Step 1: Tools and Materials

Picture of Tools and Materials
Not many things are required to make this lock.  It's mainly cardboard.

-Box cutter / razor blade
-A cutting mat (so you don't gouge your table)
-Hot glue gun and extra glue sticks
-A compass (the kind used to draw circles)
-Hole punch (apparently this can be used to punch the holes for the washers and such. (thanks to swhitaker2 for discovering this))

-Corrugated cardboard
-Two new pencils
-Large paperclip

Step 2: Making the Rotors

The rotors are the wheels inside of the lock that determine what the combination is. All three must be lined up perfectly so that the lock can, well, unlock.

1) Cut out three circles that are each four inches across.
2) Poke a hole in the center of each circle with the pointy end of the compass, the do the same with the pencil.
3) Draw and cut out a notch in each rotor about 1/2 in. wide at the top. Make sure you don't cut all the way to the center, but at least one inch deep.
4) Cut out two tabs that are 3/4 by 3/4 in. Then cut one tab that is 1 and 3/4 inches by 3/4 in. Scraps of cardboard are good for these kind of parts.
5) Make a cut-out in one of the rotors, about 3/4 inch deep and 1/8 inch wide, or however thick your cardboard is.
6) Attach the tabs to the rotors using hot glue as shown in the picture. Don't copy my layout exactly otherwise the combinations will be identical. Also be sure to arrange the notches so that they're all facing the same direction when you attack the tabs.
skulljo26 days ago
I dont like a thing of instrucable that it take very much time ti load the pictuers.
skulljo26 days ago
I dont like a thing of instrucable that it take very much time ti load the pictuers.
skulljo26 days ago
I dont like a thing of instrucable that it take very much time ti load the pictuers
skulljo26 days ago
I dont like a thing of instrucable that it take very much time ti load the pictuers
skulljo26 days ago
I dont like a thing of instrucable that it take very much time ti load the pictuers

I think the washers of step 4 are 1.25 inches by 1.25 inches, not 0.25 inches by 0.25 inches.

ZachH2 made it!5 months ago

Hey there, I've now made 3 of these with kids! It's pretty awesome. To make it easier for kids to cut and follow along, I created the outlines of a majority of the pieces in Illustrator. I've attached the PDFs I've made here. Thank you!

Combi Lock Base.pngParts 1.pngParts 2.png
ZachH2 ZachH25 months ago

Oops, those pictures weren't exported correctly! Here's the proper ones...

Combi Lock Base-01.pngParts 1-01.pngParts 2-01.png
tardis fan (author)  ZachH25 months ago

Wow, so cool! That's a great help! I'm happy to hear that the kids are enjoying it!

Velin91 year ago
LOL Easy to unlock! Just light it on fire! XD. LOL HAHAHAHA
ThePorsche82 years ago
u did a really nice job! i really want to build it but it looks so complicated. can you give some tips on how i can build it without being worried please.

that will give me a lot of help.
tardis fan (author)  ThePorsche82 years ago
Thanks a lot!

To begin, lay out all tools and materials in an organized fashion on your work surface. Once you're ready to start, take each step one at a time, and don't rush. You can always start over if something goes wrong. Remember to clean up the little scraps that aren't needed off your work surface, because having a clean desk helps a ton.

And believe me: it really isn't nearly as complicated as it looks once you start!

Hope I helped, and good luck!
cool project you should make another that can actually lock a box, And make it smaller because it is huge please try
macrumpton2 years ago
This looks awesome.
I think it might be even better if you used laminated layers of solid cardboard, like the stuff used for cereal boxes rather than the corrugated stuff, as it would be a lot more durable. After all it is a lot of work, so you want it to last.
244 Jake2 years ago
Great post as to how the lock system works, Any way a completed safe could be shown.

Yesterday I received this. Most cool. I do NOT beleive it's evil to show a different way to do the same thing. Even if this was 3 months after YOURs.

Could you do the next step, Please, show how to connect to a door handle. I want to make a big Toy Gun Safe, out of card board, say the card board box a refrigartor would come in..

Big Jake
samaw1293 years ago
hey, im back,
any way to add a door? trying to win a bet that i built a cardboard safe
tardis fan (author)  samaw1293 years ago
You could try to connect the locking bar to a linkage so it draws back a bolt unlocking the door. Experiment!
samaw1293 years ago
hole punchers work well for the washers :)
tardis fan (author)  samaw1293 years ago
Never actually thought about using hole punchers for that. I might add it to the instructable.
haha yeah worked for me!
thing 23 years ago
Could you upload a video that shows how it works/a demonstration?
tardis fan (author)  thing 23 years ago
Most likely I will. Just have to find the time. . .
BuhBomb3 years ago
This reminds me of Furio Tigre's cardboard badge...
LiftAndLove3 years ago
you should make the lock mechanism smaller, so you can put stuff in the box.that's what im going to do.
tardis fan (author)  LiftAndLove3 years ago
Cool! Post some pics when you do.
ghostpotato3 years ago

i made this and only tool me about a hour and it works awesome.

might make a full case for it so you cant just look over the back and align them.
if i make that i might post some pictures. O and also knex rods are a good substitute if you don't want to use up pencils

p.s. be careful when hot gluing i got a nasty burn in my left pointer so now it hurts to type. lol why am i making this comment so long then??

this is truly ingenious and im giving a 5* for sure

my finger hurts :(
i was hot gluing once, and I was kicked in the head. it burned me);
oops in second line i made a mistake i meant only took me an hour not tool me an hour srry
tardis fan (author)  ghostpotato3 years ago
I'd be interested to see how the covered lock turns out.

Hot glue burns are nasty, aren't they? I got one while making the base and had to take the picture as fast as possible!
heathbar643 years ago
Very funny thing. I made one very similar to this a few month ago. My daughter had her first combination locker at school and I thought knowing how it worked would help her with getting it open.. too bad I didn't take a picture.
tardis fan (author)  heathbar643 years ago
This model is good at teaching about locks. My family has learned from it as well.
rimar20003 years ago
WOW, what a good work!
tardis fan (author)  rimar20003 years ago
Thank you!
tinker2343 years ago
wow great work
tardis fan (author)  tinker2343 years ago
Onyx Ibex3 years ago
I was just wondering why no one has posted an ible on this. It is very amusingly handy for all sorts of rediculousness. Well done!
tardis fan (author)  Onyx Ibex3 years ago
Thanks for the complement! Try your hand at making one!
kelseymh3 years ago
Now that is really awesome. Way back when I was teaching physical and information security courses, this would have been a brilliant take-home project for my students.
tardis fan (author)  kelseymh3 years ago
Thanks! If you make one, be sure to let me know!