Archive of Collections

Details and Image

TypeModel No.MakerCountryConstruction
DateScale LengthArea of Use
Precision Scale parts and partial slide rules
Precision Scale
25 cm

Notes: "Precision Scale was one of the companies, maybe the last one, that Arthur Eckel formed after leaving Pickett and Eckel. The most commonly seen product of Precision Scale is US Air Force aerial photography slide rules. The Precision Scale slide rules differ from the much more common Picketts by the shape of the end braces. Shown are two nearly complete slide rules (missing some screws), one of them a very fancy log log slide rule with hyperbolic scales and a double-length square root scale, and branded “Precision Scale. The other almost-complete slide rule is 8.75” long overall, with the closest thing to a fundamental scale on it being 6.5” long. This appears to be a loan calculator for a company called KAFCO. Interestingly it was made by Eckel Inst. Co. of Arcadia, California. Arcadia, California is where Lithocalculator and The Eckel Co. were both located, those being the two brand names seen on Eckel circular slide rules. Precision Scale was located in Phoenix, Arizona. Shown is a slide rule blank that has been drilled but not printed, and another that has been drilled and printed with the scales for an Air Force aerial photography slide rule, but never cut apart into separate stators and slide. This one is quite a bit wider than the usual Precision Scale aerial photography slide rule, with an additional “Ground Size (Meters)” scale on the top edge, plus larger fonts and wider scale spacing overall. In addition there are three slide rules without slides, two individual stators, one with two end braces and the other with just one, and a collection of end braces (Pickett-style: 12 left, 3 right, Precision Scale style: one left, 10 right with three having internally threaded rivets inserted), and a latch to go on the tongue of a leather case. There is also a 5” Sterling plastic slide rule. There are no cursors or cursor parts."

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