Never was an engineer, but I do like the old stuff. (That's why I'm on the board with you guys).I'm a bit late to this, but I think that has to be a steel copy of the original engineers "slide rule". It was prolly made before logarithmic and trigonomic scaling was developed.
Sorry guys, I just couldn't help myself. Just kidding.
But seriously, when I took engineering, they didn't have scientific calculators so we all had slide rules. I still have mine some odd 55 years later.
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I picked up a second hand Pickett "Super-Computer" slide rule including the "Bat Case" a few years ago. Came out of Bristol Aerospace in Winnipeg. Apparently all the cool kids wore it on their belt so they would be able to calculate a log anywhere in the building. I can just about see two of them eyeing each other up from the far ends of a hallway and preparing to see who had the fastest draw.