Do You Remember the Slide Rule?

It wasn’t all that long ago that engineers, astronauts, mathematicians, and students proudly carried the original pocket calculator. I had one and thought I was proficient at it. Sadly, I misplaced it years ago.

The slide rule was a simple device with one sliding part that could do complex mathematical calculations in moments. Multiplication, division, roots, logarithms, and even trigonometry could be performed with ease. But as technology marched forward with sophisticated computers and graphing pocket calculators, the lowly slide rule was forgotten.

Much of the engineering of the world we live in was designed with the use of slide rules, and yet they are almost forgotten today. Do you have a teen-aged child or grandchild? If so, ask him or her what a slide rule is. I suspect he or she won’t know.

William Oughtred

Wikipedia states that William Oughtred and others developed the slide rule in the 17th century, based on the emerging work on logarithms by John Napier. The online encyclopedia then goes on at length to describe the history, use of, and eventual obsolescence of the slide rule. You can read the article at http://en.wikipedia.org/wiki/Slide_rule.

Want to amaze your grandchildren? Buy a slide rule to show them. You can also keep it for nostalgia reasons. Slide rules can still be purchased from a number of vendors for about $20 or so if you start at http://goo.gl/bcgvT.

No batteries required.

37 Comments

Still have my Pickett log-log slide rule. My kids think I should be in the Smithsonian! Me not the slide rule!

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Nigel Huffingway Smythe February 13, 2019 at 4:06 pm

I am happy to have inherited my father’s well-worn Keuffel & Esser “log log decitrig” slide rule.

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    I also have MY dad’s K&E slide rule. He was so pleased when I used it in college in the late 60s – early 70s.

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    I had that same K&E slide rule myself when I went to Georgia Institute of Technology! Beautiful instrument. Still have it too. Replaced it with an HP35 calculator.

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You make it sound like they’re historical artefacts, Dick. Not only do I still have mine, and recall how to use them, I have a relatively rare circular one (basically and infinite slide rule). I demonstrated them to our daughters when they started learning about logarithms in order to demonstrate what they were actually doing 🙂

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    Not only do I have a circular slide rule, I continued to use it until I retired from teaching high school math. Using it to figure percentages was faster than a calculator.

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John Tracy Cunningham February 13, 2019 at 4:38 pm

I let my log-log go many years ago, but a few years back picked up an exact duplicate from eBay, with manual. It occupies an honored place in my study.

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Have 2. Fun to pull out of desk every so often. Like Steve, my kids also think I should be in the Smithsonian.

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Never had one even in early 1970s. Math teacher at the time won’t allow it. Has to learn very hard way.

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We had to buy a slide rule in junior high (for me late 50’s) and I have the 3 I’ve owned. The photo you include looks very much like my best slide rule, a Hughes-Owens Versatrig No. 1776 made by Sun Hemmi. In undergrad physics and chemistry courses slide rules had to be taken to exams, and in some cases a second mandatory tool was log tables. My first two slide rules are high quality, with bamboo cores covered with celluloid. Maybe you remember the ongoing chore of readjusting the screws on the end metal pieces as the humidity varied, because the bamboo swelled and contracted depending on weather conditions. You might find one day that the centre slide was seized, or alternatively if you gave it too hard a nudge the slide would go flying off to the side. You may also remember the irritation of lending someone your slide rule and their returning it with fingerprints all over the glass window.
The first electronic calculator I bought, around 1970 when I was in grad school, was a Texas Instruments SR-50A; note the “SR”. In that era you had to decide whether you were in the algebraic notation (TI) group or the reverse Polish (RPN), HP, bunch.

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Fish Farm math: length/weight of fish, feed chart, feed conversion ratio and the general math. But I have yet to learn how to stuff the same things into a spread sheet.

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In high school (late 1960s) I was probably in one of the last classes to learn how to use 5-place log tables with proportional parts! CRC Handbook of Chemistry and Physics, year-old version at discount 🙂

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Oh yes, I remember the slide rules I had from Junior High up through college. I even had a ‘circular’ slide rule! Sadly, that one was misplaced or lost in one of my many moves while serving in the Army. My favorite was a German slide rule that my uncle picked up in Germany during WW II that also disappeared during a PCS (permanent change of station) move.
I still have three I use from time to time to amuse my grandchildren as well as a really early calculator (an Abacus). Sadly, nowadays it is all handheld calculators, computers and excel spreadsheets. Oh well, time does march on!

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In the late 50’s, early 60’s I used a cylindrical slide rule – equivalent to a regular slide rule about 6 ft long. Fast and accurate we used to think. Also mechanical, calculating machines – remember those?

