The slide rule

[mark_in_manc]

I grew up with Casio calculators, but I have a big transparent slide rule somewhere which I think was once used a teaching aid on an OHP. I like using them - it's good to get away from electronic computers once in a while.

[Andrewausfa]

These are some of mine I use occasionally (cough..)

If I have the photos in the right order.
Pic 1 from top to bottom Thornton AC Electrical Rule 1941 ish 2. AW Faber No 398 from 1933 3. Blundell 802 Log: Log Simplex
Pic 2. 1: British Thornton 221 Duplex, I think the most complicated UK made rule 2: US made Pickett N-500 ES Duplex circa 1962 3: German Aristo 915 'Elektro' Duplex
Pic 3 the big boys, Aristo 0968 Duplex (a thing of beauty) and the Faber-Castell 2/82

Andrew

PS One more for the Cube fan boys

[Andrew2]

My goodness, that Aristo is beautiful. Takes me back to my schooldays when some of the Upper Sixth boys had posh ones.
Slide rules always make me think of brightly-lit 60's drawing offices with men in white shirts and smart ties.

[Andrewausfa]

Hi Andrew,

I think it's possibly 60 years old or so. I was just on the cusp of affordable electronic calculators for school children but there were still some people in technical drawing classes and A level maths etc who used slide rules. Nothing like this Aristo though, far too expensive!

[Oldcodger]

Nuvistor's post ,#19 highlights the difference between the old school where we used logs & slide rules and the modern world where calculators are king. I was taught ( despite the method being used) to do a rough mental calculation on the result expected. These days, whatever the calculator gives out is correct, despite the fact that for accuracy all input has to be accurate. I remember a chat with a maths lecturer at college in the 90's, ( I was an extremely mature 40+ student) , where he set a group of teenagers a maths problem, and he first asked them to give up all calculators. He was amazed at how few could get even close to the correct answer. He repeated the experiment in our group where we had several mature students, and the older ones could get close approximations to the answer.
Bit OT,but interesting.

[Terry_VK5TM]

I never got on with slide rules or log books, in fact didn't cope well with any sort of maths.

Never understood why you had to find 'x' when there it was written on the blackboard for all to see

Re the slide rule for resistors in parallel etc, I have a vague memory of there being one given away with one of the electronics magazines, maybe late 60's early 70's?

Cardboard of course and possibly did capacitors on the other side.

[Damien VK3RX]

I have a Faber-Castell 2/82 too.

When I started work in an engineering office in 1971, the only digital calculators they had didn't have decimal points. At the time I thought they were better than the slide rule, but only just.

I remember our finance office had a large mechanical calculator (see them occasionally on ebay). We could use that if necessary, but we used to sneak in and input some complex calculation then disappear, leaving the thing clanking noisily away for minutes at a time until someone wondered what the heck it was doing and pulled the plug

[Radio Wrangler]

I have a British Thornton 221 Duplex from my A-level days.
Being a student at HP, I wound up with a brand new HP45 which I still have.
Since then I got two HP11Cs which are my daily users.
On both my Apple machines, I have the Nonpareil simulated HP15s with icons in the dock.

David

[fetteler]

Originally Posted by Davewantsone

When I took my HNC way back in 1971. We were allowed you to use calculators instead of Log tables or slide rules for the first time. I foolishly bought an expensive Sinclair scientific calculator thinking it would be easier....

Are you absolutely sure that you had a Sinclair scientific calculator in 1971?? This seems a few years too early to me.
I remember that the Cambridge (which pre-dated the scientific) came out in 1973 - I got the kit form version for my 18th birthday but had to wait for a month or two for delivery because they had just been introduced and as was usual with Sinclair in those days they couldn't keep up with the orders....

Cheers,
Steve.

[Diabolical Artificer]

This old NASA tech did a few video's on slide rules inc speciality slide rules - https://www.youtube.com/watch?v=_nKDm12LqLI

Andy.

[John M0GLN]

I've still got my Aristo Studio slide rule that I bought about 60 years ago, it's probably at least 40 years since I've used it.

John

[dsergeant]

I got my University degree with a slide rule, my Thornton P241 was working overtime. Still have it but it is now gathering dust. That was from 1968 when the only calculators were mechanical things that you turned with a handle. Got my first Texas scientific calculator around 1975 (sadly died many years ago). 1971 is much too early for any generally available ones, certainly no Sinclair (but I did have one of their micro FMs, horrible thing...).

