How To Spot A Psychopath

If you had to name one electrical component that just shouts “mad scientist”, the knife switch would be that component.

(I’m not counting the Jacob’s Ladder as a “component”, here.)

Connecting lightning to your not-yet-animated monster, activating your death ray, powering up the time machine; all jobs for a big old two-blade knife switch.

Knife switches have plenty of actual practical uses in the real world. Even small ones can switch very high current, their position is obvious at a glance, and they can put up with a lot of abuse. They’re obviously not a great choice for high-voltage switching, but they’ll usually actually do that very well too - you just have to stay away from the live bits.

(Knife switches made for really high-voltage operation often have special spring-loaded doodads that stay connected as you raise the knife-bar, then snap up very quickly. Their purpose is to break the contact very rapidly, so you don’t pull an arc between the terminals.)

So naturally I had to get one. And not one of the little plastic science-classroom versions with binding posts or spring terminals; I wanted something beefy, as were and still are used to isolate radio gear from the big lightning-attracting antenna outside. A knife switch also makes a dandy automotive battery isolator, but I didn’t want one of those, either.

After a year or two of e-mails from my saved eBay search, I found just the thing.

This handsome object cost me $AU28.11 delivered, which I thought might have been a bit too much, until it arrived. I now realise I got a bargain. This thing’s way cooler than I expected it to be.

All of the terminals and contacts work OK; a couple of the hefty terminal screws were seized and remain tight after cleaning and oiling, but this is a perfectly functional piece of gear.

The Bakelite-slab base is only about 14 centimetres square (5.5 inches), but the whole assembly weighs about 1.86 kilos (4.1 pounds). And it’s surprisingly complicated.

Your standard two-blade knife switch is simple enough. It’s either a dual-pole, single-throw, or a dual-pole, dual-throw (if you don’t know what this means, check out the Wikipedia article on switches).

This thing, in comparison, is a freakin’ logic puzzle.

It’s got six terminals, and two separately hinged - but electrically connected - blades. The worn (and now lightly polished!) wooden handle is in two parts, too, one for each blade. But the two handle parts form a rebate joint.

This makes it possible to have both blades down, both blades up, or only the left blade up. But, because of the rebate joint, you can’t have the right blade up and not the left.

Let’s number the terminals clockwise from the one at the bottom right of this picture. So the one to its left is terminal 2, terminal 3 is the one on the back connected to the bases of the blades, and so on to number 6, which is partly obscured by the wooden handle in the above picture. Pay attention, there will be a test.

With both blades up, terminals 1, 2 and 6 are connected to nothing, and terminals 3, 4 and 5 are connected to each other.

With the right blade down and the left blade up, terminals 1, 2, 4 and 5 are disconnected, while 3 is connected to 6.

With both blades down, terminals 1, 3 and 6 are connected to each other, and terminals 2 and 4 are connected to each other; only terminal 5 is no longer connected to anything.

(If you can’t quite see how that is the case, note that the middle section of the left blade, the lower one in the above picture, has a copper sleeve around it that’s insulated from the blade itself. When that blade’s down, the sleeve connects terminal 2 to terminal 4, but not to the blade itself.)

Oh, and terminals 1 and 6 are connected to the blade contacts via a couple of bits of might-perhaps-be-fuse-wire-but-probably-isn’t. So you could easily connect either or both of them to some other part of the assembly, if you wanted.

(Does anybody know of a piece of software that’ll take a description like this - “in state A, these parts are connected, in state B, the situation changes to this”, et cetera - and will then draw you a diagram? I started drawing it out by hand in a flowcharting/circuit-diagram program, but then realised I had no idea how to draw these crazy ganged switches.)

The baseplate bears a little oval plaque that says:

(It just occurred to me that the switch could easily have been used for switching railway signals of some sort. The rebated handle interlock could be for something like preventing green lights for both directions on one line.)

I actually will use this switch as a switch, from time to time. But when it’s not in use, I think I’ll hang it on the wall somewhere.

As a number of readers, Gerard Ryle’s blog and my saved Google News search have informed me, Tim Johnston, former proprietor of the dramatically-failed magic-fuel-pill pseudo-company Firepower, recently flew back into Australia.

I am not alone in being entirely unable to figure out why he did this. Tim was quite successfully hiding from his creditors overseas, but then decided to waltz back into the country using his own passport. ASIC then told all of the airports to not let him out again. And then he surrendered his passport. But then, last night, he went for a little drive, evading process servers.

Don’t worry - I’m sure we’ll catch him soon. I mean, it’s not as if there are many places to hide around here.

UPDATE: And now we hear that Johnston allegedly used a forged letter from ASIC to assure potential investors that he was not in fact being investigated, and had only fled to London for a holiday, or something. Which is kind of like discovering that John Dillinger was also guilty of failing to pay his council rates, but the more charges the merrier, I suppose.

UPDATE 2: The process servers managed to locate Tim and give him the order to appear at a civil hearing, which the Firepower liquidator hopes will lead to criminal charges. He actually turned out to be pretty easy to find, because he obligingly turned up in another court to ask for his passport back.

