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Slide Rules. Collecting and discussing. 13

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Skogsgurra

Electrical
Mar 31, 2003
11,815
SE
Hello all,

You are invited to share views and thoughts about slide rules. I have been collecting these devices on a rather small scale and had fifteen of them when my collection took a quantum jump. I was visiting the local book store to buy a book on flowers (yes, flowers) when I happened to ask the store-keeper if he perhaps had any slide rules. He gave me a puzzled look and then said "Yes, I found a box with some forty old slide rules yesterday. I haven't decided what to do with them yet".

Need I say that I saved them from the scrapheap? I got a substantial addition to my collection at a price that we both were very pleased with. He because he got anything at all and I because I paid about a tenth of what I had expected to pay.

I have mostly European and Japanese slide rules. Faber-Castell, Aristo, Sun-Hemmi and some less known makes like Graphoplex (French), Diwa (Danish), Royal Slide Rule (British) and Eco Bra (can't make out from where it comes).

There is a certain standardisation among slide rules. There are the scale systems; Mannheim, Rietz, Darmstadt, Electro, Disponent and some other special systems. There is one that intrigues me. It is called Tachymeter and seems to have been used by surveyors. And there are probably many more that I haven't discovered yet.

The slide rules from the BHP era look very much the same except for the introduction of the Duplex slide rules in the late fifties/early sixties. That was also when some colour was added - except for the "reversed" scales (increasing from right to left instead of from left to right) which seems to have been coloured red for a very long time.

It was only AHP that design people started to make the slide rules more and more attractive. Mild colour coding, more scales and cursor lines, extra functions, friction areas to ease handling, table stands and more was added to keep a market that everyone probably already knew was lost. The last slide rules produced were sometimes monsters - or beauties - depending on your personal preferences. I, myself, think that the Faber-Castell 2/83 N (the N is important here) is a beauty. It is the longest 1 foot SR produced, I think. It has 30 scales and it even smells good!

Another favourite is the little FC 67/38b 400 grad Tachymeter. It is a favourite mostly because it is so enigmatic. What are sin.cos and cos2 scales used for? They are probably there for some very valid reason - as is the 1-cos2 scale. Anyone that has information about these scales?

Collecting slide rules appears to be the retired engineer's perfect hobby. We know a lot, but not all, about the objects. We can appreciate the good workmanship, the precision, the artistery and the ingenuity that went into their design and production. And we know how to use them!

There are a few other reasons that make them ideal collector's objects: They are no more produced. They are still available - although in limited quantity. They are not bulky - can be carried with you when meeting like-minded. There will probably never be a fake slide rule - it takes a very complex production facility to make slide rules and the last factory was closed in 1975.

It is a little like collecting Fabergé eggs - only so much cheaper and more interesting.

Comments and answers invited! Do you collect slide rules? Do you have specific knowledge about any special slide rule? What makes do you know about? How do you find them?

BHP = Before HP.

Gunnar Englund
 
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The small one is an "Aristro" Rietz (Nr.89). The bigger has been used for quite a while and its harder to see. Two words i can read on it though; "Küller" and "Impert". Feels good to know where i can get new ones if i break one. I have been looking around at the company for old sliderules but still havent found any... The search continues, somewhere at this old company (350 years this year) there must be a treasure chest full of them!
 
Giv me a ring when you find it, manga!

BTW, I visited a couple of slide rule designers yesterday.

Yes. It is true. They have designed lots of specialised slide rules for HVAC and similar applications - but also a circular slide rule that was produced in large numbers by the German company IWA.

I found one of those circular slide rules in a stationery shop this summer. All that was printed on it was System Wern IWA 1638 Made in W. Germany.

Some research led me to a German site where IWA was mentioned and from there I found a reference where i could read "von einem Schwedischen Ingenieur Wern konstruiert" (designed by a Swedish engineer named Wern).

I got this wild idea; is he still alive? After quite a lot of research, I found his niece in southern Sweden. "That must be uncle George" she said. If he is alive? "Yessir! He and his brother Carl live in Stockholm."

So I went there to have one of my life's better interviews. Two absolutely stunning 80+ year old gentlemen that had all the history and all documentation on their shelves. Even a specially designed machine for producing the masters!