Dave

[Ed_Dinning]

Hi, I had several slide rules from a 12" and 6" that I used throughout university (PIC and Faber Castell makes), to circular track calculator rules for flying ( but I still remember the values of Sines for quick mental calculation of wind vectors.
Most of these require that you have some idea of what the answers should be, as well as it's power of 10 !!
I also have a variety of slide rules from suppliers to assist in selecting resistors, steels, screw threads and solvents/ chemicals.

There are also Nomograms that work on a similar principal, but where lines are drawn across several scales on a sheet of graph paper

Ed

[mark_in_manc]

A little OT - but you all might be alarmed to learn that students on a Civ Eng foundation course (one year, pre-degree) at a lower-ranking UK University where I currently do some PT work, have to be taught how to use a... tape measure. Really

[Craig Sawyers]

I used a Thornton slide rule while at school, and the first two years at University in the early 70's. Although decent calculators were available (I had one even then) you could not use them in electronics exams until the third year. So in the first two years I used my slide rule.

I went through a period a few years ago of collecting slide rules. Although I was keen to get hold of the types that Einstein, von Braun and Korolev used, I was really interested in the last gasp rules that were introduced when the writing was on the wall after introduction of the calculator. These are massive affairs with a huge number of scales. The Faber Castell 2/83N in particular was a thing of beauty with 30 colour coded scales, see for example https://www.sliderulemuseum.com/isrm...91%202-83n.htm

The equivalent Aristo is the 0972 with 31 scales. Cryptic and beautiful, it does not have the superb colour coding of the 2/83N .

I have new old stock examples of both of these. And several drawers full of others, many NOS.

There were others that included an "Addiator" on the back. That was a mechanical 4 digit adding machine a few mm thick, operated with a stylus that came with the slide rule.

Faber even introduced a slide rule with a four function calculator on the back!

The slide rule was used to design things like the Sydney Harbour Bridge, the first rockets, and even the Saturn V. The Apollo astronauts all took slide rules with them on their missions (the Pickett N300-ES; I have a NOS one), because you can do calculations independent of anything in the space vehicle or asking mission control (who would have used - a slide rule)

And then Hewlett Packard introduced the first electronic calculator in 1972, and global slide rule manufacture disappeared completely within a year, or not much more.

Yeah, I know - pass the tablets and a glass of water....

Craig

[Dave Moll]

Originally Posted by Nuvistor

I was taught, rightly or wrong, that with the calculations I had to do was at least know what the ‘ ball park’ would be and if I expected say 0.7 and my answer was 768.9 to think very carefully about does it seem reasonable. Anyway do the sum again.

Yes, it is all too easy to put garbage in and get garbage out, so it's always good to have some idea whether the result is plausible, and to redo the calculation if in any doubt.

[Dave Moll]

Originally Posted by Andrewausfa

I was just on the cusp of affordable electronic calculators for school children...

They hadn't made it into my classes in the late 1960s. The school had though recently acquired calculators similar to the one below

[barrymagrec]

Is that a wind-up?

[jez_145]

I left school in 1977 and I think I was probably in one of the last generations to be taught how to use a slide rule. The Maths teacher used a roller blackboard (actually a green board) housed in a wooden frame which had two hooks screwed into the top rail. Every so often, he would produce a giant slide rule, probably 5 or 6 foot long, and suspend it from the hooks to teach us with. Funnily enough, when I visited the school, some 25 years later, the board and the hooks were still there - no giant slide rule though.

I have owned two slide rules in my time; a cheap 6 inch pocket one, purchased from Boots, and long since departed, and a much better British Thornton AA-010 "Comprehensive" model which I still have. I used the latter at school and when I first started work in a drawing office as an apprentice. I found it quite handy for scaling dimensions as I didn't have any scaling rulers at the time.

When I started college, calculators ruled the roost and I quickly purchased a Casio FX-29 which I thought was absolutely fantastic. My Father had purchased an early Kovac calculator, a couple of years before, and spent well over 100 pounds on it, just for a basic four function calculator. My Casio was much cheaper and scientific too!

These days, I mainly use a HP35s RPN calculator but still find a Casio FX-115 best for hexadecimal and binary calculations and conversions.

There are some truly amazing calculators available these days, covering just about every aspect you could wish for, and for very reasonable prices too. I much prefer a dedicated machine though, phone and PC apps just don't cut the mustard in my opinion.

Would I go back to using a slide rule ? - no way !

Jerry

[ex seismic]

Like a lot of others here I went through uni with a double sided British Thornton. I never did work out how to use the second side! We were also taught the principle of a "gross error check". And now, again like so many others, there is an HP calculator programme on my phone and my PC, and real one in the drawer that gets used all the time.
The BT slide rule is also in a drawer even now, but hasn't been used in decades. Now you've all started me off I'll have to go and find it.