Most people have seen stupid “copy protection” on Web pages, where some message about copyright or something pops up when you click the right mouse button. This is supposed to stop you from wickedly making another copy of some portion of the data that has already been stored on your own hard drive when your Web browser asked the server for the page, and the server cheerfully sent it.

(See also, people who make Web sites and then demand that you not link to them.)

Via The Daily WTF’s most recent instalment of Error’d, though, comes what may be the Greatest BS Right-Click Warning Ever:

Every listing from this seller has this. Just scroll down to the main product description and click your wicked pirate terrorist right mouse button somewhere on it, and you will immediately receive your very own copy of this fascinating alert box.

Right-click over and over! Send dozens of “reports”! Wheeee!

In case you’re new to all this, and wondering: No, nothing’s actually being “recorded” or “reported”. The alert is created by a little snippet of JavaScript that tells the browser to do something when you release the second mouse button. In this case, the code pops up the alert with the stupid message.

It works in the same way as this, which also pops up an alert when you click on it. (It’s also not unlike the system used for “security” by the subjects of another Daily WTF story.)

Unless you’ve got JavaScript disabled, that is, in which case it won’t do anything at all.

If you throw caution to the wind and view the source of any of this eBay seller’s item pages - using that advanced hacker tool, your browser’s “View” menu, or perhaps just by right-clicking somewhere else on the page but the main product description - you’ll see that the high-powered enterprise-computing code that creates this very serious warning is part of a rather long single line.

As entertained DailyWTF commenters have observed, that line is, in the case of the listing I looked at anyway, a magnificent 40,076 characters in length.

Some text editors will choke on lines longer than 32,768 characters, you know.

So that’s even more security, right there!

Here is how to make a (very) simple wood protectant and polish. I’ve had occasion to use this stuff a couple of times on things about which I’m working on blog posts [update: this knife, and this knife switch], so I thought I’d do a quick post about it.

1: Get some beeswax. It’s easy to find cheap on eBay; beekeepers often seem to cast the stuff into bricks in margarine containers or something, and they usually seem to filter and wash it too.

(I got a couple of big 0.95-kilo bricks of beeswax for less than $AU30 delivered a couple of years ago, but that seller doesn’t have anything on offer right now.)

2: Get some ordinary light mineral oil. Those little bottles of clear “all-purpose oil” or “sewing machine oil” you can get from the supermarket will do nicely.

3: Melt the wax and mix in the oil. Beeswax melts at a bit more than 60°C, so you don’t need a lot of heat. If it’s smoking, it’s too hot.

You’ll probably want a ratio of about five or six parts oil to one part beeswax, by volume, but there’s lots of room for experimentation. To play with the recipe, or if you only need a little polish, you can make it in an old spoon, heated with a small flame or boiling water under the spoon.

This simple polish is non-toxic, food-safe and won’t go rancid, and has the same pleasant faint honey smell as the wax. It’s easy to vary the consistency from thick and waxy - but not as thick and waxy as straight beeswax, which doesn’t really work as a polish by itself - to liquid-at-room-temperature. And it really is the work of a moment to make this stuff.

A little of this polish goes a pretty long way, so you can make as little of the stuff as you actually need, instead of buying a bucket of commercial polish that you’ll never use all of, or a ridiculously overpriced tiny container.

UPDATE: I have now discovered that this stuff also makes perfectly good lip balm.

That’s right - it’s a floor wax and a dessert topping!

When I finally got around to making myself some thermite, which like all right-thinking people I’ve been meaning to do since about the age of 10, the thing that surprised me was how bright it is. The combustion temperature of standard aluminium/iron-oxide thermite is about the same as the operating temperature of a light-bulb filament, and that’s how bright the whole burning mass shines.

Here’s a nice video of the process of thermite welding, which has for more than a hundred years been used to join train tracks together.

There are lots of other thermite welding videos on GooTube, though not all of them let you see the aftermath, when they remove the crucible, knock the mould sectors away and shape the still-glowing weld.

People who do this trick frequently clearly get rather blasé about it after a while, and hang around close to the crucible, or even do stuff like lighting cigarettes off the top of it. I don’t think that is actually a very good idea, unless you are absolutely 100% bet-your-eyes-on-it certain that there’s nothing on, or even under, the crucible that may unexpectedly flash to vapour when heated to these extreme temperatures.

Classically it’s water, or even damp stone, that causes thermite to “explode”, but many other substances will too. As I’ve mentioned before, many metals will boil at thermite temperatures, and there are all sorts of other usually-considered-inert substances that also don’t play well with thermite.

Like, for instance, asbestos. The molten iron from a thermite reaction may have cooled enough to not even melt an asbestos mat, but if you put a chunk of asbestos in with the thermite, it will definitely melt and quite possibly boil.

(This ought, at least, to render the asbestos harmless. Asbestos is basically just silica in an unusual shape, so if you melt it and then allow it to cool, you get a lump of non-toxic glass.)