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Off Topic - Slide Rules

HFS

HFS

Well Known Member
Anyone out there even remember how to use your slide rule? Post, Pickett, Decilon - remember ...

I think that last time I used mine was to mix paint.

And, the little steel ring on the back side of the case for carrying it on your belt. Only an engineer (read "geek") would remember (or admit) to ever doing that.

HFS

These are mine - both going on 55 + years old. Oh time, where have you gone?
 

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Stored in a box with the abacus and pocket protector? ;)

Alligation Medial for to achieve mixtures of specific concentrations? Used to use it all of the time, but don't remember the last time.
 
HFS said:
Anyone out there even remember how to use your slide rule? Post, Pickett, Decilon - remember ...

I think that last time I used mine was to mix paint.

And, the little steel ring on the back side of the case for carrying it on your belt. Only an engineer (read "geek") would remember (or admit) to ever doing that.

HFS

These are mine - both going on 55 + years old. Oh time, where have you gone?
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Memories indeed...I was a junior in college taking an advanced physics course, very proficient with a slide rule, when digital calculators hit the market (I resisted carrying the slide rule around in a holster on my belt .. even then I saw nerdiness as having limits). My dad's company had just switched over from the old Friden rotary calculators to Sharp digital calculators and he sent me a portable one, about the size of a paperback book. Just four functions but it did have memory function. My request to use that calculator instead of a slide rule during exams caused quite a stir in the Physics department but was ultimately granted. What a huge change that was in technical education.

I also recall a math assignment in high school where we had to create our own slide rule with markings out of cardboard. Something about "logarithms" if I recall correctly :). She then made us use the device on the test that week.


eta: no slide rules left at home, but I do have the old E6B I used as a student pilot more than 50 years ago.

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Got a box of them somewhere - My father was the Minnesota State Education Department Coordinator of Mathematics Education….he was constantly getting free slide rules, and I ended up with the drawer full. My favorites were alwasy the circular ones which is essentially the whiz-wheel portion of an E6-B. I still have a military circular pilot computer in the side pocket of the RV-8…just for nostalgia, and it doesn’t weigh much!
 
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I have two that are nearly the same as yours, HFS. The yellow one got me through USAF (I was in the final class that used them, the next class used calculators) and the white one was just something I picked up one day. When I went to college in '74 I immediately bought an HP-45, and still use HP calculators.

Remember RPN?

Dave
 
David Paule said:
I have two that are nearly the same as yours, HFS. The yellow one got me through USAF (I was in the final class that used them, the next class used calculators) and the white one was just something I picked up one day. When I went to college in '74 I immediately bought an HP-45, and still use HP calculators.

Remember RPN?

Dave
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I miss my RPN calculator...

Never used a slide rule, but my wife has her fathers slide rule. It was used to calculate balistics for the main gun on his tank in WWII.

-Dan
 
Still have mine. Was required for Physics and Chemistry in college. Used it to hand calculate and plot 3D molecular orbitals of oxygen atoms in Physical Chemistry. Took an entire weekend and about 30 pages.

Also good for hand calculating Clark Y airfoil coordinates at different cord lengths as the wing tapers..

Slide1 Medium.jpeg Clark-Y-1 Medium.jpeg
 
This group is getting really OLD!

I blanked off my 496 on a flight in the Bucker from Southern Cal to Washington St a few years ago and took out the Whiz wheel and chart ruler, tethered, just to see if I still had some pilotage skills. Uhhh, I did ok. The Bucker is relatively slow, so had lots of time to work it.
RV’s are not only loaded with all the flight management goodies, even if you didn’t have them, speed and range leave lots of options, most of the time.
Ah, the old HP. Took a while to reverse the logic in my brain after learning that thing.

Do they teach pilotage anymore?
 
I was a physics major in college, and had a cheap plastic slide rule. I started grad school in 1970-71 and, as a teaching assistant, was told to teach the freshmen how to use their slide rules. After that year I was drafted. In the fall of 1973 I was out of the army and back in grad school. The first exam I had to help proctor, I spotted students carrying bags full of extension cords, multiple outlets, etc. ‘Some new form of cheating?’ I asked myself. Nope. In the intervening two years, everyone had gotten an electronic calculator (battery life wasn’t great, they all wanted to keep them charged for the test.). The complete change over in just two years was amazing.
 
JonJay said:
This group is getting really OLD!m

Do they teach pilotage anymore?
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Here’s an interesting test. “Old guy” means someone who learned to fly before gps and moving maps. The others are “new guys”. If I put a pilot under the hood, turn off the gps/map, give him a few random vectors, then ask him ‘Where’s the airport?’ The ‘old guys’ say, “Oh, about 8 miles on a westerly heading.” (and they’re correct). The ‘new guys’ are totally lost, they haven’t got a clue.
 
