Turning Street Sweeper Bristles Into Lock Picking Tools…For Science!

In between writing for Hackaday, most of us (if not all of us) like to design projects on our own, creating whatever might come to mind. I, for instance, enjoy experimenting with lock picking techniques at industrial, gritty, and real warehouses in Southern California learning how to utilize the resources there, turning spare parts into something completely different.

One such skill I learned is how easy it is to make lock picking sets from discarded scraps of metal. The documentation is found on a personal blog of mine called HackerTrips (we cover our own stuff sometimes). It contains several photos and descriptions of the process involved which I picked up thanks to a hackerspace in Fullerton where local makers dream up all kinds of interesting projects.

The project starts out by walking on the streets, which is a rarity these days. This is because the general modes of transportation now are either a car, a bus, a subway, a train, a bike, or a plane, which puts the attention on the destination at hand rather than peering into the fractures of the road. This means that a lot of the time, people don’t notice the hidden treasures found on the side of the street, including the street sweeper bristles that have been knocked off their edges.


They are usually uncovered within cracks of the concrete where the street machine sweepers gnaw their steel teeth from time to time on the disrupted seams of asphalt, leaving behind battered bits of metal, which are the perfect size for feeling their way into the pins of a lock. Once collected, the steel can be heated up, then promptly cooled in liquid, and fashioned into fingering picks or wavy rakes and tension wrenches. A simple bench grinder can be used to cut grooves in the spring steel into the necessary points, but a handheld file tool does the job too.

Other types of spare metal that are good for unlocking include blued steel fishing tape, stiffening bars that run down the sides of various wiper blades, handle wire from binder clips, and stationary paperclips converted into lock picks. However, the street sweeper approach is one of the most fascinating because it acts like an Easter egg hunt, giving the curious road walker a sense of accomplishment when handfuls of leftover material are transformed into eye-opening, lock picking tools.


Now with great power, comes great responsibility. I wouldn’t recommend going around town, picking every lock nearby, unless it’s for educational purposes…for science! Trust me, you don’t want to show this technique to the wrong person; they will freak out, or arrest you. But raising awareness that lock picking sets can be made with ordinary scraps of metal is a good thing.

Whether you embrace the skill, or are nervous of the consequences, all this project shows is that it can be done. Just a bit of ingenuity transforms a metal bristle that most people have no idea exists for use in an unexpected way.


25 thoughts on “Turning Street Sweeper Bristles Into Lock Picking Tools…For Science!

    1. Picking is a more of an art. Anyone can bump. Plus not all locks can be bumped so, thanks, but I’ll stick with the truly artful picking. When you can’t bump a lock, let me know, and I’ll come pick it.

  1. OK, basic blacksmithing question; why do you recommend hardening the steel (neating and quenching) before filing into shape?
    No problem if you use an electric grinder, but I remember trying to hand file a bit of hardened steel and it was a long, long waste of time. Is road-brush steel more tractable or should I buy some better hand files?

    1. the dipping is to PREVENT heat treating.
      His steel pieces are already tempered.
      the heat from the rapid grinding will ruin the steels temper if not dissipated, making it soft.
      hence the dipping.

      if you are hand filing, i doubt you will build up heat fast enough for it to be an issue.
      it shouldn’t be a problem

  2. Don’t heat or harden the metal, it already has a spring temper. That is what makes it good. There are better materials than listed here, but those are more for artisan work than anything.

  3. When I started reading, I thought, How the Hack? Turns out this is a localized phenomenon. Here the street speeper bristles are plastic and way too thick to fit in any lock.

  4. I recently got a wee bit interested in picking locks, after a few successes with paper clips and parts of a cheap ballpoint pen at work. I decided to make something a bit more useful than the ghetto-Macguyver methods I had used. Went to the dollar store to see what I could find that I thought I could fashion into a decent pick, found some steak knives four for $1. Cut them to shape with my dremel and for a tension wrench I used some old hex keys ground flat. Works well and have held up to my learning.

  5. What about hacksaw blades? I think the MIT lock picking guide (which is great, by the way) recommends them to make picks, if you don’t want to wander the streets looking for material.

    1. Hacksaw blades are usually only hardened at the teeth, the rest is pretty soft steel.

      (They’re actually two prices of steel welded together, high speed steel for the teeth, mild steel for the rest. That’s what the ‘bi-metal’ name means.)

      Blades for power hacksaws are usually hardened all the way though. I think, it’s been a while since I’ve used any, maybe they’re all bi-metal as well these days. Broken ones were good for making scrapers, scribers etc from.

    2. Yeah, I favor hacksaw blades with the teeth ground off. But the spring of the street sweeper blade makes for a great tool for applying torque to the lock. You can even tape it to the door and have auto-torque. (My dad taught me this: he could pick a lock behind his back while leaning against the door talking to someone.)
      I think dremel tools with separating discs do a much better job of contouring the pick face, although they do need some clean-up. They’re fast, and since they have such a small contact point there’s more metal to dissipate the heat so you’re somewhat less likely to overheat the steel.

    1. I pick up roughly five every time I take my dog out for a two kilometer walk. Once you start looking for them, you find them all over the place. Mostly in the gutter, but on the sidewalk and out in the street as well.

  6. The steel straps used on shipping containers is a good route. Also thin spokes from a bicycle wheel hammered flat are very good at this sort of thing, You could also use hack saw blades, however they do break if you bend them too much, they are over-hardened, I recommend using a well used hack saw blade for this, or at least quenching one before shaping them. Also to the comment above, if you have issues filing on hardened steel you need better files or more muscle.

  7. I don’t want to shout “This is dangerous/illegal” but someone needs to.

    In certain states, Virginia USA is one, mere possession of lockpicks is prima facia proof of intent to commit a crime (burglary, B&E, unlawful entry, etc). Caught with these without a state issued locksmith license is two separate felony counts: possession of thief’s tools, and what ever they decide it is proof of. You can not even practice lockspots in this state. So far, no good cases on it have come before state courts to make the law a little less harsh. Even the challenge the ‘license’ part came up against “well, their employer should pay for an apprentice to learn and buy them the temporary license. Cops don’t want to have to figure out intent if they find someone with picks and no license.” When locksmiths spoke up about how they learned before becoming licensed and bonded professionals by making picks and practicing on their own doors as kids, the police and state legislature replied that now the next generation would just have to do things the new way. You know, to make the cop’s job easier.

    So please! Check http://toool.us/laws.html or something else and don’t get stupid.

    1. Australia is similar.

      Lock picking tools are legal, possessing them might not be.

      Playing with them at home is ok (in most states), but being caught in public with them is considered “going equipped to steal” unless you have a good excuse. “For fun” isn’t a good excuse.

  8. I suppose the inverse of lock picking would be to go around adding more padlocks to other peoples’ doors. People would then have no alternative than to carry lockpicks at all times. Heh :)

  9. ive found that the discarded under-wire from women’s bras, easily harvested any time your sister, girlfriend, wife, daughter, or yourself (if you are female or crossdress) pulls the under-wire from a bra to make the bra more comfortable or throws out a bra burn the plastic off one end with a lighter cut it in half grind or file the end that you burned the plastic from into shape and you have both a tension wrench and a rake from one piece of underwire

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