h a l f b a k e r yQuis custodiet the custard?
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The typical bike lock is not the most sophisticated device.
Typically, they're a U-shape or chain made of ~10mm steel,
hardened if you spent wisely. Most commonly these are
defeated by cutting right through them with a cordless
angle grinder and a cut-off wheel. Such things are
fantastically
efficient because they're made of materials
harder than steel.
Materials harder than steel are one of the things that make
steel so popular, with silicon/tungsten carbide you can
slice right through steel and make it any shape you like, all
it takes is horsepower.
If you want to slice through things ending in "carbide"
things get tricky. Diamond and cubic boron nitride will do
it, but not at all quickly or easily compared to steel. So can
we make a bike lock out of tungsten carbide? Well, yes.
But then you could smash it with a hammer.
So. Take your favorite bike lock shape. Make it tubular,
rather than solid. Fill the tube with an epoxy resin mixed
with big/small chunks of carbide and some steel powder
and you're done.
The tube shouldn't be anymore vulnerable to forcing with
hydraulics. Cutting with a normal wheel will get through
the steel and then bog down* in the carbide epoxy mix.
Even a diamond saw will have trouble, since the hard
carbide is somewhat flexibly mounted in the epoxy,
leading to a juddering cut, plus, the steel casing is still in
place, and hot diamond dissolves in hot steel.
As a side bonus, the lock should be a good bit lighter.
* dangerously, with any luck. Hopefully, the disk cuts
quickly through a section of epoxy and suddenly catches on
a chunk of carbide. This would shock-load the fragile disk
and shattering may occur. A shattered cut off disk is often
dangerous, but proper PPE will protect the prudent thief.
Chobham armour
https://en.wikipedi...wiki/Chobham_armour
" ... composed of ceramic tiles encased within a metal framework ...". We could tell you more, but then we'd have to kill you. [8th of 7, Mar 09 2020]
https://www.indiego...r-proof-bike-lock#/
[xenzag, Mar 12 2020]
Rapid Bike Theft Device
https://explosives....oduct/rebar-cutter/
[bs0u0155, Mar 16 2020]
Encapsulated Ceramic Composite Armour
https://patents.goo.../US20090114083A1/en
[bs0u0155, Apr 27 2020]
Plastic Armour
https://en.wikipedi...wiki/Plastic_armour
Not a polymer, but has plastic qualities. [8th of 7, Apr 27 2020]
Starlite
https://en.wikipedia.org/wiki/Starlite
Controversial, and intriguing. [8th of 7, Apr 27 2020]
[link]
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You're describing ceramic vehicle armour - Chobham armour <link> - which is Baked and WKTE. |
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Best advice I ever got was to park your bike next to a more expensive one. |
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Looking at the Altor SAF link, it occurs to me that for this
approach to succeed you're also going to need grinder-proof
bike-racks. |
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// does not use reactive armor // |
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We call that "underspecified". |
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//Best advice I ever got was to park your bike next
to a more expensive one// - indeed! I also lock my
bike* with a lock which cost more than the
bike
* my commuting bike, not my nice
bike or my second-best bike |
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When you get your commuting bike on Freecycle like I did, that's not hard. I did have to buy new tyres for it though. |
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Also, I’m not sure this idea would prevent the
car-jack method of breaking u-locks |
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A red-on-yellow cardboard tag with the biohazard symbol and the text "CORONAVIRUS - AWAITING DECONTAMINATION" in several languages should be at least as good as a lock - at the moment ... |
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//Altor SAF// LOOK AT THE SIZE OF THE THING! it's just a
normal lock in a thick aluminum case. |
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I wuz thinking about a very cheap, tubular lock filled
with some substance guaranteed to explode when in
contact with air. One might, perhaps, applaud* when
the thief cuts through it. |
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* while wearing protective clothing, from a safe
distance. |
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To act or not to act, that is the question. Whether tis
nobler in the mind to suffer the grinders and
maliciousness of such vermin, or to bake a simple idea
and blow them all away? For surely, ruffians know they
misbehave and should reap what they soweth. |
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See last link. This thing is totally bonkers. |
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Ha - funny. Didn't notice it. Will delete or fight you
for it! |
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Thermite... white phosphorus... large amounts of
unstable stuff that goes 'bang!' and scatters courage and
various body parts... |
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Yes, the Help file. I know, guv. Off I go.
(plods off to revisit the Help file, yet again) |
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Perhaps the traditional U-shaped design could be
upgraded with a series of free spinning beads
slipped over the U. Hard to angle grind someothat
keeps rotating. The thief could angle their grinder
(heh) 90 degrees but that makes their task much
more difficult and slower. |
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I see no-one's touched the grindr-proof bike lock. Probably
just as well. |
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//a series of free spinning beads slipped over the U// |
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Could work, and carbide beads are simple enough to make,
although getting them tight enough that you can't get the
disk between them could be tricky. |
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Make them asymmetric, with a spigot/undercut, then each bead under/overlaps its neighbour. |
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The ends of the sequence are problematic but could be protected with a thick outer sleeve over the beads. |
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Not sure how well that would protect against having det cord wound round the "U" and then initiated. |
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//Not sure how well that would protect against having det
cord// |
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Was about to write an idea for an explosive faster-than-key
bike lock unlocker. But, a quick google suggests someone
already made one <link>. The good thing about using
explosives to steal bikes in public areas, is that the actual
bike stealing will likely be a minor component of the legal
ramifications. |
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That kind of depends on the neighborhood... |
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//depends on the neighborhood...// |
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True, in the rougher neighborhoods of Philly it would
blend in with the general gunfire. Conversely, over the
river in Camden, extensive firearms experience is so
common that you'd actually draw a small crowd. That's
the sort of place it is. I mean, many people think the
Iowa class battleship parked on the Delaware is retired.
