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Need help! I can’t find the Equal Sign.Rule #1, Slide rules need no batteries!
My first really good calculator was an HP35. Reverse polish is better in my opinion..........I miss it still.
Back in the eighties, I designed a circular slide rule the would calculate the length of bar stock required to make a shoe for a horse, based on two measurements of the horse's hoof. My ex, who was a farrier, made and sold quite a few of these to other farriers.Took course in engineering curriculum - nomography - we learned how to construct the "on paper" calculators that you laid a ruler across and connected the quantities you had making the ruler cross another line with the quantity(ies) you wished. Miles per gallon calculators are an easy example. Design of pressure vessels is a complicated one. Any equation can be represented with such a chart. It was a very informative course taught by an excellent professor and it explained a whole lot about how the world works and how we approximate it to our best benefit. Now we use spreadsheets and apps to generate these types of short cuts.
I used five place log tables a lot on college when we needed more precision than the slide rule would provide. One can appreciate the seven place tables when you realize that every additional place multiplies the number of pages of tables by ten. My five place tables in the CRC Math Handbook require 20 pages.A further more accurate slide rule was the drum slide rule used by a lot of Drawing offices. These had the logarithmic scales on the outside of a drum which could have a scale length of 500 " as opposed to the 10" normal straight linear type. Sure was a lot quicker (though not as accurate) as using log / anti-log tables ( 7 fig. tables in the D.O. !)
Happy days !
Yes I also have a few old slide rules including a circular trigonometry special, and a Sun Hemmi, a very nice engineering model from around 1970.You guys got me thinkin' (dangerous) about the distant past when slide rules ruled. I went digging around in my calculator drawer and found
a circular slide rule (from high school) my dad's very old wooden slide rule, three 6" mini slide rules??, my trusty log log decitrig that was a requirement to have hanging on your belt if you were a dedicted engineering student, and somewhere i have a cilendrical slide rule that if "unrolled"
woul be like 5 foot long (for greater accurcy). Then came my piece de resistance, my Curta mechanical hand cranked calculator which was a dream to use when I was on surveying crews. Then of course came the HP electronic hand held wonder that I have 4 different models of. jeese! Totally rediculous, except for the fact that I looked up Curta calculators online and the dang things are going for between 1000 to 2000 bucks! Thanks for making me dig into the collection!
one last thing I have to mention that I learned in high school:
As the animals left the ark, Noah told them to go forth and multiply. After some while, Noah happened upon two snakes sunning themselves. "Why aren't you multiplying?" Noah asked. The snakes replied, "We can't, we're adders."
So Noah and his sons went into the nearby forest and felled some trees. They made a platform of logs onto which they placed the snakes. You see, even adders can multiply on a log table.
Sorry
I have one just like that, but please tell, what is a Kennedy box?Found this round slide rule under the bottom drawer of a Kennedy box. I had a hard enough time learning the basics of a normal slide rule many years ago.
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As in used politicians.silly! A Kennedy Box is a box you keep Kennedys in.
Kennedy is a brand of tool boxes. Typically painted brown with many drawers to keep (and loose) tools in.
Considered as a must have by many.