Electronic Calculator for Old Timers 1

[havesealwilltravel]

I realize that this is not strictly "history" but the following is both brilliant and cute and will be nostalgic for many of us.

http://www.cee.hw.ac.uk/~greg/calculators/sliderule/javasliderule.html

 

[eureka]

I received by BS in Engineering in 1958. I remember very well walking around campus with a slide rule hanging on my belt. That was a time affectionately known as BC (Before Computers). At least before personal computers. There was an IBM 650 mainframe computer on campus. It contained 2,000 storage locations on a rotating drum and filled a room with several cabnets containing vacuum tubes. We thought it was great!

 

[PSE]

I actually still have one. Complete with box, holster and instructions (after all I have forgotten how to use it for much of anything). I would be curious to know of other types compared to the "standard" one illustrated in the link.

Regards

 

[unclesyd]

I have a K&E Log-Log-Duplex Decitrig, which along with the Post were top of the line in the US. I Also have a Wallace&Wallace (Relay) that combined the components of both the K&E and Post. All these rules have 20-23 scales and use the front and back. I never did learn to carry the decimal point as a few people could.
As I’ve mentioned in other posts that when you were in a meeting and a made a statement and all the slide rules popped out you knew you were in trouble. Where as now you have no idea what’s going with the laptops and handhelds.

At the Alabama Polytechnic Institute (Auburn University) they had a 10' long rule for instructional purposes. It was quite accurate.
An interesting point is that most slide rules are made of bamboo due to its’ very low moisture absorption. No swelling or shrinkage.

 

[SlideRuleEra]

unclesyd - You didn't mention Pickett slide rules which could match speed & accuracy of other brands calculation for calculation. Pickett's scale layout use was different from other brands, but considered superior by some (kind of like comparing HP & TI calculators or IBM & Apple computers, I suppose). Almost all Pickett models were made from aluminium alloy which, of course, was totally unaffected by weather. Picketts did require regular maintainance, (wash with soap and water and lubricate about once a month). I will conceed that K&E rules were considered superior, but Post...? Not the way I remember.
Nice talking about the "Old Days" & Best Wishes

 

[unclesyd]

Sorry about the Pickett.
The old slide rule had its' advantages as I jut help out a firm where someone calculated a special fastener to 4 places and transferred it to a print. Needles to say the part as draw was going to cost about 10 times the part they really needed.

 

[RobWard]

I'm too young to have ever used a slide rule...but the irony of the amount of computing power that goes into a "virtual slide rule" just knocks me out. (I love it actually!)
My (older) brother loved it too, until he found that he had forgotten how to use one and thus couldn't show me how the darn things work. Then he got angry and muttered something about computers dumbing everything down.
Still, it's not as ironic as "texting": a phone call you have to type. Now there's progress...

Now I'm off to search the web for a "virtual Babbage Difference Engine"!

"I love deadlines. I love the whooshing noise they make as they go past." Douglas Adams

 

[BJC]

I still have my slide rules, K&Es the "belt" and pocket models. I bought two of the simpler ones and gave them to the cad guys here at work. I told them we went to the moon with these and we haven't been back since we started using computers for everything.
When I surveyed for the Forest Service we used Curtas for field calculations. Amazing machines, If you have never seen or used one don't pass up the chance.

http://www.vcalc.net/cu.htm

 

[RDK]

I have an old cheap plastic slide rule from my high school days. Its only 6” long and was kind of handy to take along.

I tossed it in the glove compartment of my car once and pulled it out at a gas station to calculate fuel economy. The teen-aged attendant couldn’t believe that a stick could be used for calculating.

I keep my Geotec Versalog slide rule by my computer. It has a label on the case “For use in case of power failure”



Rick Kitson MBA P.Eng

Construction Project Management
From conception to completion

http://www.kitsonengineering.com

 

[EnglishMuffin]

This is a little late - I never noticed this forum before, but it's very entertaining.
There is one thing that I always used to find useful on slide rules, and that was it's capability to quickly determine which integer ratios would come closest to some required value - very useful when designing gearboxes, and not easily done with a simple electronic calculator,
I completely wore out my old Faber Castell log-log, and was just about to buy a new top of the line model, when I was informed that I was completely nuts to be considering such a thing and so I bought my first Texas Instruments calculator, and never used a slide rule again. In a way, I wish now that I had bought one last slide rule - the model I was thinking of was a classic, and sells for hundreds of dollars today. There was a Faber Castell slide rule you could get at that time (I think about 1975) which had an electronic calculator fixed to the back - a move of final desperation on that company's part, and one of the most ridiculous objects ever made, but I did give it passing consideration at the time.

 

[EnglishMuffin]

dannym: By the way, the slide rule shown on that link of yours is quite unlike any that I have ever used - all the standard ones that I came into contact with had an A & B scale, which gave you the squares of the numbers on the main C & D scales. But this one seems to have CF and DF scales where I am used to seeing the A & B scales, and they are set up to give you pi times the C & D scale values. Interesting, but of questionable utility, I would have thought. Usually, on the ones I used, pi was marked on the C & D scales, and worked out OK. Maybe there is some cunning advantage to this arrangement which I am not aware of.