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I still have mine and my dad’s. I still use two small circular slide rules. On is in the car dividing miles by gallons (mpg) at each fill up – it stays pretty constant, and when the mpg starts to decline, it’s time for a tune up.
The other one is in my pocket when I travel overseas – set on the exchange rate – a quick glance then converts any foreign price to US. Quick and easy glance – no need to type numbers into a calculator each time.

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I was given a Castell slide-rule as a teenager and I still have it. For my UK proessional exams 1968-72 the only options were log tables or slide rule. Slide rule was quicker. I explained this and held up my slide rule during my retirement presentation – and only one other person knew what it was.

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Thanks for the chance to reminisce. Having moved quite often in my career, a few years ago I donated my drafting instruments and 3 slide rules to the local college. I knew my boys would not appreciate or understand them and this way the students will have a chance to see how we did things in the “old days”, that is if the Profs. know how to use them!

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I remember teaching new chemistry students as a TA in college about 1970 using a 6′ one that hung on the chalkboard.

I still have 3 generations of slide rules (mine, my father’s, and my grandfathers).

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I still have my two. A metal Pickett, model N1010T; original box with price tag – $13.00. Bought it while I was in high school. The second was from my college days, a Sun Hemmi No.260. I bought than one from a roommate who decided to switch majors. Paid him about $10. for it. Finally moved on to a TI calculator when I started grad school in the mid-1970’s. Much less expensive than the HP’s at the time.

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I have a slide rule, 8″ Floppy, Link Tape, HP Magnetic Card, and an IBM Punch Card in a shadow frame on our family room wall. We also have an additional slide rule in a drawer for the kids to try out.

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I have one from school, probably about 70s or so. Have been trying to sell it but have no idea the value of it.

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There is a great scene in the movie “Apollo 13” where the three astronauts pull out their slide rules to figure how much power and fuel they have left after the accident. I hope they still have them on the ISS and the shuttles in case the computers go down.

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My husband still has several. I remember in 1970, a friend had just returned from a sales trip to Japan, and we all gathered around him at a party to see the item he brought back with him. It was called a “pocket calculator” and it could add, subtract, multiply and divide! It cost $80, and one friend commented, “Some day every home will have one of these.” My husband said, “It will never replace a slide rule.” LOL

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I still have my slide rule from 1958 in 9th grade math class — it was a requirement. It proudly sits on a bookshelf in my office – in the original box !

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I never had one but my engineer father did and has passed it on to my engineer son-in-law. I remember my mom buying my dad’s first Texas Instrument calculator for the small sum of $300 back in the early 70’s. My how times have changed.

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I graduated from high school in 1951. Like David, I had to learn math the hard way, by learning the rules. No helpers were allowed. But later in my teaching career, like Kitty, I used the slide rule to figure percentages for grades. I retired before students were allowed to bring calculators to class.

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In Yogi’s words, this whole post seems like “DĂ©jĂ  vu” all over again.

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In high school I was crazy about a boy who was a smart science nerd waaay back in the 70’s, so I joined Slide Rule Club. As the only girl in the history of the Club, natch I was elected Secretary. (Good that SOME things have changed!) You never saw a more red faced, uncomfortable bunch of guys with a girl invading their midst. The teacher seemed to enjoy the whole thing. Always loved the smart guys! Lol

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Oh, yes, I remember them well. As an engineering student in the late 1950’s I carried my trusty K&E in a leather scabbard with a belt loop on campus just like a small sword.
I also have the circular one and a small one in a leather case that clips into your “nerd” pack. I am hoping that one of the grandchildren will take interest.

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A company I was with gave circular slide rules to our engineering customers. I still have -and use- one. Also have a straight one. Had two, but the cursor slider got broken. I even may still have one that is/was a tie clasp. That drew some comments!

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Dick, I recently sat and listened to a 101 year old WWII veteran explain a navigator’s circular slide rule to a 99 year old veteran. He showed us all how it worked. I was in awe! I wish I could post a photo of it here.

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In July 2018 I passed my father’s K&E slide rule in its original leather (crumbling) case from the early 1900’s and a second slide rule on to my son. We also spent an wonderful evening relearning how to use the Curta calculator I had given to his father years ago. Curta calculator is a ‘peppermill’ where you enter numbers on the side, crank a few times, turn the top ring, crank again etc. It is amazing. Anybody familiar with them?

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I remember them well. I still have the one I used in high school and college as well as a 5 ft by 8 inch teaching version a cousin of mine rescued from a dumpster outside a high school about 40 years ago. It is mounted on my living room wall and “people of a certain age” find it very entertaining when they come to visit.

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We still have my husband’s Keuffel slide rule. He used it in college at a top engineering school. Then, he used it at work building airplanes. We still have his leg holster. It has a tie the wearer tied just above the knee, gunslinger style. He’s told me in greeting a friend on campus they would draw their slide rulers like gun fighters.

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