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The Data Scaler Proportional Rule

March 3, 2020 / Nathan Zeldes / 0 Comments

The Gerber Variable Scale, described here, is a thing of beauty and elegance, admirable for its ingenuity and craftsmanship. It is also a “one of a kind” device, or so I thought until my unexpected sighting on eBay of the “Proportional Rule” made by the Data Scaler corporation of Westfield, Massachusetts.

The Datascaler Proportional Rule and the Gerber Variable Scale

This device is a clone — a direct knock-off — of Gerber’s elegant invention. Close inspection shows the small differences in design and manufacturing quality that usually accompany such cloning.

This article examines the details, and uncovers who made this device and under what circumstances.

Check it out!

Three Controllers – and their Grandpa!

December 31, 2019 / Nathan Zeldes / 0 Comments

A few years ago I sighted on eBay a set of three German circular slide rules of the Controller brand. There was a big one, 20 cm in diameter; a midsized one 11 cm across; and a small one at 7.5 cm. They all looked pretty much the same except for their sizes, and this reminded me of those three bears in the Goldilocks story — a thought that amused me enough to push me into buying them. So now I had a Father Controller, a Mother Controller, and a Baby Controller. Three Controller circular slide rules
Actually this type of slide rule is fairly common, and is often seen on eBay. But then, one day, I saw an auction for what can only be described as Grandfather Controller: a truly large slide rule 30 cm across, and still identical in design to the Three others. This one is anything but common; in fact I’ve never seen anything like it, nor can I find any mention of it on the web. Naturally, I added it to my collection post haste, and now there were four!

Four Controller circular slide rules

Read the full article about this mysterious giant Controller on my HOC web site.

Pretty as a picture

June 6, 2019 / Nathan Zeldes / 0 Comments

The circular slide rule developed around 1920 by Jules Arnault and Louis Paineau comes in a wooden frame, to give it durability and ease of use; but it is so pretty you can – and I did – hang it on your wall!

Arnault-Paineau slide rule

Aside from being pretty, this is an ingeniously designed and very well-made calculator. You can find all the details in this new article on my History-of–Computing site.

Enjoy!

The spirit of a fractal!

June 4, 2019 / Nathan Zeldes / 0 Comments

Here is a photo of the Jerusalem central bus station, a large blocky building at the entrance to the city.

Jerusalem central bus station

So, maybe it’s just me, but whenever I see it I get reminded of a mathematical construct – the Menger Sponge, a three dimensional fractal. Judge for yourself:

Menger Sponge

OK, OK, the bus station is not a true Menger Sponge, but its structure definitely evokes the essence – the spirit, if you will – of that fractal.

And yes, I am a geek. Lucky me!

Photo credit for Menger sponge: David Rosser under CC license on Flickr.

Badalamenti’s Factorization slide rule

January 15, 2019 / Nathan Zeldes / 2 Comments

The Badalamenti factorization slide rule

One of the strangest slide rules in my collection, this ingenious Italian device from the 1950s allows you to factorize numbers into their prime factors in an instant. Just move the “Bull’s eye” cursor to the number you wish to examine and the crisscrossing lines and symbols line up to give you the answer.

Check it out on my History of Computing site!

Solving the machinetta’s bug

September 7, 2018 / Nathan Zeldes / 0 Comments

I was at this coffee shop and saw the two machinettas. Of course I didn’t buy one – as coffee lovers, we have all the machinettas we need at home – but I did notice how the pair represents two different solutions to a small but important design bug that the classic machinetta had subjected coffee drinkers to for ages.

Macinettas

The problem is seen below. The original design from Bialetti, who invented this useful little coffeemaker, had the metal block that the handle is bolted to, marked by the red arrow in this photo. This block was just the right size and place to scald your finger when you grab the handle.

Machinetta - bad design

Photo credit: Dan-Martin Hellgren under CC license on Wikimedia Commons.

The two machines I’ve sighted solve this problem in two different ways frequently seen these days: the one at the left below leaves the offending hot block in place but provides a dent in the plastic to keep the finger away from it; the one on the right covers the metal with plastic all the way.

Machinetta handles

I can’t think how many times I got burned before someone at the factory decided to spare the users this pain…

A homebrew Single Sideband transmitter

February 13, 2018 / Nathan Zeldes / 0 Comments

This new article on my Possibly Interesting site is strictly for radio amateurs and other geeks: a photo-essay depicting circuit and construction details of the SSB transmitter I’d built a long time ago. What makes it interesting (other than the nostalgia of vacuum tubes, that is) is the prevalence of improvised, scavenged and military surplus components – necessitated by the paucity of the component supply (and funding) in the Israel of those pre-internet, pre-Startup Nation days.

Homebrew SSB transmitter

Enjoy!

Meet a Mathematical Inventor!

December 12, 2017 / Nathan Zeldes / 0 Comments

This is Jaen-Antoine Lafay’s Hélice a Calcul, a rather unusual logarithmic slide rule. But Lafay himself, its inventor, was just as unusual, not to say quirky… a fascinating lone innovator waging war on an indifferent world.

Lafay's Hélice a Calcul

To illustrate, here is a section from Lafay’s marketing brochure:

Oh, routine! What wrong do you not do, firstly to your devotees who, to avoid a little effort of adapting to innovative tools and processes, which would render them remarkable service, are unwilling to budge from their old deplorable habits,… and then to these poor Don Quixotes who, in believing they might overcome them, only bruise themselves against your incredible force of inertia? And yet, poor fool that I am, with the present brochure I resume a battle that I should have abandoned, moved again by the illusion that I may end up victorious.

See what I mean? And yet, he was an innovative entrepreneur, and you may enjoy the new article I devote to him on my History of Computing exhibition.

Enjoy!

Lieutenant Brenske’s Marsch-Zirkel

May 4, 2017 / Nathan Zeldes / 0 Comments

In the days before GPS, Google Maps and Waze, people used maps; and to figure how long it would take to get from A to B on a map, you could make excellent use of a Marsch-Zirkel, or march compasses… like the lovely device described in this new article on my History of Computing exhibition.

Lieutenant Brenske's Marsch-Zirkel

Dating back to the late 19th century, this ingenious little tool helps you figure the distance and the time to cover it – with infantry or cavalry.

Take a look!

Mind the footprints!

March 12, 2017 / Nathan Zeldes / 0 Comments

An important element of everyday product design that is all too often ignored is the footprint of an object.

I mean, look at these two electric kettles, which are very common kitchen appliances. They serve the exact same purpose; they use the exact same technology; they have the same water capacity.

Electric Kettles

But there’s a big difference: the one on the right has a sensible, compact cylindrical form. The one on the left, by Kennedy, flares at top and bottom, so its footprint – the counter-top area it requires – is some 45% grater than for the Graetz kettle beside it. Kitchen counters can never have too much free area; the designers at the Kennedy company have wasted some of that area for no good reason at all, simply to show off their “artistic originality”.

I see this cavalier attitude to footprint in many products, and it always annoys me… why can’t these people think of their users?