Slide Rules, Calculators and other fun stuff 1

[Skogsgurra]

Welcome to a new thread about old things.

The original Slide Rules Collecting thread is now 120+ posts and more than two years old. So it is time to close it and start a new one.

Collecting antique, old, and yesterday's calculating devices is a fascinating hobby. I have learnt about history, commerce, science history and lots of other things that I always find interesting. I have met nice people and - believe it or not - also held little speeches on the subject. Without being hit by rotten eggs and tomatoes!

Slide Rules are still my main interest. But there are also other interesting devices like mechanical calculators, old electronic calculators, drawing instruments, planimeters and what have you. It would be interseting to hear about those things as well.

Welcome!

Gunnar Englund

http://www.gke.org

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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

 

[IRstuff]

OK PC, you need to explain "dogs bo***ks."

"Behind"?

TTFN

FAQ731-376

 

[KENAT]

dogs bo***ks = cats miow

KENAT, probably the least qualified checker you'll ever meet...

 

[IRstuff]

Thanks... wasn't obvious to me whether it was a good or bad thing.

TTFN

FAQ731-376

 

[GregLocock]

depends if you're a dog

Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[PeterCharles]

"you need to explain "dogs bo***ks."

Take your pick!

http://www.peevish.co.uk/slang/d.htm

http://www.phrases.org.uk/meanings/dog's bollocks.html

http://www.oed.com/bbcwords/dog-bollocks-new.html

 

[bridgebuster]

flexible french curves

 

[C2it]

I still use an HP41-CV every day, originally purchased for a huge amount back in 1984. My old office memory ... that disgusting taste when licking an eraser to modify a drawing done in plastic lead. Yuk.

dogs bo***ks = muts nuts.

 

[geoffthehammer]

dog's bo.....ks = dog's danglies

 

[berkshire]

PeterCharles
Now you did it, your second link spelled it out.
Oops?
B.E.

 

[Skogsgurra]

A Polar Planimetre! I just got one. Fantastic device. But - how does it work? So simple and obviously doing it right (measuring areas of irregular surfaces). It is just sliding and rolling around and then comes up with the right area! Have to dig deeper here. Anyone done that?

Gunnar Englund

http://www.gke.org

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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

 

[IRstuff]

Not sure if this helps:

http://en.wikipedia.org/wiki/Planimeter

http://www.amherst.edu/~tleise/HomePage/planimeter.html

http://empublic.dcs.warwick.ac.uk/projects/planimeterCare2005/

TTFN

FAQ731-376

 

[Skogsgurra]

Yes! It helped. Thanks!

And I also found out that I had been hypercorrect in my spelling. It is NOT a "metre" it is a "meter" - because it measures.

But that sliding... No, I don't quite trust it. No more than I trust electronic devices.

Gunnar Englund

http://www.gke.org

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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

 

[unclesyd]

It is not mentioned often but the planimeter was used extensively in the chemical industry for totalizing flow from the circular charts prior to totalizing recorders. It was used extensively by the process accountants to allocate utility cost, process transfers, and verify yields/conversions.
One of my very first task was to learn to use the planimeter to verify any questionable results by the accounting department. I don't know why the girls were far better at it than me and I never got any numbers changed.

We made use of the pantograph big time in the manufacture of spinnerettes of any shape other than round . Our machine was developed in the early 60's prior to the advent on any NC controls. We used circular cams and used the pantograph to translate the circular motion to X-Y movement and at the same time reduce the output motion by a factor up to 50:1. By using this approach we could cut almost any figure one could draw.
These machines are still in use today.

 

[BJC]

Way back in mechanical lab we used planemeters to determine the BMEP of engines.
There was a device that connected to the cylinder of an engine that drew a chart of pressure vs positoin of the piston. Memory is hazy on this i can remember the device that measured the pressure. You had to wrap graph paper around it and it rotated.

 

[KENAT]

BJC, I seem to remember that Lab too, something about using it on Submarine Engines too.

KENAT, probably the least qualified checker you'll ever meet...

 

[Skogsgurra]

That one I remember! A so-called indicator diagram showing a closed curve with pressure vertically and piston position horisontally. But I have no idea why I remember it. Never got close to an ICE or steam engine in education or work.

Gunnar Englund

http://www.gke.org

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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

 

[PeterCharles]

Part of my college engineering training in the early/mid 1960's was a full steam engine test.
This involved firing up the gas fired boiler to produce the steam, monitoring the gas flow and steam produced, running the engine, doing a brake test and getting the indicator diagram on the steam cylinder which was then measured with a planimeter.
It was great fun, real practical test work. The flywheel had an internal recess into which you ran water to cool the brake surface, fine then rotating but as it came to a stop one lad was too close and got water all over his trousers and shoes!

I suppose now elf'n safety would mean you'd be watching a thirty year old film of it.

 

[unclesyd]

Fellows you are dating me.
I actually ran indicator diagrams on real live steam engines. These engines were the prime mover on IR 5CVE Hyper Compressors. We ran a diagram on one engine out of 5 a week. We would run one diagram and the mechanic would tune the valves and we would rerun the diagram. I mentioned before that we had very dedicated mechanic that keep these machines running so 99% of the time the diagrams looked like textbook examples. Even diagrams taken a year apart would fall right on the previous diagram.

We used a Elliot as shown on this site.

http://www.prestonservices.co.uk/instruments.htm

 

[BJC]

Preston didn't have an Orsat analyzer. Must deal in steam goodies only.

 

[unclesyd]

The Orsat analyzer was a ubiquitous laboratory instrument that for year was the only practical way to analyze for CO2, CO, and O2. Even though it saw a lot of use around and fired systems to help determine efficiency there were myriads of other uses both in the field an laboratory. If you took a hard look at the instrument it was lesson in chemistry in that it required the use of several basic principles, like absorption, adsorption, chemical reactions, and last but not least the gas laws.

My encounters with the Orsat started when I started school under the CO-OP plan. The lab where I worked accomplished around 30 Carbon Analysis a day using a modified Orsat to measure Carbon in CI, CS, and SS by means of combustion in an O2 atmosphere. This instrument was quite elaborate in that it had 3 different size volumetric chambers for measuring.
During my career in the chemical industry we used the Orsat to monitor the regeneration by steam/air oxidation of metallic catalyst, measuring O2 in the off gas of an air oxidation process, monitoring the inert gas systems, and keeping tabs on a bio-oxidation process and few more.
In my early days it seemed like every where I went I was lugging the Orsat and a volumetric gas flow meter around as I had become the expert due to my previous experience with same.