(no subject)

[moominmolly]

Does anyone around here have the tools to break a Kryptonite U-Lock? Not a bic pen; I'm talking actually destroying the lock and not the bike that's in it.

Unrelated: My email works again! Hooray!

Comments

[bkdelong.livejournal.com]

I have a friend who might...let me reach out to him.

[szasz.livejournal.com]

I don't know what will do it besides an acetylene torch.

[inahandbasket]

I have an angle-grinder that would probably do it.

[sol3.livejournal.com]

In other words, she wants someone with an acetylene rig, eh? A shame I doubt i'm allowed to fly with mine.

[moominmolly.livejournal.com]

I was figuring SOMEONE would have an angle-grinder. Hooray!

Now, can I borrow you some time? :)

[moominmolly.livejournal.com]

Dude you would be my hero.

Actually, you're already a little bit my hero. :)

[inahandbasket]

It's possible. Definitely easier to lend you the angle-grinder. ^_^

[inahandbasket]

It should be noted that you'll need electrical power to run said angle-grinder, so if said bike's not near an easy power outlet it could be a problem.

[moominmolly.livejournal.com]

I have a power inverter and a car, is what I was thinking...

I've never used an angle-grinder, but I can generally be trusted with tools (despite appearances to the contrary). Think it'd be okay?

[the-xtina.livejournal.com]

Hooray email!

[inahandbasket]

It's a pretty hard to mess up tool, I wouldn't be worried about it. Just so long as you don't hurt yourself with it! (Wear safety glasses and watch for kickback.)

[(Anonymous)]

as the aforementioned friend:

I sent mail to your @livejournal address. If that doesn't get to you, post here, and I can put in a little more effort. (we run in the same circles, so it shouldn't be hard to find someone with your actual email address.)

I'd be surprised if your average car inverter could run an angle grinder. There are other methods. let's talk. :)

[moominmolly.livejournal.com]

Sweet!

[ectropy.livejournal.com]

Get someone at MIT to steal you a cooler of liquid nitrogen, carefully pour liquid nitrogen onto lock until very frosty, and strike with hammer?

Oh, and if you do this, I so want to be there!

[dilletante.livejournal.com]

tempted to try this just because i've always heard it works but never seen it.

[dilletante.livejournal.com]

might worry about messing up the bike...

[moominmolly.livejournal.com]

Would you believe that was my first thought? Excitement at the idea of getting someone to use liquid nitrogen on it? :) I would be delighted to watch that delightedly with you!

Go Go Science Grrls!

[spike.livejournal.com]

E., last night at bathtime: "OWIE! This bath is so hot I need LIQUID NITROGEN to cool it down!"

Re: Go Go Science Grrls!

[moominmolly.livejournal.com]

I love that kid!

[spike.livejournal.com]

I wonder whether "poor man's LN2" (alcohol supercooled with dry ice) would work, too. (At -109°F, it's cold enough to do the "shattered flowers" demo, but not nearly as cold as real LN2 at -320°F.)

[inahandbasket]

eh, drape a piece of canvas over the bike where sparks might hit. ^_^

[palmir.livejournal.com]

Dremel + new cutting disc + 5 minutes = cut lock + dead cutting disc (unless you're talking Evo series or higher - I've never had to cut one of those, but as far as I know they use the same metal, just more of it, so it'd take more time and cutting discs).

[palmir.livejournal.com]

I keep hearing the liquid nitrogen idea, but never seen (or heard of) it in practice. Because if you have ready access to liquid nitrogen, why would you be stealing BIKES?

[moominmolly.livejournal.com]

Oh wow! I wouldn't have thought a Dremel would do it, but I believe you!

[cuthalion.livejournal.com]

A survey of smaller angle grinders on amazon says they're typically 6-7.5 amps, which is about 700 watts.

A car battery can certainly deliver this much current (they can typically do stuff like 6600 watts for short periods of time) but few inverters can do this much (a "regular" one is probably around 100 watts, and you can get others that do more. A 750 watt inverter can be had for only $50!). You'd have to clip it directly to the battery directly, since cars typically have a fuse on the cigarette lighter that will certainly not let 700 watts through.

How far is it from an outlet?

Surely some burner around there has a generator or deep cycle marine battery and high capacity inverter you could borrow!

[haptotrope.livejournal.com]

angle grinder! in under 60 seconds.

Wheee!

[palmir.livejournal.com]

I've done it myself, including breaking a disc or three on a single lock (properly securing the disc helps with the not-breaking). It works, but it's not ideal.

Note that this method (and, I imagine, the angle grinder) will make the lock VERY HOT, especially near the cut.

[moominmolly.livejournal.com]

It is in fact a 750 watt inverter that I have, I think! I will go investigate and find out how far it is from an outlet, because that's clearly superior -- it's in a parking garage bike cage.