Oh no, that's just the sort of thing you need if you get
into a serious disagreement with the population of
Camden. |
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The importance of this idea goes far beyond just bike locks and into anything with a lock or other grindable/sawable protection on it. |
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Someone with a small safe may want to enhance the combination lock with cut-off wheel resistant tubes surrounding the safe held together by U-shaped locks. |
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Do this at home: "Fill a steel tube with an epoxy resin mixed with big/small chunks of carbide and some steel powder and you're done." |
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The importance of this idea goes far beyond just bike locks and into anything with a lock or other grindable/sawable protection on it. |
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Someone with a small safe may want to enhance the combination lock with cut-off wheel resistant tubes surrounding the safe held together by U-shaped locks. |
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The importance of this idea goes far beyond just bike locks and into anything with a lock on it. |
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Someone with a small safe may want to enhance the combination lock with cut-of wheel resistant tubes surrounding the safe held together by U-shaped locks. |
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Try this with a straight steel tube at a home, if a cut off wheel well not cut through it this is worth a patent search and patent in my opinion. |
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Do this at home: "Fill a steel tube with an epoxy resin mixed with big/small chunks of carbide and some steel powder and you're done." |
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Search the Internet for "how to license a patent" and look up the "Houston Inventors Association COMPANIES LOOKING FOR NEW PRODUCTS." |
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"97% of patents never make any money." Search for that phrase on the net. |
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Search for "most businesses fail within * years" in Google |
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//You're describing ceramic vehicle armour// |
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Yes he is. Except that it's not armor. Or ceramic. Or mounted on a vehicle that way. Or anything resembling ceramic vehicle armor at all, actually. |
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// an epoxy resin mixed with big/small chunks of carbide and some steel powder and you're done. // |
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That's how ceramic armour is constituted; and the device is mounted on a vehicle, though not as an outer casing. |
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It's creating a core resistant to impact and abrasion, with the same mechanical properties as composite armour. |
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To be fair, I'm not putting solid ceramic plates in, and the
patent for that would contain a statment of use. eg
<link>: "protection against blast and ballistic threats. The
disrupting layer includes ceramic particles or tiles that
disrupt the incoming projectile," |
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No mention of resistance to abrasive cutting techniques.
Having said that I remember a safe design on Tomorrow's
world that was chunks of granite in plastic. They had a go
at it with chunks of something like granite in it. They
showed it holding up against a pavement cutter (not sure
what blade they had on, would make a big difference). So
abrasive cutting resistant armor isn't novel, but tubular
armor elements might be. |
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Still, the way US patents are, I would never attempt to
file one for anything. Even though many universities
encourage such efforts and have staff to facilitate
applications etc. The practical experience of people I
know is brutally discouraging. My understanding is that it
is the patent holder's responsibility to defend their
patents, that is, if Megacorp infringes your patent, you
are obliged to a: notice and b: provide legal challenge. |
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Since Megacorp isn't going to advertise their activities,
and since legal activities are time consuming and eye-
wateringly expensive, individuals of normal means can't
hope to challenge infringement. Several academics I know
have had patents blatantly infringed (in one case a letter
informing them of the intent to infringe), all sought help
from their Enormo-Mega Universities. In all cases the
Universities did nothing. As it stands, your only hope is to
go via the secret-sauce route. |
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// chunks of granite in plastic. // |
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That was an updated version of D.M.W.D.'s "Plastic Armour" <link>, which used Penlee granite chippings because of its enormously high crush strength. |
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The original used bitumen, later compositions used a more sophisticated formulation to deliver both thermal, abrasion and impact resistance. The WW2 form was quite flammable - unacceptably so for some applications, but since it was mostly used on the exterior of ships (where water for firefighting is usually in plentiful supply), and was in other ways superior to its competitors, it was widely adopted. |
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It stands up very well in comparative tests against more modern alternatives. |
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Interesting. A modern version with mineral of choice, carbon
fiber and silicone could be applied to practically anything.
Could even make an new line of bouncy ovenware. |
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Maybe you want something with properties similar to Starlite <link>, but with a silicate or carbide ceramic embedded in the matrix ? |
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Whatever Starlite is, it's properties aren't great for most
applications. Speculation seems to revolve around it being a
carbohydrate, which makes sense. People have melted steel
in carbonized bread. If you added a dense carbide, it would
all fall out of the matrix as it expanded. Worse, if you
confined it, the expanding behavior would stress the
container tremendously. Especially if there are any volatiles
in there, which I'll bet there is, namely water. |
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We said "similar to Starlite". Something with elastic and intumescent properties, to resist heat and absorb impact, but capable of mechanically bonding the rigid particles to deal with abrasion. |
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So there's this fence / wall thingy on our southern border
that wants to examine some of this technology... |
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kdf, thanks for that. I read it. Wish I hadn't, feels like it was
written by 16 year olds. Any how, like a lot of science, they
published what worked, namely resistance to angle grinder
abrasive cut-off wheels and a water jet. Now, the graph
showing stress/strain shows transition to plastic deformation
at <20MPa. That's 40 FOLD less than steel, so, I reckon you
could cut it with tin snips, maybe even kitchen scissors or a
utility knife. |
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You could go the other way. Make the bike lock with a surface formed of spinning angle-grinder blades, powered by a small internally mounted petrol engine within the lock. Now anyone trying to touch the bike lock will get their touching device grinded off. |
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Make sure the lock doesn't touch the bike though. |
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