I have a Keuffel & Esser 4012 Thacher Cylindrical Slide Rule that I found in the garbage at a university I used to work for.
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.
HN just wrecked all my morning productivity with particle spaces, and now my afternoon productivity is wrecked with dated computing devices. I will never get anything done.
”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 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
I thought about buying a slide rule just for fun to learn how they work. I couldn't find any regular sized traditional slide rules on Amazon. Does anyone sell them for a reasonable price?
They have not made slide rules in decades, so most of them are collectors items.
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.
If you 3D print your slide rule and write a blog post about it, it may be a good post for HN that can destroy the productivity of many people instead of just one :) .
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?
breitling's version does seem to have c and d scales, but it seems not to have a cursor, so it looks like it can't handle the very simple example i described in https://news.ycombinator.com/item?id=40324625 without a lot of extra mental work. and how would you do a square root on it?
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
i do not recommend settling for an e6b 'flight computer' or a slide-rule wristwatch; they are not at all equivalent to a standard slide rule. see https://news.ycombinator.com/item?id=40324625 for details on why those are bad
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
Most pilot's shops still will sell you an E6-B flight computer, which is essentially a circular slide rule on one side, and a wind drift correction table on the other side. Mr. Spock approves of the use of the E6-B for galactic navigation.
looking at https://en.wikipedia.org/wiki/E6B it looks like it would be very difficult to calculate, say, 124 × 53 × √14500 ÷ 0.77 on an e6b; it seems to only have two general-purpose scales and no cursor
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
Just to give you a hint about how they work, slide rules are based on the geometric mean rather than the arithmetic one: halfway between A and B on a normal ruler you will find ½(A + B), on a logarithmic scale you will find √(A × B).
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.
I have four side rulers, all of them I bought at antique stores. One of them, the Pickett N600, was used by the Apollo astronauts (it's small---6in (15cm) long, made from aluminum, and very nice). I think I paid about $10-15 for each of them.
i'm guessing you mean slide rules, and that the apollo astronauts used a slide rule of the same model as yours, not the one you bought at the antique store
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
I have major Ville Noko's sliderule from Winter War. Because he was architect and in artillery, this slide served dual functions. He calculated projectile trajectories and fortification parameters.
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.