Most commercial and industrial sites are fenced - but are still subject to people easily hopping over the fences to conduct some opportunistic thieving. The usual response is to want to build higher fences and top them with barbwire, razorwire, sharp spikes or perhaps even electrify them.
Unfortunately, many local governments have decided (in their wisdom) to legislate against fences going above a certain height or permitting the use of razorwire, spikes or electric fences. The stringing of 3 strands of barbwire is usually allowed but doesn't prove to be much of a deterrent to a nimble clamberer.
My fence post (fence 'post' get it?) is to have the fence topped with a tightly-packed series of free-spinning metal 'wagon wheels' along a common axis. If each of these wheels was 40cm (18in) or bigger, closely packed together and free-wheeling enough they would prove to be very difficult to climb over, at least for the casual thief walking by. It is not going to deter the serious professional armed with bolt cutters, etc. but will certainly slow down the casual scumbag more than would a piddly 3 strands of barbwire. The wagon wheel fence would perform this function without giving the local council conniptions about having high-voltage electrics or spools of razorwire which could hurt the dears.
The 'wagon wheels' don't really even need the rims on them as the tapered spokes alone should be enough. This would make the corners easier to build where you would have to use a gentle radius rather than right angles. The advantage of rims though is that they'd be harder to jam from spinning and don't provide any handhold. Then I'd optionally slather the whole thing with thick, gooey axle grease.-- AusCan531, Mar 15 2012 Wagon Wheels http://en.wikipedia.org/wiki/Wagon_Wheels [hippo, Mar 15 2012] NCOTAASD http://www.nicecupo...evious.php3?item=18Much nicer Wagon Wheels link. [pocmloc, Mar 15 2012] all this time I thought [hippo] meant THESE wagon wheels... https://www.google....jT5KYBsfd0QHa1YSvCA [xandram, Mar 16 2012] Wouldn't people just eat them?-- hippo, Mar 15 2012 Some security fences are like this: they have a horizontal rod at the top, on which are mounted spiked wheels. This makes it difficult to get any purchase on the top of the fence, and also makes it difficult to use a blanket or coat to "pad" the spikes.-- MaxwellBuchanan, Mar 15 2012 Eating the fence is surely a hazard, but any intruder who had just consumed their way through one or two giant wagon wheels is going to be pretty easy to catch I would have thought.-- pocmloc, Mar 15 2012 [pocmloc] Ah yes - of course. Ignore my previous concerns about the security of this fence.-- hippo, Mar 15 2012 I would think pizza-cutters placed along the top would work well! sp: deer / or did you mean not to hurt the dear intruders?-- xandram, Mar 15 2012 This would work for deer too - just not the [Alterother's] infamous teleporting deer, of course.-- AusCan531, Mar 15 2012 What about Winged Monkeys ?-- 8th of 7, Mar 15 2012 I don't think they'd stay on the top of the fence.-- MaxwellBuchanan, Mar 15 2012 // just not the [Alterother's] infamous teleporting deer, of course. //
A fence constructed of running motorcycles might be effective against Blink Deer, and even if it wasn't it would still be interesting to look at.-- Alterother, Mar 15 2012 Hmmm, perhaps the fencetop should consist of motorized, studded motorcycle wheels. If running slowly, the nearest side to the would-be thief should spin downwards. If running quickly, they should spin the other way to fling the perps into the next suburb. That would be interesting to look at too.
We might even have invented a type of 'cat skeet' launcher for his borgness. (sorry, I meant 'His Borgness' - no offense)-- AusCan531, Mar 16 2012 It's actually 'Their Borgnesses', I think.
I'd recommend Dunlop Motocross tires. Very chunky, long wearing. Good sidewalls.-- Alterother, Mar 16 2012 And on those rare occasions when they're being sincere: "Earnest Borgnine"? If they ever win an argument with you: "Victor Borga"?-- AusCan531, Mar 16 2012 //Wouldn't people just eat them?// hah.
[marked-for-tagline]-- po, Mar 16 2012 ^seconded.-- Alterother, Mar 16 2012 xandram's suggestion of pizza cutter wheels (even if they were 18 inches in diameter) would be much cheaper than wheels that consist of spokes and a rim.
I would suggest that mere unsharpened metal disks would work nearly as well, and involve less risk of injury to installation and maintenance personnel than oversized pizza cutters.
For maximum cost effectiveness and longevity, they would simply be circles stamped out of galvanized sheet steel, and then have their cut edges treated to prevent rust.
Also... I think it would be more effective if used in combination with the aforementioned three strands of barbed wire. So you'd have, in order from ground upwards, the main part of the fence, then the barbed wire, then the wheels.-- goldbb, Mar 16 2012 hmmm, picturing a razor edged pinwheel design using wind to electrify the fence... and liking it.-- 2 fries shy of a happy meal, Mar 16 2012 Hmmmm, you seem to know a lot about this topic [bigs]. A suspiciously awful lot.-- AusCan531, Mar 16 2012 A friend-of-a-friend found a loophole. He mortared intact, but fragile, glass ornaments onto the top of a wall. They were not sharp (and therefore not unlawful), but would immediately become so if anyone tried to climb over.-- spidermother, Mar 17 2012 Good idea [spidermother]. I bet where electricity is outlawed, I would still be allowed to run my (weakly constructed but scaldingly hot) steam pipes around the top of my perimeter fencing.-- AusCan531, Mar 17 2012 random, halfbakery