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rettarchimedes
Some of the WWII K&E slipsticks were made with ivory on teak, and a very few ...
LCC23
K&E were plastic. Only Frederick Post (made by Hemmi in Japan) were plastic on ...
Slideshow: Slide rules and charts - a personal collection
Mort Hans
9/21/2012 2:01 PM EDT
Introduction (by Steve Taranovich, EDN senior technical editor)
The slide rule
The slide rule, sometimes called a slipstick, was a type of mechanical analog computer. It was and still is, used primarily for multiplication and division, and also for functions such as roots, logarithms and trigonometry. They come in a diverse range of styles and generally appear in a linear or circular form with a standardized set of markings (scales) essential to performing mathematical computations. Slide rules manufactured for specialized fields such as aviation or commerce typically feature additional scales that aid in calculations common to that field.
William Oughtred and others developed the slide rule in the 17th century based on the emerging work on logarithms by John Napier.
Slide rules were key to engineers in the 1950s and 1960s even though digital computing devices were being slowly introduced, but engineering students like myself from 1968-1972 could not afford the electronic versions.
Somewhere around 1974 the electronic scientific calculator took over the market and made slide rules virtually obsolete for the most part except for some "die-hard" traditionalists engineers who kept the slide rule in its case hanging from their belt.
The slide chart
A slide chart is a hand-held device, usually of paper, cardboard, or plastic, for conducting simple calculations or looking up information.
A circular slide chart is sometimes referred to as a wheel chart or Volvelle (Courtesy of Wikipedia: Led Zeppelin used a Volvelle on their "Led Zeppelin III" album. The cover and interior gatefold art consisted of a surreal collection of seemingly random images on a white background, many of them connected thematically with flight or aviation (as in "Zeppelin"). Behind the front cover was a rotatable laminated card disc, or volvelles, covered with more images, including photos of the band members, which showed through holes in the cover. Moving an image into place behind one hole would usually bring one or two others into place behind other holes.)
Slide charts are common collectables among technical people. Here is Mort Hans' presentation:





DaveR1234
9/25/2012 6:52 AM EDT
Great collection Mort. Thanks for the memories.
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Jestferfun
9/25/2012 1:00 PM EDT
You're welcome. Thank Steve for suggesting it.
Mort
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Auditron
9/28/2012 3:27 AM EDT
Auditron
Mort, I thoroughly enjoyed going through the years with your wonderful collection.
My dad, an architect, had a 5 or 6 inch K&E and at Cal Poly back in 1956, I purchased a full-sized Post Versalog slide rule (bamboo) which is still with me today. No, it is not for sale! And, no, I don't use it any more.
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Deodatta Shenai
9/25/2012 2:20 PM EDT
Awesome slideshow on slide rules. It's a great experience going down the memory lane. Thank you Mort Hans.
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shikantaza
9/25/2012 2:33 PM EDT
I LOVE that Battenburg Course Calculator. It isn't a mere slide rule, it's more like a danged ASTROLABE... more scientifical, but an astrolabe nonetheless
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Gerald.Hammond
9/25/2012 2:39 PM EDT
I was a college freshman in the fall of '72. One of my profs owned the first HP-35 on campus, and I owned the 2nd one. I worked overtime all winter break to scape up the cash: $916.80, including tax.
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dbhindin
9/25/2012 9:38 PM EDT
My memory and Wikipedia confirm that the HP-35 came out at $395.00 in 1972. I believe that the price point was carefully chosen. I was living in Hudson, NH when I bought mine. My memory is that the source was located in exotic Cupertino, CA, right around the corner from my present address in Sunnyvale.
