InstructablesTV: Open a Can With a Knife





Introduction: InstructablesTV: Open a Can With a Knife

About: Tim Anderson is the author of the "Heirloom Technology" column in Make Magazine. He is co-founder of, manufacturers of "3D Printer" output devices. His detailed drawings of traditional Pacific...
This week on Instructables TV we open a can with a knife.
This is a very useful skill, because often there's no can opener to be found.
In fact, there were fifty years when cans HAD to be opened without a can opener.

W'pedia sez:
"The first tin cans, invented in 1810, were heavy-weight containers that required ingenuity to open, using knives, chisels or even rocks. Not until cans started using thinner metal about 50 years later were any dedicated openers developed."

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Step 1: Advanced Technique: Open Can With Ballpoint Pen

From my Yucatan Proa trip log:

A Bic ballpoint with the hard clear body as seen here is good for this.
Some pens are made of soft plastic that isn't as good. This old model is great. It survives salt water and all kinds of abuse. The ink doesn't run when it gets wet. I liked it better than an "astronaut" pen that failed on the same trip.

Open Can with Pen:
1: Using a corner of the pen's blunt end, score the can across top. This makes a big "X" in the top of the can.

2: Stab a hole in the middle of the top with ballpoint. This is easier than it sounds.
Now there's a hole in the middle of the X. A hole with four corners.

3: Enlarge the rips in the four corners. Push each corner along with the handle of the pen til it reaches the edge. Pry up each flap.

4: Eat contents with two sticks as chopsticks. Plan uses for the interesting metal thing you have left.



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    22 Discussions

    There should be a "DON'T TRY THIS AT HOME" warning at the beginning.

    The knife used must have been really blunt otherwise it would have ripped open the guy's palm.

    One of the first things parents teach their kids in the kitchen is never to cut towards yourself. Always cut away from your body.

    The video and advice is irresponsible. Kids might not know you are trying to be funny and actually try it.

    wow, this is actually how i open all my cans. Tim, you have a very neat technique, for some one who looks like a crazy man. very tidy can edges. Actually, you can open a can with butter knives. but you have to use a "psycho" stabbing motion, and you have to do it a bunch of times until you get one near the edge, then you can use a leaver action to tear a hole large enough to get the contents out.

    1 reply

    Im good I have a can opener on my pocket knife lol. Will remember both tricks for just in case uses.

    Or do as I do. Step1:make can sized hole Step2:put can in hole Step3: put a small amount of flash powder on top of can, add fuse Step4: light fuse and RUN!!!

    Glad to see it done. Does the knife blade material have an effect? Relatively soft stainless steel vs. good knife steel (1095?). (But Tim, what did your granddad say about eating with your knife???)

    2 replies

    You don't want to try this with a thin flexible blade or a jack knife that doesn't lock open. A little blood's not going to totally ruin your peas, but we want to keep it to a minimum. :)

    hey nice one! funny how technology can skew such obvious solutions.. started to panic when i realised i only had butter knives, but turns out the 1" serrated blade on my waiter's friend did the job. it was a bit of a mission, but im happy to say i didnt end up eating any shrapnel!

    I just found the new last words my victims are ever going to hear: YOU!!!! KNIFE!!! OPEN!!!

    1 reply

    how to open a can with a knife:
    step 1: find a can and a knife
    step 2: stab the top of the can in
    step 3: eat (_)


    11 years ago

    Woah! Sorta reminds me of Rick from the young ones.

    I love the energy. "CAN...KNIFE...OPEN!"

    Makes me miss my old P38 (Army issue can opener). I used that thing until it wore out and fell off my key ring. The first cans were actually more like wine bottles and were conceived in response to a prize offered by Napoleon Bonaparte as an safe alternative to feeding troops through pillaging. It was the British that started making them out of steel and it was considered an quite art to produce them one at a time. The first commercially available can openers, according to my book on Inventions, were offered free with cans of Bordon Evaporated Milk. They were the hook & claw type and had a red bake-light handle shaped like Elsie the cow.

    1 reply

    you can buy that at any army surplus place. I just bought 10, gonna try to make some crazy ninja/kitty claw gloves.