10″ slide rules

10” slide rules
Hemmi, made in Japan, c.1954
Aristo, made in Japan, c. 1960
Royal, made in Japan, c.1960

The first slide rulers were developed in the C17th, for mathematical calculations. They were used consistently from this date until 1974, when they were replaced by the scientific calculator. The middle section moves between scales on top and bottom of the scales, and then an independent clear plastic slider is moved to allow the calculation to be read.

These 10” slide rulers [250mm] were made for the office; they are larger and allow more complex calculations that the smaller 5” portable scale rules […yes..they will appear in a previous post…I can’t help it…I love them!]

The Hemmi slide [topmost in the image] has a bamboo structure, with a plastic laminate covering; whilst the later slide rules are all solid plastic. All slide rules come in their own boxes [some with original operating instructions] and some have their original owners names incised on the box.

For sale: $AUD85

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2 thoughts on “10″ slide rules

  1. I still learned using slide rulers in school. We used one called “Aristo Scholar”. I think I still have it. I have another one, inherited from my father (who was a material science teacher) and my mother has one from her father, who was an engineer. Again, something was lost with the introduction of the electronic calculator (I still remember early pocket calculators, I wrote my first program, to calculate prime numbers, for a Texas Instruments programmabel calculator (I still have that one too, it is still working, and I think I still have the program code as well). That too is now obsoltete technology.
    I thin Aristo was actually a German brand (from a company in Hamburg).

    • Nannus- so interesting- the whole family used slide rules- and you then became a programmer; not un-expected! – i expect the Aristo was German technology, made in Japan. It is indicated on the instrument, as was so much at this time.

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