[cuthalion.livejournal.com]

Wired Dremels are only around 1 - 1.5A which is still on the high side for a regular car inverter, but maybe worth trying (but be prepared to buy a new fuse for your accessory power port!)

Conservatively assuming 10 minutes to cut through a lock, you will probably want to bring a couple sets of AA on a cordless Dremel. And you'll probably also get better results with NiMH rechargeable, which don't degrade in performance in high draw situations as badly as alkalines do.

[cuthalion.livejournal.com]

I can confirm that you can probably burn yourself while cutting a kryptonite with an angle grinder.

Also: maybe have someone else do it when it's a little dark and get a tripod. The angle grinder throws off a ton of sparks. They didn't damage the paint on my bike; they are basically iron filings with almost no mass, so little heat.

[cuthalion.livejournal.com]

Oh ho ho!

Electric motors typically have a momentary higher draw when starting, so it's conceivable that it'll blow a fuse anyway, but it seems like it may work for a 6A angle grinder. 7.5A is more like 825 watts.

Please post updates!

[cuthalion.livejournal.com]

Okay if you have a fancy inverter, it almost certainly has clips for the battery so: yeah use those, and you should be fine with a Dremel. Though it will seem like it's taking forever.

If you can get the angles to work without this endangering your bike, I've heard a car jack works pretty well too.

[srl.livejournal.com]

Is the lock's mechanism broken, or did you lose the key?

[moominmolly.livejournal.com]

The key is half broken off in the lock, and this seems to render it inoperable.

[cuthalion.livejournal.com]

I didn't do this when I cut through the kryptonite on my bike with an angle grinder, and didn't have any blemishes on my bike as a result. I was not pointing most of the sparks at the frame (even in cramped quarters you'll have a little room to adjust).

But they have very little mass (smaller than sand) so the don't hold enough heat to really do anything to the paint (which they're only touching for the shortest of time as they bounce off), and while they are sharp they don't have very much momentum. I think that acetylene cutting makes much larger hotter sparks than grinding.

[beah.livejournal.com]

Have you tried using a magnet to pull the broken key bit out of the lock? If it worked, you could then pick the lock or use a spare key. The rare earth magnets are pretty fierce and might do the job.

[dilletante.livejournal.com]

it's my bike. i haven't even tried pulling it out with pliers; but it broke halfway through turning it, and it broke because the lock is slightly rusted and very stiff, so i'm skeptical of the chances of success. might douse it with wd-40 and then try pliers.

[ectropy.livejournal.com]

Because, I presume, this isn't about stealing bikes. Rather, it's about freeing a bike from a lock with no key and possibly a jammed keyway.

[palmir.livejournal.com]

Well, right. You just mostly hear about how locks are opened in order to steal the bike, not how to free one's own bike. In the former, time and inconspicuousness are important factors; not so much on the latter. Which would make it an ideal candidate for liquid nitrogen, really.

[palmir.livejournal.com]

Better if you have aerosol TriFlow, but lube + pliers can work and is relatively painless.

[cruiser.livejournal.com]

I pretty much assume any job will result in one or more dead cutting discs.

Additionally, as I mentioned when David was talking about drilling the lock, I have the equipment necessary to do so. But since I'm in DC & y'all are in Boston, I can offer neither my services nor my equipment. Which is too bad, because I really enjoy destructive removal with power tools (or without, come to think of it - hitting walls with a sledge hammer is fun).

[cuthalion.livejournal.com]

I broke off my key by not pushing it all the way in; the lock then turns part way and gets stuck. If you try too hard to turn it then you get to use an angle grinder.

I think this happens a lot with the post-bic kryptonite lock design :(

[chenoameg.livejournal.com]

I have some wicked long extension cords.

[frobzwiththingz.livejournal.com]

Many years ago i actually tested this urban legend. It turns out that it you can indeed shatter the lock mechanism of a kryptonite bike lock by hitting it with a hammer after soaking the lock in LN2 for a while. But it turns out to be *just as easy* to do without using any LN2 at all.

[dolohov.livejournal.com]

6A is a lot of juice; you might want to check what your cords are rated for.

[gravitrue.livejournal.com]

I expect you have this solved by now, but if there's enough clearance, one typical method I've heard of is to stick a car scissor jack inside the U and just crank away.

[cuthalion.livejournal.com]

6A is not a lot of juice. Most three-prong extension cords are rated for 13A or 15A. Even a 16 gauge extension cord 100 ft long should be able to handle 10A safely.

However, If you have a real long cord, it's good to uncoil it before drawing any significant power through it though - I once melted the insulation off a cord by running a computer & projector (Probably around 6-7A) on a (fat enough) cord on a spool (for 10 hours, though).