http://en.wikipedia.org/wiki/HP-35
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dbhindin
9/25/2012 9:48 PM EDT
See also:
http://www.hpl.hp.com/hpjournal/pdfs/IssuePDFs/1972-06.pdf
confirming the price on page 13
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dbhindin
9/25/2012 9:58 PM EDT
and
http://www.codex99.com/design/126.html
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Curie_US
9/26/2012 12:06 PM EDT
You're correct about one thing, the date. I remember very well that time. Our company had just moved into a new, 40,000 sqft bldg. in August. A group of us younger engineers were discussing the merits of the H-P35 w/ its RPN entry method vs. the TI SR50 "Scientific Calculator". As we were into this discussion, a senior engineer interrupted our debate, with the profound announcement, "IF you fellows wait for the perfect product, you'll NEVER buy any!" Hearing this statement caused ALL of us to take pause, since we were all product design engineers embarked on a profession of advancing the state of the art in radio communications equipment. And, so with those words, he disappeared into the shadows of the engineering lab. As it turned out, I bought the SR50, and one of my colleagues purchased the H-P35! Ironically, BOTH gave the same results when we multiplied 4 by 3, so we were both very satisfied w/ our selections. But, I can assure you that in those days, the SR50 was nowhere near the price range discussed here ... more like $159., which was quite a bit in 1972/3
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The MicroMan
9/26/2012 9:25 PM EDT
Yeah, the HP-35 (and -45) started the calculator game. I think TI's SR-50 opened the door with a $159 or 149 price, but indeed there was a beauty to the reverse Polish notation (is that PC today?). Then the HP-21 (and programmable -25) started the smaller but better upgrade treadmill - and the one I bought. There was some secret 3- or 4-key combination you could hit on the HP's and fire off a free-running clock on the display (not time of day or even seconds counter). A lot of dispute early on about using calculators during tests or "make them show the long-hand - any idiot can push buttons and get pre-programmed answers." So now we have a lot of idiots! But things get done quicker.
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RegularJoe70
11/2/2012 10:26 AM EDT
I'm a big fan of slipsticks. I started using them as a young helicopter crew member when I used a whiz-wheel (E6B calculator) to figure fuel burn rates and time to burnout. No batteries to run out. No EMI hazards. Durable enough to get thrown in a helmet bag and beat around with the rest of the kit in there.
My dad bought a HP-35 when they came out in '72 (I was in diapers at the time) for something like $400. He said he worked on convincing Mom for a while to get it. I used a TI-85 and HP-48GX in school and much prefer the '48 with RPN. I'd rather do arithmetic longhand when it comes to using an electronic calculator without it! A couple of years ago, Dad got me a 35th Anniversary HP-35s for my birthday and it's my daily driver now. The '48 still works but it's at home with my collection of various slipsticks, wheels, and other HP calculators.
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ronflyer
9/25/2012 2:41 PM EDT
The big slipstick when I was in college 1952-56 was the Keufel and Esser log log decitrig. You should look for one of these to round out the collection.
Ron
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Jestferfun
9/26/2012 7:53 PM EDT
I agree and I do have one. It was a required purchase in my Freshman year and my warhorse until my first HP.
Mort
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RichDesigns
9/25/2012 2:48 PM EDT
To all the whipper-snappers when their fancy smartphone & calculator batteries run out or they lose their internet connection - these devices keep working.
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Howman
9/25/2012 2:55 PM EDT
Woah! Is that an Otis King Patent Calculator in your pocket or do you need to see your doctor about that prescription?
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Jose S
9/25/2012 5:11 PM EDT
This is indeed an interesting article that I have enjoyed reading, thank you, I still have my Post slide rule (page 10/14) and a pocket one by K&E very similar to the one on page 11/14. Thanks again!
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mikecousins
9/25/2012 11:50 PM EDT
i think i still have a K and E and you are welcome to it
mat.dct@comcast.net
they can win you a lot of money in a head to head contest with an electroniccalculator (you have to set the game a certain way)
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DAL9000
9/25/2012 5:20 PM EDT
I went to Engineering School (Ohio Northern ) from 1973 to 1977 and mine was the LAST engineering class to learn how to use slide rules my Freshman year - in fact we had part of our engineering orientation class on the 'how to use' the slipstick. It was a POST VersaLog sliderule that we wore proudly in a brown leather case attached to our belts. (I still have it and it still works perfectly. ) Also, mine was the LAST Electrical Engineering class to learn tubes - after that it was all RTL, TTL and other electronics! What a paradigm shift!
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grayhair
9/25/2012 6:12 PM EDT
The most important one for EE's that you are missing is a Spirule for root locus calculations.
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Jestferfun
9/26/2012 12:21 PM EDT
Don't have one, but you're quite right.
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gorby
10/29/2012 3:39 PM EDT
I saved all my slide rules... Picket, Post, and 6" K&E which I use still today to compute mileage in my Mini. .. and yes, Walt Evans' Spirule... in my drawer, along w the Sure Reactance rule. Somehow I lost my radar range calculator. Great tools. enjoyed the presentation.
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daniel i
9/25/2012 6:32 PM EDT
We learned how to use the sliderule whilst at technical highschool. For us the 'bees-knees' was a Hemmi sliderule. They were a Japanese company. I wish I could find it again! :(
They were made predominantly from bamboo. Beautiful sliderules...
