Unlock 4 Digit Cable Lock

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Introduction: Unlock 4 Digit Cable Lock

About: I'm a Bio-medical researcher stationed in Chicago. Graduate of Loyola University (Chicago) class of 2014.

My brother's friend found my 6ft On Guard cable lock and promptly reset the combination to something he was too lazy to remember. so I cam up with this method to find the lost combination and save the world (my world)
This is the semi-hard way. it's not the exhaustion method (trying every possibility) but it takes a little brain power and reasoning.
I know there's a lot of stuff on line about how to unlock a cable lock but these methods only work for the drug-store variety of locks that have low tolerances and a lot of wiggle room. (i'll explain why later) This one works on the nicer kind. the ones that have half inch braided cables and much tighter tolerances.

Footnotes:
Don't try to use this to steal a bike. It won't work. you can't put enough tension in the system to feel the shape of the disc using your muscles while rotating the tumblers. If that's your reason for being here, kindly piss off.

Edit (2014): I have since retired this lock. After moving to the Roger's park 'hood of Chicago, it has become rapidly apparent that cable locks are not only easy to crack but easy to cut. Kryptonite's higher-end locks still prove to be beyond my ability to crack. their tolerances are tight making the lock seize under tension. the only way to open one seems to be through exhaustion. anyone good with arduino want to make a robot?

I now use a keyed on-guard U-lock.

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Step 1: Understand What's Inside

inside there are four rotating plates with a notch the shackle to slide through. When you scramble the lock, the plates slide to block the shackle from coming out.

Step 2: Tension the Lock

I wrapped the lock around a chair (pictured) sliding the cables apart increases tension in the system. you need tension to press the teeth of the shackle against the lock discs. this lets you feel the shape of the discs better and decide when one of the teeth isn't pressed against steel disc and is just hanging out in open air.

Step 3: Rotate the Tumblers

Start with the tumblers that are hardest to rotate first. these have the most tension. tension makes the disc's shapes easier to determine.

Now, there's a couple of things to look for. companies tend to put notches in the discs to give would-be thieves a hard time so you need to look for a union of events.
     -The tumblers will be really hard to turn under tension. When it's all of a sudden easy to move, that's an indicator you have one of the numbers
     -A previously loose tumbler just got hard to move. this means that tension was just taken off of one of the discs and now the shackle's teeth are pressing harder on another disc. 
     -Any consistent response from the lock that is larger when one number is reached than any other. this can be a sensation or a sound. in more expensive locks (like mine) you'll feel (and excuse the hokey onomotopeia) griiiiiiiind...click...griiiiiiind.....jerk....CLICK. the last click (if you didn't guess) was likely the disc reaching it's correct place and a tooth popping into the gap.
     -It's harder to leave a number than it was to get to it. a tooth is in the way of the disc sliding locked again. stop touching it. you've probably got it.

None of these are sure fire on their own. There's a lot of money in making sure you can't figure our how to open a lock without knowing the combo. sometimes there are two numbers on one tumbler that seem likely. write them down and try them with the likely numbers from the others.

Step 4: Have Nerves of Steel

When you get it, you'll be concentrating hard and i can guarantee the lock will fly apart. Its going to startle you. Don't make this remove the idea of setting the combo to something you'll remember from your head.

3 People Made This Project!

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56 Discussions

0
muthu2020
muthu2020

6 weeks ago on Step 4

Thanks a lot, I am using step 2 tension the lock and rotate 4 rows continuously one by one finally i was got open my helmet lock pattern.

0
Ron_123
Ron_123

10 months ago

Thank you for this post to give me ideas and confidence. I was trying in light for 15min. Then I turned out the lights and opened an OnGuard lock it in 5min. Unlike some videos that showed the tumblers shifting while the combo digits found, mine did none of that. But I did indeed feel fir the tight tumbler and found its "loose" place.
Great instructable.

0
ChristineC80
ChristineC80

1 year ago

My son's expensive lock was, wrapped around his frame and he couldn't remember the password. I had to stand with the lock over my shoulder pushing against the bike to create tension. I was absolutely thrilled when and kind of surprised when the lock popped open. I wasn't even looking at the numbers just listening for the click. Thank you so much for this post!!!!

0
jpulkowski
jpulkowski

2 years ago

Thanks , I forgot the combo Tony lock, I got it open less than two minutes

0
SteveB411
SteveB411

2 years ago

Finally did it. Took 15 minutes to open my son's bike lock after he accidentally changed the combination. When it was HARD to go to the next number under tension, I knew the number I was at was probably the right one (largest divet in the lock mechanism), starting from the last number and moving backwards.

0
emrz87
emrz87

3 years ago

I've been watching videos, reading and playing with my bike lock for hours. Read your post and seconds later the lock popped open and scared me!

0
ChrisB850
ChrisB850

3 years ago

great instruction. I used two chairs to get the tension and opened an on guard lock in minutes. It had been hanging in the garage for years....brand new!

0
cooperhull
cooperhull

3 years ago

It took me 3 minutes!!

0
AshK19
AshK19

3 years ago

Thanks
Great work .

0
BynS
BynS

3 years ago

Your a legend... Worked within 2mins. Tension made the clicks loud

0
IgorG36
IgorG36

3 years ago

You magnificent bastard... Got it in one minute, knowing partial combo!

Good stuff :) Thank you

0
TommyT28
TommyT28

3 years ago

0005 is what I figured out. Took a couple minutes.

0
Col.C
Col.C

3 years ago

Wow that did the trick in less than 2 minutes.

THANKS!!!

0
TedM33
TedM33

3 years ago

Beautiful.man just beautiful. Took me aprox. 3 minutes , the more tension the quicker it is done. Period. Thanks brother!

0
EthanH59
EthanH59

3 years ago

Thanks man took me 1 minute to figure it out :)

P.S.

this also works with word locks

0
BorborO
BorborO

4 years ago

It worked... And it did indeed open, violently. So violently it hit my face and chipped the right lens of my glasses.

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AndreaM190
AndreaM190

4 years ago

Thanks so much, the tension with the chair did the trick! The lock opened before I got all 4 clicks, so I used a flashlight to align everything inside for the code and it works like a charm now. I was ready to buy a new lock too.

0
MishaAustralia
MishaAustralia

4 years ago

thanks man, the chair trick is brilliant, much better then holding down by feet ;-)

In my case, it was one false hit and one good, on each wheel.

What also helped me to find falce spots was rocking each digit on the wheel backward and forward, to feel the difference.

So, definatly the chair, a pen and paper. Write down spots on each wheel, then try each combination of spots(writing each down to prevent repeat.. ;-) )

Best for all.

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0
RolandWayneRobertsJr

Tension IS the answer. Seeing your example of wrapping it around a chair did not quite work, I needed MORE tension. I wrapped this MasterLock 8220 around a pipe clamp as far as it would stretch, after opening the pipe clamps tightener all the way I cut a 2x4 to fit inside the working ends of the pipe clamp. Tightened the pipe clamp stretched the cable as tighter than previous attempts. While it was very hard to rotate the numbers, there was absolutely no doubt when the right number was discovered. After more than several usuccessful frustating attempts I queried Google which led me to Your post, which provided the correct answer. Again I will mention to anyone who may have unsuccessful results even when tried exactly as descibed, the more Tension applied, the more amplified the "clicks" will sound and it will make the wheels much more tight when turning. But there will be ZERO doubt when you turn each wheel and hear the louder "Click".
Thank You for Your post, most helpful