I will write an article in the Journal of Oughtred Society about it. And guess what? I had a very nice addition to my collection when I left the brothers - Two MIB 1639, a set of unique HVAC slide rules from around 1970, marketing material, manuals and other documentation.

Gunnar Englund
 
Interesting article about Slide Rules!

The May 2006 issue of the Scientific American has a well-written article "When Slide Rules Ruled" by Cliff Stoll. It is a good introduction to slide rules and also about the historical development. The ending words (a slide rule talking to a PC) are worth pondering: "Watch out! You never know when you are paving the way for your own successor."

Gunnar Englund
 
skogsgurra - Thanks for posting about the Scientific American article. I went to the library and got it. Plans to build your own (paper) slide rule are included. In fact they are available (free) on the web at this link

...and I made one, and here it is
SCIAM-SlideRule.jpg


Accuracy is not too bad. Here it shows 12.2 x 17.8 (or wherever you want to put the decimal point) = 215 (versus a precise 217.16)
SCIAM-SlideRule-215.jpg


[idea]
 
Through the fall of 1999, I kept my 1972-era 10" Decilon, in its nerdy leather case, on a hook beside my PC. I stuck a dymo label on it that read, "YTK Compliant".

Meanwhile out IT people were driving everyone crazy making sure we were ready for the end-of-civilization-as we-know-it.

I still carry it in my briefcase for those times when the calulator or laptop batteries fail.

Interestingly, this slide rule cost me about about two days pay, at the time (just out of high school). Now, two days pay will buy one one my kids a PC.
 
Has anyone seen FEARNS rotary slide rules.
I got one sone years ago that calculates the volume of cylindrical vessel with flat ends, domed ends (concave or convex ON ITS SIDE like you would have with a storage tank.
You dial in the dimensions (Metric) the actual depth of liquid & it gives the answer in a whole range of umits from cobic metres & feet to barrells & gallons (both US & IMPERIAL)

on the otehr side....it does rectngular tanks
The company FEARNS was in Gateshead in the UK.

They also did calculator factorpacks with multipications factors that convert any unit to another - these were produced when electronic calculators were introduced.

Ive got one & its a trusted possesion. One guy I worked with programmed this data into a spreadsheet on a PSION pocket computer - which made a very sophisticated calculator...
My first real slide rule was a Faber Castell double sided one which was far better that using log tables !

Remember log tables.....this was all OK till I got into 7 figure logs.



Bruce L Farrar.
Works Engineering Manager
Marshalls Mono PLC.Brookfoot Works.
Halifax W.Yorks UK
 
Anyone remember the scene from the movie "Dr. Strangelove" where the named doctor gets out a circular sliderule to calculate the half life of cobalt 240G?
 
That is a good idea! I think that it is time to start a new thread where we list references to slide rules in movies, litterature and plays.


Gunnar Englund
 
From the script:

"Muffley:

How long would you have to stay down there?

Strangelove:

Well let's see now ah, searches within his lapel cobalt thorium G. notices circular slide rule in his gloved hand aa... nn... Radioactive halflife of uh,... hmm.. I would think that uh... possibly uh... one hundred years. On finishing his calculations, he pulls the slide rule roughly from his gloved hand, and returns it to within his jacket.

Muffley:

You mean, people could actually stay down there for a hundred years?

Strangelove:

It would not be difficult mein Fuhrer! Nuclear reactors could, heh... I'm sorry. Mr. President. "

Peter Sellers was a genius...

I wonder what "cobalt thorium G" is...
 
Hey,

I'm watching Apollo 13 on TV this evening (commercial right now) and they are right in the heat of the moment of trying to recover from the accident, and look at those boys in mission control zapping those slide rules.

That was 1970 and I was still toting my slide rule to classes at that time in my life.

What a reminder.

rmw

PS: sorry Skogs, I just scrolled up a couple of posts and noticed your note about slide rules in movies. Well, there they were. Sorry commercial is ending and I am on the edge of my seat. I hope these guys make it.
 
Hello!