I still have my bamboo slide rule. My Physics teacher in High School got us a great deal in a group buy and I took it with me to college. Calculators came out around my junior year, 1973. The HP35 was ~$600 and the TI SR10 was $150 but only had the 4 functions plus sq root and reciprocal . I bought the SR10 to use in Jet Propulsion class (I was in AAE.) The prof said we could use calculators but didn't want to see better than slide rule precision. He swore the tests could be done with a slide rule. I attribute my A to the calculator letting me take the long way around on problems and still leaving time to check the answers. Some day I'm going to mount my slide rule in a shadow box frame with the caption "In case of power failure, break glass."
 
I still have mine as well. Went to WVU from 1969 to 73. My son went there from 1998 to 2002. The first time he came home from college and was doing engineering homework on his PC, I got the old slipstick out. He asked what it was 😱. They weren’t even mentioned in passing!
I love the “in case of power failure, break glass” idea 😎
 
More trivia. In 1982, when I took the faa pvt written exam, the faa test writers were still using E6Bs. I know this because I took an electronic calculator to the exam and did the trig to 9 decimal place accuracy, for some navigation questions, and found that none of the offered answers was actually exactly correct. In every case there was one ‘best’ answer but it was surprising how far off it was.
 
Oh, I still have mine! A Post! Served me well in high school and early days of college! I need to put it on the Airplane shelf. After much grinding of teeth, I broke down and bought a Texas Instrument calculator that did All That and more! Blew me away! And ran on batteries! The slide rule took a sad back seat after that....... Using slide rules were how we were able to get to the Moon, by the way......!:D

My Cub came with one of the regular circular slide rules which I used on every cross-country flight. Didn't need all that other junk that came on the E6B :LOL: It's still in the Cub. Brings back memories just to look at it. Found a map (a folded paper device with landmarks, elevations, airports and other handy information) the other day that had the red line on it with tick marks on the various landmarks so I could keep track of my ground speed as well as stay on course. Red numbers were outbound; blue numbers were return flight. It was one of the sectionals that took me to OSH....Ah, THOSE were the days.....😊
 
dweyant said:
I miss my RPN calculator...

Never used a slide rule, but my wife has her fathers slide rule. It was used to calculate balistics for the main gun on his tank in WWII.

-Dan
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RPN - Reverse Polish notation ... Who knew?

At the time, my girlfriend's dad was a Vice President at SRI (Stanford Research Institute) in Palo Alto, and got some of the first HP (started in a garage by Bill Hewlett & Dave Packard) 35's prototypes for testing. He passed one along to me, which was quite a step up from the basic 4 function calculator from Sears I was using at the time ...

HFS
 
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HFS said:
RPN - Reverse Polish notation ... Who knew?

At the time, my girlfriend's dad was a Vice President at SRI (Stanford Research Institute) in Palo Alto, and got some of the first HP (started in a garage by Bill Hewlett & Dave Packard) 45's prototypes for testing. He passed one along to me, which was quite a step up from the basic 4 function calculator from Sears I was using at the time ...

HFS
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Once a year I receive a catalog of Math textbooks; that is surprising in itself, since I have been retired for 20 years. A few years ago, I was thumbing through the current catalog and notice they were selling slide rules. On closer inspection, I found they were being sold as novelties.
 
So it looks like many of us are of the age where we are doing the nostalgia tour of our lives.

The plastic Pickett slide rule on the left was the first one I had. I asked for it for Christmas when I was 15 years old, and taught myself how to use it with the included instruction booklet.

The Alvin Elite slide rule next to it got me through half of Aerospace Engineering school, until I bought the Texas Instruments SR-50 scientific calculator, shown on the right (yep, still have it!). “SR” stood for "Slide Rule". I could not afford the much more expensive ($395) Hewlett-Packard HP 35 as a college student. Even the SR-50 at roughly $170 was very expensive for the time.

I liberated the circular slide rule from NASA when I worked at the Manned Spacecraft Center (later renamed the Johnson Space Center) in Houston as a Co-Op student in the early 1970's during my undergraduate work. I've got a couple of other slide rules stashed away also.

In college during the transition from slide rules to scientific calculators, we would take both to exams as we didn't quite trust the reliability and short battery life of the then new calculators and felt we had to have a slide rule as a back up.

Slie Rules.jpg
 
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I carried this 4” slide rule in my pocket in my first engineering assignment. I left the full size slide rules in my office . . . until I got a calculator. 🤗
 

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HFS said:
Anyone out there even remember how to use your slide rule? Post, Pickett, Decilon - remember ...

I think that last time I used mine was to mix paint.

And, the little steel ring on the back side of the case for carrying it on your belt. Only an engineer (read "geek") would remember (or admit) to ever doing that.

HFS

These are mine - both going on 55 + years old. Oh time, where have you gone?
Click to expand...