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Jestferfun
9/26/2012 7:46 PM EDT
Try eBay. Lots of slide rules for sale. You might find the Hemmi
of your youth. :).
Mort
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Johannes Hans
9/26/2012 2:14 AM EDT
About logaritmus: did you heart something about JURIJ VEGA?He was author logarithem tablet, great scientifist who calculate PI on 140 decimal numbers. Receiver war medail from Maria Theresia 1796.
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T.ORR
9/26/2012 2:45 AM EDT
I still have a Shure reactance slide rule. I swipped it in 1973, and I still use it today.
It is much more practical than my 'electrical' pocket calaulator.
***************MAYBE IT SHOULD BE REMANUFACTURED ******************
Regards,
Tim Orr
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T.ORR
9/26/2012 2:46 AM EDT
I meant calculator!
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viking81
9/26/2012 3:39 AM EDT
A nice collection- I still have my dad's well worn K&E (it's hard to read in some places). When I was a senior in HS, I was offered the teaching sliderule some department had used for years, but turned it down (it was something like 3'x8')- just not interesting at the time, now I would love to have it. I like the idea of not needing power to do calculations (similarly, I hate e-readers), even though my personal calculator is a solar powered TI model from the late 80's, and still going strong. I really hate today's throw-away society. Nuff said.
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The MicroMan
9/26/2012 9:11 PM EDT
Pure slide rules are great. They are the incarnation of logarithms which are beautiful in themselves (along with certain series formulae and special numbers). I've got a 5-digit-precision circular slide rule that my dad used. I've also got some other tools and books that we all grew up on on my web site www.strategysanity.com/leroy.html and www.strategysanity.com/hooters.html
And the batteries never run out and you can use them on the airplane or in the theatre.
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ShaneBK
9/27/2012 1:03 PM EDT
Slide rules, like abacus, are much quicker in experienced hands, as long as you don't need 4 digit accuracy. Also great for verifying that you haven't dropped or gained a decimal place.
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Bigbert65
9/27/2012 6:08 PM EDT
Great collection. The digital calculator that spelled doom for the average engineer's slide rule was the HP-35. Many companies arranged group buys and discounts for their engineers. I still have my first one (works, if I use external batteries in lieu of the rechargeable pack). In Engineering colleges, one of the first things an aspiring engineer did was to buy "His" sliderule. (I also still have my first one). The next thing he did was to await the itinerant engraver who would visit campuses and engrave your name (small fee!) on the top. Pocket sized ones were often used as promotional items by suppliers. I have one given to me by CELCO (Constantine Engineering Laboratories Company). Abacuses (Abacii?) are another story. My small collection starts with one used by my grandmother on arrival here from "the old country".
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JD110
9/27/2012 11:44 PM EDT
Really nice collection-thanks for showing! My first calculator was the four function TI 2500 Dataman that I bought in 1972 for $125 (that's $688.93 in today's dollars!!). After the intro of the HP35 I waited for the HP45 to come out and in 1973 paid $395 plus shipping. Our married student housing monthly rent at that time was $60. My wife thought I had lost my mind spending that much for a "stupid calculator thing"! Initially we weren't allowed to use calculators on any exams we were taking but I didn't tell the wife that. :-) I ended up working for HP so I have a pretty nice collection of electronic calculators and still have the TI. Still have my pocket and big slide rules too. You may remember that at HP we first had various non-electronic calculators. A couple I still have are the Pulsed RF Calculator and and the combo Mismatch Error Limits/Reflectometer Calculator. I believe I may have more than one of each and if you're interested (and if I can find them!) I'd be happy to donate them to your collection.
John
K4KQZ
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Naptown
9/28/2012 1:07 PM EDT
Anyone remember the Curta? My lab partner in college physics labs had one.
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EDNRichie_Rich
9/28/2012 1:36 PM EDT
As for the Battenberg Course Indicator, it wasn't the "Famous" Lord Mountbatten that invented it. It was his father, Prince Louis of Battenberg who inveted the "course indicator" in 1892.
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Jestferfun
9/28/2012 7:04 PM EDT
Quire right. Thanks for the correction.
Mort Hans
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Ron R
9/28/2012 4:14 PM EDT
Does anybody remember the spirule for doing pole zero plots. Those of us who studied classical controls from D'Azzo and Houpis know it well. Also, back in the 60's GE had printed a special version of 3 and 4 cycle semi-log paper and made a clear plastic bode plot ruler with slopes for various numbers of poles printed on it. It made doing bode plots quick and easy. By the way, the Curta mentioned earlier was advertized widely in Sports Car magazines and used for road rallying. Unfortunately, road rallying was killed off by the gas crisis in the 70's
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Clyde
10/15/2012 1:49 PM EDT
I still have my spirule with the cover and instructions.