There was some mentioning of circular slide rules in earlier postings. And now, there is a Wern 1638 (circular with unique properties) for sale on ebay. Please don't bid! I want it! ;-)

The reason that I want it is that I have researched the Wern calculating disks rather thoroughly. And I actually met the Wern brothers. They are still active (age 83 and 83+). I also wrote an article about the 1638 in the Journal of Oughtred Society and the issue containing that article appeared this week. I guess that is bad timing - price of the 1638 may increase a bit when people see how good it is...

Anyhow, I think that we should start a new thread where slide rules and other calculating intruments appear in papers, movies, poems(?) and novels.

Gunnar Englund
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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
 
What a treasure find!

A tachymeter for surveying os a mind of theodolite, and not similar to a slide rule.

A slide rule type tachymeter is something different. Some watches have them around the bezel. It is a kind of circular slide rule that relates time, distance travelled, and speed.
 
Way back I used a Curta when I was surveying for S. Bear ( aka Smokey the Bear or the USFS). It would do trig calculations out to 6 or more places.
I had a Wilde theodolite, a book of trig tables, a field book and the Curta. A few dozen revolutions and the answer appears ready to record in the book.
Now I believe the theodolites communicate with the engineering office and roads are designed before you ride the horse back to basecamp.
I may buy a couple on eBay just as an investment. Wonderful machines.
 
I used a slide rule in the army in the late sixties for doing calculations for the weight classifications of bridges. I was the ONLY one in a class of sixty young tank commanders who knew how to use a slide rule. The others were doing multiplication and division by hand on scraps of paper. Needless to say, I had them all beat in both speed and accuracy.

I also used an E6B circular aviation calculator extensively while flying. If you're not familiar with these, in addition to the normal time-speed-distance stuff, they have conversions for pressure altitude, true air speed, etc., plus a handy way of playing with the wind's effect on flight path.

I still have a Picket 10-10-ES in the desk that I take out on occasion to a: do a quick calculation and b: prove a a REAL dinosaur I am...

old field guy
 
Dinosaur here too!

I have a device called E6-B2 Computer. Same as yours? It is in aluminum and consists of a round part with two circular scales with three windows in it. It slides on a rectangular part with scales and formulae on it. Plus a very impressive set of lines and arcs. There is even a locking lever.

I have no idea how to use it - it is just a very impressive piece in my collection.

Have a look at the Wern 1638 at
It is a beauty - isn't it?



Gunnar Englund
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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
 
No, I don't collect slide rules, but I credit a slide rule with saving me from juvenile delinquency and who knows what thereafter.

I was fed up with the 4th grade arithmetic. Day after day, page after page of long divisions and 3 and 4 digit multiplications. Pure drudgery. As if solving more problems, after the principle had been learned, was of any value. Not that I couldn't solve them, but why? I did a couple days' worth, got them all right, I'm ready for something new. But not the school system, nooooo. I so despised those pages of drudgery at the time, that I wrote down random answers, rather than submit to the drudgery. And being a bad boy was fun and I started other bad behaviors.

My dad, seeing my marks go from A's to F's and getting a note from the teacher, asked me what was going on. I told him, he agreed that doing mountains of long division problems was stupid and said, "we'll fix that". He got out a slide rule and proceeded to show me how the log scales add up (cool concept) and how to multiply, divide, and do square roots.

Taking an expensive engineering slide rule to school wasn't necessary, so he drove me down to Cy's drug store and he bought me a small 5" or 6" cheap, plastic slide rule that was in amongst pens, pencils and rulers on the stationery shelf. It fit in my shirt pocket (probably the same model Rick Kitson RDK mentions above). I think it was $0.29 at the time (1960, and no sales tax in Erie county). I used that slide rule in class, day after day, effortlessly completing the problems in a matter of minutes, and then read a book for the remainder of the arithmetic session. I actually took that slide rule to Sundsvall in 1967 as an exchange student, and used it in Fröken Hunewall's chemistry class.

No, the 4th grade teacher never said anything. I suspect now that she didn't know how to use a slide rule and was afraid we 4th graders would find out, blowing her goddess authority cover. She left me alone.

Great things those slide rules.

Dan
 
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