide rule is quite
    complicated, main obstacles are
    - tubes needed to specific uncommon diameters
    - need for precision in diameters
    - precisely fit the scales to the circumference of
    - locking mechanisms required ;o)
    and surely more.
    The flat bygrave is a great step towards a cheap and
    simple implementation of the principle. While it is
    ideal for storage it can be hard to use when no desk
    is available or wind is present.
    As an experiment I printed both flat scales on film,
    punched them on both short sides and wrapped them
    around a pipe, using elastic ribbons to have some
    tension on the film. (see photos)
    Works good and has enough friction to keep any setting.
    No need for any particular tube diameter. No need to
    precisely align scale ends either.
    If needed even a cursor can be drawn on the tube. The
    two film scales slide together if you want.
    For this first model I had to use 100mm sewage pipe as
    core because the scales were made "landscape"
    not "portrait".
    Using rearranged scales for "portrait" A4 will allow
    for a handier 70mm pipe.
    Within the pipe there is again enough space for
    emergency documents, pens, paper...
    While I do have the fortran programme I cannot handle
    it. If any of the scale producers were interested in
    making a rearranged version I would be happy to make
    more experiments.
    What do you think? Can the advantages of the tubular
    setup (handling) and of the flat printout (ease of
    production) be combined this way?




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