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    Poor's "Line of Position Computer"
    From: Dave Walden
    Date: 2008 Oct 3, 14:54 -0700

    To make a reduced scale replica of Poor's Line of Position Computer:


    1 Print out the base .pdf file


    2 Cut 1 inch off the top and 1/8 inch off each side of the base


    3 Push a thumbtack through the center of an 8 1/2 x 11 inch piece of cardboard


    4 With a pointed object (e.g. push pin) put a hole through the center of the base print out


    5 Print out the circle with straight-line .pdf file (attached) on clear transparency film (old fashioned now, but still available)


    5 Cut out outside the printed circle


    7 Make hole through center of the clear circle (found by laying on print out of the base) using your pushpin


    8 Put the print out of the base on the thumbtack and attach to the cardboard (double sided tape works well)


    9 Put clear circle on the thumbtack (the film may have some curl, place so the middle is high i.e. so when the middle is pushed down, the outer radii will be pressed against the cardboard)


    10 Cut out "appropriate" size rectangular arm with line (from film with circle)


    11 Make small hole on the line at one end


    12 Use hole punch to make a larger hole on the line at a distance from the small hole about the radius of the circle line, but less than the radius of the cut out circle


    13 Put a small piece of clear tape face down on this larger hole (this simulates Poor's mechanism to clamp the arm to the circle)


    14 Put the small hole on the thumbtack (so sticky side of tape is down on circle)


    15 Cut the thumbtack off, leaving "enough"


    16 Cut "enough" eraser off the end of a pencil


    17 Use pushpin to start a hole in eraser, then put eraser on thumbtack


    18 Mark circle and arm in some manner to aid setting and moving


    19 Compute (using directions from Poor's text found on Google books)


    see previous posts for the pdf and photo of an example

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