 

[IRstuff]

The CF/DF scales just simply allow you to use the entire multiplication range without having to reset the scale. Multiplying pi by 5 vs multiplying by 2 requires reversing the C and D scales, while the DF scale gives you everthing in one fell swoop.

TTFN

 

[EnglishMuffin]

Nothing wrong with that, but the question is, which is more useful - CF & DF scales or A & B scales? Actually, to be honest, I rarely used the A & B scales. Maybe one like this would have been better. But what I always seemed to need were more log-log scales. Ah - those were the days !

 

[IRstuff]

Maybe you just need to get a bigger one.

My aluminum Pickett-Post was about 2.5"-3" tall and see to have had both sets of scales. I lost it a while ago, in one of innumerable moves, so my recollection is a bit hazy.

TTFN

 

[EnglishMuffin]

Some years ago, I saw a slide rule advertised in one of those Russian surplus catalogs that you get in the mail.

http://www.foximas.com/russian/the-sextant-handbook.htm

It was claimed to be similar to "Korolev's magic wand" slide rule which sold for $7000 - Korolev being the legendary chief designer of the Soviet space program. I sent for one of these, but it was rather disappointing. For one thing it was very small - about 8" long, and very poorly made. And it was clearly not a regular slide rule. I had a Russian friend translate the markings, and as far as I could judge, it appeared to be a special purpose rule used for air navigation calculations - with things like wind speed and direction etc. So I have concluded it was a con. Korolev's real "Magicians Wand" was apparently a fairly conventional German made Nestler,

http://www.nasm.edu/galleries/gal114/SpaceRace/sec300/sec321.htm

which appears very similar to my old Faber Castell "Engineer's Log-Log".
Curiously, it also appears very similar to Werner Von Braun's Nestler.

 

[Skogsgurra]

My half cents worth:

The CF/DF scales were a great innovation, but we "cable guys" wanted "2CF" instead i.e. two times PI to get radians/second directly from Hz. After some thought, we realised that PI and SQRT(10) are very close and that the latter fact made multiplication over the whole 1 - 10 range possible without having to move the slide all the way back when doing 3x4 etc. The extra "overranges" at both ends of the scales made up for the differences between PI and SQRT(10).

I still use my Faber-Castell sometimes. It is a great way of keeping your "sense of proportions" alive.

 

[EnglishMuffin]

Maybe the CF/DF scales were more prevalent in North America or among electrical engineers or something - I've never seen them before. At the time I used a slide rule, I was still living in the UK.

 

[IRstuff]

I've gotten so used to Mathcad handling the units that I would probably be useless without it ;-)

TTFN

 

[nicabod]

I'm not anxious to drag a fine name (Keuffel and Esser) into the mud, but the plastic slide rule I bought at the Princeton U. Store in 1954 had inaccurate graduations! Some that should have lined up precisely didn't, even to a naked eye. It was of the Log-Log Duplex Decitrig variety.

I also remember that dropping a Pickett & Eckel on its end was a bad idea. The Al alloy was somewhat malleable, and iirc I mushroomed the end of the slide once, although not too badly. As well, indeed, you did need to tend to its lubrication regularly. I suspect that modern synthetic greases might not need such frequent cleaning and replacement.

Having been in the Pacific Fleet, I once owned at least one Hemmi bamboo slide rule; they were quite the equal of any others in quality.

As to exotic scales, one that I once owned (Hemmi?)had a Gudermannian (G?) scale; have long since forgotten what it was for. My father, an M.E. and scholar, was fascinated.

Indeed, I did use a slide rule to search for fractional equivalents with few digits, but only for fun. Reminds me that everybody should know about 355/113, a remarkably-good approximation to [pi]. Write down 11 33 55, and regroup. You can take it from there. No other rational approximation with fewer than six digits in the numerator is as good. The next better one is 104348/33215, very likely.

 

[notnats]

At UNSW in the sixties engineers had to do an accounting subject for one or two semesters.

At the first lecture we had to work out the simple interest on a loan, or some similar calculation. All the slide rules were whipped out and the answer was quickly calculated to 3 significant figures.

None of us could believe it when the lecturer told us we were all wrong. The bloody bean counters demanded a manual calculation correct to the last cent!!!!

Another story:

The author Neville Shute had a day job as an aeronautical engineer and if I remember rightly worked at Vickers with Barnes Wallace on the design of the R100 airship (the one that didn't crash and made a successful transatlantic crossing..my mum's cousin remembers seeing it over Toronto) and later had his own aircraft company.

In his autobiography, appropriately titled "Slide Rule" he describes the calculating office where every single calculation was done 3 times by a team of 3 engineers using 6ft long slide rules.

Happy days...

Jeff