While taking controls at University of Kentucky ~summer of '72, one of the students was an electronics tech at IBM and he had an HP35. Very frustrating to the rest of us, but the professor allowed it. As freshman in 1960 (I'm a slow learner) we had totake a required non-credit class in slide rule use in Memorial Hall. Failure to 'pass' the class meant no graduation. Pass meant you attended the lectures as there were no actual tests.
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gorby
10/29/2012 3:50 PM EDT
Ron: I still have my Spirule. .. and someplace, I have that set of plastic templates (dif Q's) which were shifted around to get the right corner freq. I forgot abt those.
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mech engineer
9/29/2012 6:24 PM EDT
I find the "Engineering Slide Chart" very helpful. I use the plastic version & the App.
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beckerp360
9/30/2012 11:22 AM EDT
In the 1960's as a chemistry student in NYC the K&E Log Log DeciTrig was the ne' plus ultra of slide rules in its green leatherete case ( about a foot long!) hanging from your belt...no pocket protector for this baby!...and made from Bamboo for stability too. Then the collapsed pocket version ( only 8"long and almost the same resolution ca,me out in a white ivory like plastic and real leather sheath...I still have it somewhere As sometimes pilot I still use my circular speed distance calculator...no batteries etc. and light and lots of other features (density altitude etc) .on the back Jeppesen still has them I think...
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LCC23
12/17/2012 12:22 PM EST
K&E were plastic. Only Frederick Post (made by Hemmi in Japan) were plastic on Bamboo. Pickett were aluminum.
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rettarchimedes
3/29/2013 10:40 PM EDT
Some of the WWII K&E slipsticks were made with ivory on teak, and a very few were made in sizes longer than 12". I had the use of an 18" unit for one summer in the early 60's and I was told that there were some 24" units made for Los Alamos. I could get an amazing degree of accuracy out of that unit. I understand that some Japanese round units were made in 12" diameters in metal, and I seriously wanted something like that. Lacking that, I took off after computers after seeing my first computer in around 1959, a 5 ton Burroughs analog using paper or metal tape for I/O. I became a Senior Systems Programmer and participated in various hardware and software projects to include an early laser disk drive that handled 4 GB per disk at 3 MB/s for both read and write in 1982.
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JHankwitz
10/1/2012 8:22 AM EDT
Does anyone have Mort Hans address? I would imagine there're many like me that have their old slip-sticks collecting dust. I'd rather send them to someone that would appreciate them than to put them in the trash.
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Tech Ed
10/1/2012 10:22 AM EDT
Tech Ed
My trusty K&E Log Log Decitrig, bought when I entered Brooklyn Tech HS in 1943, serves me now as a visual aid in my docent duties at the Cradle of Aviation Museum on Long Island, especially wowing the young visitors, most of whom have no idea what I'm showing them. I use it as a counterpoint to the computing devices and power available today, and obtain gasps when revealing that many of the computations performed in the early stages of the US Space Program into Project Apollo were done on slide rules like mine. Audiences also get a kick out of hearing that Godzilla-size slide rules hung above the blackboards in most of my high school and college math and physics classrooms.
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Musician
10/10/2012 9:42 AM EDT
Very nice and enjoyable display/presentation! I still have my old pocket-sized Post Versalog slide rule (sold the full size long ago). I also have a circular slide rule with a Smith Chart on the back (obtained as an advertisement from a vendor). I also still own a TI DataMath as well as a number of "antique" TI scientific calculators from the 1970s. To RonR: Road rallying has enjoyed a resurgence. GreatRace Ltd. staged the coast-to-coast Great American Race in the 1980s and '90s (and perhaps beyond). To NapTown: A colleague of mine purchased a Curta, I think in Switzerland, while we were working in Europe. We were all envious of it. Apparently, there are still a lot of them out there. Try Googling "Curta".
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CarvinTom
10/31/2012 11:53 AM EDT
Ahhhh, Slide rules...sigh...I am still fond of my (now) 45 year old K&E LogLogDeciTrig. I don't use it much any more I (I don't do much with phasers these days) but I DO use the little 6" plastic one that I keep in my car for calculating mileage every time I fill up.
At the risk of sounding like an old fart, I feel that if newbies spent some time getting to know the slide rule they would have a better perception of the importance of checking each step of a calculation to see if it "makes sense before moving on the the next step?
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