I still have a couple, a mini one and a full size one

A few years ago, pre-pandemic when I was a road warrior visiting clients I frequently got asked capacity questions (that I thought were dumb). I re-taught myself how to use the slide rule, then kept the mini one in my laptop bag. When I got asked the dumb question I'd say "hang on a minute" and dig it out. Fiddle around with it for a few minutes, then give them an answer.

Most of the people around the table had no clue, some of the senior folks would exchange knowing grins.

Good for a laff.
 
I was awarded a very nice slide rule by the "Dallas Engineering Society" back in my high school days for top achiever in "Math Club".

Must have been 1960 or so.
 
HFS said:
Anyone out there even remember how to use your slide rule? Post, Pickett, Decilon - remember ...

I think that last time I used mine was to mix paint.

And, the little steel ring on the back side of the case for carrying it on your belt. Only an engineer (read "geek") would remember (or admit) to ever doing that.

HFS

These are mine - both going on 55 + years old. Oh time, where have you gone?
Click to expand...
I keep an old Pickett and the user manual on my computer desk just for fun. I was a kid when my dad bought his first Texas Instruments scientific calculator. He was really into that thing for awhile. He even bought a special calculator stand so his wrist wouldn’t get tired.
 
I've got a Pickett and two K&E slide rules. I used them when starting grad school in mid 70's. I graduated to an SR-10 but still went back to the slide rule for logs. I still have all of them here in a place of honor... or maybe a drawer somewhere.
 
pczar3 said:
I've got a Pickett and two K&E slide rules. I used them when starting grad school in mid 70's. I graduated to an SR-10 but still went back to the slide rule for logs. I still have all of them here in a place of honor... or maybe a drawer somewhere.
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You guys are alot smarter than me---I tried to figure out how to use it as a ruler. Just kidding
 
I started out with a simple Faber Castell in high school, then got a Versalog at BCIT just in time for electronic calculators to appear. Started with a TI-SR10, then a couple more up to a TI-59 with print cradle. Then I switched to HP and am still using my HP42S, my favorite, on a daily basis. I had always wanted a Pickett so I bought an N4ES, then a Faber Castell 2/83N Novo Duplex, and finally a K&E Decilon. Also bought a Pickett 600 6", yes, the one that went to the moon. Also ended up with some E6Bs, mostly Kane MK-6Bs. I discovered I had a collection, and so found space in my display cabinet in my living room. My engineering history told in slide rules and calculators
Terrys Slide Rule Collection.JPG
 
HFS said:
Anyone out there even remember how to use your slide rule? Post, Pickett, Decilon - remember ...

I think that last time I used mine was to mix paint.

And, the little steel ring on the back side of the case for carrying it on your belt. Only an engineer (read "geek") would remember (or admit) to ever doing that.

HFS

These are mine - both going on 55 + years old. Oh time, where have you gone?
Click to expand...
My Dad gave me my first "slip stick" when I was in high school for physics, calculus, and chemistry back in 1956. The wood was Teak and the face was ivory. Should have kept it
 
I'm too dumb for real slide rules, but I do have this prized whiz wheel, a WWII era D-4. A senior pilot gave it to me when I finished an L-4 restoration back in 1996. Flew it to Sun & Fun that spring...wet compass, sectional, pencil, wristwatch, and the D-4.

Now I don't even wear a wristwatch...

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terrye said:
I started out with a simple Faber Castell in high school, then got a Versalog at BCIT just in time for electronic calculators to appear. Started with a TI-SR10, then a couple more up to a TI-59 with print cradle. Then I switched to HP and am still using my HP42S, my favorite, on a daily basis. I had always wanted a Pickett so I bought an N4ES, then a Faber Castell 2/83N Novo Duplex, and finally a K&E Decilon. Also bought a Pickett 600 6", yes, the one that went to the moon. Also ended up with some E6Bs, mostly Kane MK-6Bs. I discovered I had a collection, and so found space in my display cabinet in my living room. My engineering history told in slide rules and calculators
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I think Terry wins on presentation points, if nothing else! 👏
 
Ahhhh…. Nostalgia. I remember going through Naval Nuclear Power School in 1973. One of my classmates brought in a brand new HP Electronic Slide Rule (cost $495 in 1973), and the instructors refused to allow him to use it. I had a K&E log log slide rule. We could get 6 digit accuracy with them. The raging endless discussion (like the primer one) was whether the aluminum Pickett was better than the bamboo K&E. We used graphite on both of them to make sure they were as smooth as possible. My preference was the K&E, but I had both. One my best memories was when my wife, daughter, and son-in-law went to see Apollo 13. When all of the engineers lept up and ran to the simulation room, I remarked that all of them grabbed their slide rules. My son-in-law turned to me and said “Dad, what’s a slide rule?” He was serious. So. I showed him one. And yes, I did have mine on my belt in high school .
 
vlittle said:
I still have an Otis King tubular slide rule, equivalent to a 66’ long linear slide rule in precision. I have a working HP-35 calculator on my desk. My 9 year old grandson that can do long division in his head, so I've got it all covered.

