Cylindrical Slide Rules
americanhistory.si.edu
americanhistory.si.edu
An old early 1900’s building was being cleaned out, and it was something that had probably sat on a shelf for years.
The crazy thing is why it was in the garbage in the first place…
The university had a strict inventory policy where anything with an inventory number had to be surplussed properly, whereas anything without one had to be thrown out as there was no way to prove it belonged to the university. And they apparently did not want to ever surplus anything (which lead to it being sold) if it was ultimately someone’s personal property.
I guess I’ll stick to my normal straight slide rules for now.
”While I was imprisoned inside Buchenwald I had, after a few days, told the [people] in the work production scheduling department of my ideas. The head of the department, Mr. Munich said, 'See, Herzstark, I understand you've been working on a new thing, a small calculating machine. Do you know, I can give you a tip. We will allow you to make and draw everything. If it is really worth something, then we will give it to the Führer as a present after we win the war. Then, surely, you will be made an Aryan.' For me, that was the first time I thought to myself, my God, if you do this, you can extend your life. And then and there I started to draw the CURTA, the way I had imagined it.”
It’s revealing that a Nazi camp manager in 1943 would dangle the carrot that someone could be “made Aryan.” Shows that the leaders didn’t actually believe the race bullshit.
I think that gives me some level of geek kudos
I learned to use a normal linear slide rule at school, but every time I look at this I have to read the manual to sort out how to use it. I'd like to fix it in my head so I could whip it out at work when calculations are needed. Just for geek points
Best would be to print one on legal sized paper, and cut it out, and learn the ropes.
Now, if you get more serious, you could glue said paper to a thin piece of plywood, and if you get even more serious, you could 3D print one.
I googled 3d printed slide rule, and now, after my morning productivity was ruined with particle systems, and my afternoon productivity was ruined with archaic calculating devices... my weekend is now ruined with trying to actually PRINT a slide rule.
When are the meetings for HN addicts???
It can be something simple like downloading the model and just printing it, or it can be your own design from scratch or something in between like a customization. Remember to take a few photos for the blog and write a short explanation, easy enough for people like me that don't use a 3D printer, and some technical details for people with their own 3D printer. Did I mention to include some photos?
* https://timeandtidewatches.com/how-to-use-a-slide-rule-bezel...
* https://www.ablogtowatch.com/how-to-use-a-watch-bezel-slide-...
* https://www.exquisitetimepieces.com/blog/slide-rule-watches-...
Breitling (for their Navitimer):
* https://www.youtube.com/watch?v=4PBRX8WCZR0
* https://www.youtube.com/playlist?list=PLH9N7loHYwCdCM3G68svj...
the marketing shill splog page in your third link describes several other slide rule watches, but unfortunately it's too busy with huckster patter to explain what their capabilities are; i suspect they suffer from the same weakness
full-sized 300-millimeter-long ones tend to run more like 50 to 100
if you're in the usa you can probably pick them up at garage sales and estate sales for a lot less than that
i wrote one in tcl/tk last millennium which you can run on any machine supporting tk, obviously including gnu/linux and i think still including android http://canonical.org/~kragen/slide-rule.tcl
printing one out on paper or transparency film, as foroldhack suggested, and gluing it to some pieces of wood can get you a much higher quality one than my tcl hack, probably equivalent to the quality of a hundred-dollar ebay find. for best quality, print out your scale on an inkjet printer, not a laser (lasers can have nonlinearity, especially in the horizontal dimension, though led-strip 'lasers' won't). i'm more confident in the horizontal dimension of the inkjet than its vertical dimension (the paper advance) but haven't been able to measure any nonlinearity in either
insist on at least a cursor and the a, b, c, d, ci, cf, and df scales. k and l are also big leaps in power. r1 and r2 are valid alternatives to a and b. the ll and trigonometric scales (s, t, st, etc.) are less often useful, i think (prosthaphaeresis has been obsolete since 01614), but still general purpose. and of course there are numerous slide rules with special-purpose scales for other special functions; https://www.sliderulemuseum.com/Aerospace/MartinSpaceRule_Ea... has scales to shortcut calculating things like the specific impulse needed for a rocket to escape a particular planet's gravity
https://www.nicolamarras.it/calcolatoria/regoli_aeronautici_...
https://mediafiles.aero.und.edu/aero.und.edu/aviation/traine...
on a standard linear slide rule, the most obvious way to do this calculation takes five moves:
- move the slide to align the left d scale index with 1.24 on the c scale;
- move the cursor to 5.3 on the d scale, thus putting it at the position of 6.57 on the c scale, which you know means 6.57 thousand;
- move the left index of the d and b scales to the cursor;
- move the cursor to 1.45 (not 14.5!) on the b scale, thus putting it at the position of 7.91 on the c scale, which you know means 7.91 hundred thousand;
- move the slide to align 7.7 on the d scale with the cursor;
- read the answer, 1.028, off the c scale at the left index of the d scale, which you know means 1.028 million. (the 6.57 was an approximation of 6.572 because on a normal-sized slide rule you can't read things off to four significant figures that far up the scale, but you can definitely tell 1.028 apart from 1.025 or 1.030, though possibly not 1.027 or 1.029)
i think you can do this same calculation in just three moves by using the ci and di scales (and maybe a instead of b), or using cf, df, and cif for some of the calculation, but i never learned how to use a slide rule properly because i was born after the hp-35; hopefully someone who was born before 01960 reads this thread and can explain a better way to do it
you can do this with just c, d, and l scales if you have to, but it takes some mental work (and extra moves) for the square root. at a given length, circular slide rules are better because they save you from having to choose between the left and right indices, and their maximum dimension is smaller, being almost τ times smaller than a linear slide rule of the same length — but they also tend to weigh more
looking at https://upload.wikimedia.org/wikipedia/commons/c/c4/StudentE..., the e6b seems to have c and d scales (this is an edit correcting my earlier version of comment, which claimed it didn't). they're the scales in this photo that say 'imp. gal.' at the top. but for taking a square root i think you're on your own, and it doesn't seem to have a cursor, which is a significant drawback. and i'm skeptical of the play in the grommet used as the pivot; it seems like that could really hurt your significant figures
so, probably do not buy an e6b in order to learn about slide rules; you will be almost as disappointed as if you bought it in order to learn about computers
Due to exponent rules this makes it possible to use two logarithmic scales to compute A × B / C in the following way:
1. Line up one scale’s A with the second scale’s C.
2. Look for the second scale’s B on the first scale.
When you're multiplying, C is usually 1 or 10 (this would usually be done with scales labeled C and D) and when you're dividing B is usually 1 or 10, but sometimes your problem works out that you can just do both at once.
the prices i see on ebay suggest you could sell most of them for significantly more than you paid; unless you have slide-rule-fancying heirs, try to do this before you die, because otherwise they're likely to end up in a dumpster
In junior high, I was an enthusiastic member of the slide rule club (late 50's).