In honor of both science fiction from the pre-digital computer era, and the paper-and-cardboard school of RPGs, the author of the Atomic Rockets site has an entire section dedicated to Nomograms
Not unauthorized. The changes were submitted and approved by the upstream engineers. And still might possibly have not failed (in spite of the stupid design error), if the hardware had the expected safety margin. Not much the contractors could have done about either problem.
IIRC from an analysis I read of the skywalk failure -
The original design had one hanger piece from the ceiling going through the beams of both walkways, with a bold below each walkway as support. The design therefore had a 20-foot or so piece of steel rod threaded at both ends and at the center. The obvious question to the engineers then was - Doh! - how do you put a bolt on threads cut in the middle of a smooth rod? As most builders will tell you - “typical engineers!” (Same design on each side of the walkways, so two hangers)
Since this minor stupidity was caught when it was time to hang things, the fix was kludged - one hanger from the ceiling to the first walkway beam. The next hanger started from a hole drilled near that hangar and down to the second walkway. SO, you had the full weight of both walkways trying to tear the steel between the two holes on the middle walkway like perforated paper. Apparently, on of the holes was drilled on the point where two beams were welded to make one long one.
Slide rules and calculations had little to do with it. The weakness between two holes was a second-order issue - with plain, undisturbed steel each hole was capable of holding the weight. Drill a hole nearby - no. Have a full load of partying patrons dancing too… no. Expect the same strength from a weld seam - not always.
I’d never paid much attention to the brands before, but it looks like my best slide rule is a Sterling Precision instrument. I also have a couple of Concise circular ones, a matched pair from a company that appeared to change its name from Lawrence Engineering Service to Engineering Instruments, Inc. (or vice-versa), a couple of pocket-sized from Industrial Gauges Corporation, and a behemoth called a Kane Dead Reckoning Computer, which includes a circular slide rule plus a bunch of other rules, charts, and nomograms whose use is a mystery to me. I also have a few other assorted slide charts, mostly pertaining to ham electronics.
K+E (Keuffel and Esser) is pretty much considered the gold standard of slipsticks.
I have a complete set of Log-Log Duplex Decitrigs that I.prize. Even use occasionally…
This ↑ ↑ ↑ This…
I still have & carry my first & only E6B in my flight case. It never runs out of power. 
I also have a larger round one that we used to find indicated actual height above ground from our indicated altitude when doing aerial mapping.
First electronic calculator I learned/used was an HP-43. What I used for several years. To this day I dislike the ones that have an ‘=’ sign. I have to stop and think about how to use it to get what I want. :rolleyes:
Sounds like a Otis King Slide Rule
Far be it from me to point out numbers to MIT folk, but the second line still doesn’t scan.
Nomograms are wonderful.
I remember when I used to read for a books-on-tape organization for the blind I was doing a textbook with a couple of them I had to verbalize.
When using calipers, I will always take a straight Vernier scale model over one of those silly dial calipers, or a digital one that might need the batteries replaced. Mostly because calipers are not for the ultra-ultra precision work (like you use micrometers for), and the Vernier scale is just so damn elegant.
For those reading this thread who aren’t familiar with what a Vernier scale is, it’s a rather clever way of increasing the accuracy to which a scale can be read by comparing two offset scales: Vernier scale - Wikipedia
Sometimes to an extreme degree: I’ve seen, for instance, a set of calipers capable of measuring to within 1/50 of a millimeter. This, on a device with only one moving part.
Sometimes dubbed a “math grenade.” I really, really want one. But in good condition they’re in the $1-2k range.
Years ago, I bought a bamboo Pickett like my dad once had, to put next to my computer as a display of anachronism. Not a high-end slide rule, but serviceable and easy to understand.
In my uncle’s massive pile of stuff that took us 8 months to clean out, I found a metal Pickett in a hard leather case that nine scales on one side and ten on the other, a few of which elude me. Unlike the bamboo model, there is no A/B, just a square root scale that works the opposite way (double-sided for even/odd orders of magnitude) and a hand dual π scale (C or D times π).
Kind of bothers me, though: how do you get a number accurately from one scale to another? The whole point of a slide rule is to do all the sequential calculations you can on it before you write a number down, to maintain the analog accuracy.
The Curta on YouTube:
http://www.youtube.com/playlist?list=PLXujGsmx0YjdCmuv1uLOZaZAHXDEhnzbU
There should be a sliding reticle with a hairline on it (though this often gets lost on old slide rules). You slide the hair over the number on one scale, and read it on the other scale.
RPI, freshman year 1967. Memories at the “Tute” bookstore. No calculators, too expensive, advantage to the wealthy. A nice new K&E WITH the leather case AND belt loop. I can’t remember even the nerds (of which there were many) actually carrying the slide rule on their belt.
Huh. I first heard about it as a cheer for Cal Tech.
Secant, cosine, tangent, sine;
Logarithm, logarithm, hyperbolic sine;
3.14159;
Slipstick, slide rule, Tech! Tech! Tech!
I never learned how to use one, and these days, my sole question about slide rules is: In what way did J. K. Rowling think a slide rule would assist Barty Crouch in achieving greater precision in trimming his mustache?
Probably some method only Han Solo would understand…
Yes, I am quite familiar with that thing (never heard “reticle”, we always just called it the hairline).
I was just thinking, the advantage to the slide rule was that you could capture numbers on the scale and retain the values in their analogue form through several steps, not losing accuracy until you had to write them down. Then I tried to get the fifth root of 7644 and realized that getting the mantissa onto the C scale to do the division was kind of an exercise in eyeballing the fraction, and then you have to eyeball the resulting fraction (being aware of where the decimal point will be) onto the log scale to get the result. Which, after several mistakes, did turn out pretty close.
With the big, double-hairline Pickett slide rule, there are lots of different scales, and sometimes the numbers need to move from one to another in order to do the next operation: every time that happens, the ultimate result will lose some accuracy.