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THAT is kewl!

Mine:
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Toronto: n high school, 1970-ish, we were asked to write "SRA" on the top corner of exam papers if we used slip sticks for "Slide rule accuracy". Otherwise, we were using tables for complex calculations. There were no calculators.
 
LawrenceJames said:
Toronto: n high school, 1970-ish, we were asked to write "SRA" on the top corner of exam papers if we used slip sticks for "Slide rule accuracy". Otherwise, we were using tables for complex calculations. There were no calculators.
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Blount County, Alabama, 1970-ish, we were allowed to count our fingers. Toes were no longer in use, as by then most of the kids wore shoes to school ;)
 
Two great features of the slide rule:
- you simplified or reduced the expressions to minimize computations and you estimated the answer to get the decimal place. Exams were often written so that you could even do most of the math in your head.

These days you just punch in a bunch of numbers and read an answer off a screen, without checking or estimating.
 
Lots of great nostalgia stories here. I have my Grandfather's ivory and rosewood K&E slide rule. My grandfather was the first of his family to ever go to college, graduated University of Connecticut, B.S. M.E.. I forget the year, but something like 1920. Then my father used it. He was the first in his family to earn a graduate degree, M.S. Aero, Stanford, 1965. Then I used it.
I can multiply, divide, and find square roots. Those are the only functions I ever learned on it.

When I was a freshman at U.C.Davis, calculators had been out for awhile. The HP 35 we had at home was well used. My parents gave me an HP 81 as a high school graduation present. Boy was it sleek and slim compared to the HP 35. Endless discussions in classes at Davis, and that year, the consensus was that it was OK to use a calculator for homework, but they were not allowed for exams. Had to use a slide rule. By sophomore year that rule was gone.

I've always been a die-hard RPN user, I still have an HP-10C and and HP-11 at home, and an HP-11 app on my iPhone. I love it when you have all four stacks full, and your last four key strokes are all operators.

Oh, and I still program in FORTRAN 77 too. I learned some of the nice features of FORTRAN 90, but I've forgotten most of those.
 
vlittle said:
Two great features of the slide rule:
- you simplified or reduced the expressions to minimize computations and you estimated the answer to get the decimal place. Exams were often written so that you could even do most of the math in your head.

These days you just punch in a bunch of numbers and read an answer off a screen, without checking or estimating.
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As a consequence of the need to estimate I’ve noticed that if you give a person over about, say, age 70, a string of very large or vey small numbers to multiply or divide, they can quickly estimate the answer. Those under age 70, if asked to do the same, just give you a blank stare.
 
BobTurner said:
As a consequence of the need to estimate I’ve noticed that if you give a person over about, say, age 70, a string of very large or vey small numbers to multiply or divide, they can quickly estimate the answer. Those under age 70, if asked to do the same, just give you a blank stare.
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Well, I don't know about 70+. I'm only 67 ;)
 
scsmith said:
Well, I don't know about 70+. I'm only 67 ;)
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Well, I did say about. And if UC Davis had been slightly more enlightened, you would have joined the ‘unable to estimate’ group! BTW, my personal calculator is still an HP using RPN. And I remember when one of the main uses of a felt tip pen was to run a diagonal stripe down the edge of your punched card deck, just in case you dropped it! That, I don’t miss.
 
I still have my Post slide rule used in college. Also, a cheap plastic one I used in high school. I even have my tiny tie clip slide rule in the cavernous dresser drawer. I can still multiply and divide on them.
 
BobTurner said:
As a consequence of the need to estimate I’ve noticed that if you give a person over about, say, age 70, a string of very large or vey small numbers to multiply or divide, they can quickly estimate the answer. Those under age 70, if asked to do the same, just give you a blank stare.
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Speaking as a recent employer, I assure you basic math skills are at a very low level. About twenty years ago I added these challenging questions to my employment application:

1. What is 5% of $50?
2. If I drive 2000 miles per month, how far do I drive in a year?
3. If I use 1-1/2 cans of paint per day, how much paint do I use in 7 days?

Early on they asked for calculators. Or I would flip the application and find the back covered in calculations. Later applicants began asking if they could go to the car and retreive their cell phone...but not for the calculator function. Best I can tell, they expected to Google the answers. The scary part is now they can.
 
I absolutely agree with Dan. Ever notice the panic a cashier has when the total is $10.24 and you hand them a $20 and before you can hand them a quarter, they enter $20 into the register.

Back before electricity, several of my college classes did not allow any type of calculator (manual or electric) on tests and all questions required calculation work to be shown.
 
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