This is my week for mystery slide rules! This one arrived today, and in the materials used for its construction it is unlike any other slide rule I have ever seen…
Click on the thumbnails at right to get full-size (300 dpi) scans. They are JPGs this time, so they’re not quite as huge as the PNGs I subjected you to yesterday…
The main mystery is this: who is the maker? A. F.? This rings no bells with me…
The bottom photo shows the slide set up on edge to be scanned. This shows you the bizarre construction of this rule. What you’re seeing is the ends of metal bars, roughly rectangular in cross-section, arranged so that if you’re holding the slide rule for normal use they run vertically! How odd! The metal bars appear to be embedded in a vinyl (or something similar) extruded matrix. Both the stators and the slide are comprised of two layers of the material I just described sandwiching an inner layer of a transparent plastic with a yellowish tint. You can’t see it very well in that scan, but that transparent layer is a little wider than the other layers on the slide (forming runners) and a little narrower on the stators (forming a well for the runners to run in).
Does anyone have a clue who the maker is? What the alleged benefits of this construction technique were? Any references to information about it on the web (I googled, but found nothing)?
I’d appreciate comments on this post if you have information…
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