K'nex Lock and Key





Introduction: K'nex Lock and Key

About: A mechanical engineering major just looking to have some fun with K'Nex.

These instructions show how to make the K'nex lock and key created by you-tuber Richard Thiessen HERE and seen also by maxknex050 HERE. I give full credit of the design to Richard Thiessen but found it difficult to create the lock through the video and saw many requests for instructions so here they are. This lock style is called a mortise lock for those of you who were wondering. Now for some pros and cons.


Uses specific customizable key

Almost impossible to pick (adding an extension to the bottom left corner would make it completely impossible)

Very sturdy (you cant' just break the box open to unlock it)


It will occasionally jam after using an incorrect key or attempting to pick it (but it will jam in the locked position!)

If a part inside the box breaks you have to take the lock apart to fix it


Step 1: Making the Box

These are the outside edges and bottom of the box, follow the pictures and make the parts. If your confused read the notes. Most of the pictures are taken from the "back" of the box

Step 2: The "Levers"

These parts are called the levers and are the parts that allow (or don't allow) the rod to pass through. These parts are loose and are slid by the key. If you would like your key to be different these are the parts you should change or rearrange. After making the levers place them inn the box in the correct places, check the notes for help. Also in the last two pictures two green rods are missing but you should have already put them there. Ignore these missing pieces (they are marked by notes).

Step 3: The Top of the Box and the Bolt

The first pictures are to build the bolt then the top of the box. Two Y clips on the bolt are twisted the wrong way and are marked by notes. A later picture shows them the correct way. Follow the Pictures, check the notes (they are really helpful in this part)

Step 4: Key and Finish

Quickly build the key (or your specific key) and your finished! Slide the key into the opening depicted in the second picture, or watch the videos if you are still confused. Now build a safe or just spend hours trying to pick the lock. Ask questions if you need I check back regularly! And post any improvements or safes in the comments below!



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    This is very cool, I like it ;)

    Good job

    Good job on the lock, and better job on the instructions, they are very clear. I am subscribing too.

    The only way I can think of is to lengthen the entire lock including the bolt and then lengthen the size of the pieces of the key that move the bolt up and down.

    Ok thx Is there any way to make I come up farther( I'm making a huge safe and this is the lock. I need it to move just a little farther up

    A small piece of the bolt sticks out when it is down but when it is up you should be able to see most of the yellow connectors

    This is how far I got the bolt to move --------- is this right or can it move more ( if it is right than is there any way to mod it to get it to move more) :-)

    15, 11:26.jpg15, 11:26.jpg15, 11:26.jpg15, 11:26.jpg

    So I looked over the internals and I put the levers in the wrong position sorry about all the questions

    Even with the key built right the lock still does not seem to work. I really don't know what and how the lock works , what is supposed to happen ???

    It looks like I made the mistake . lol I built the key wrong

    Hmmm...the three pieces in the middle of the key are suppose to move the bolt. Try checking to see if the y clips on the bolt are turned the correct direction (opposite of the way I have them turned in the first couple of pictures). If that isn't the problem I can look over the instructions to see if I made any mistakes.

    What is the key supposed to do? The bolt does not come loose nor does any thing else . The only thing that seems to move is the tumblers ( the interchangeable plates that change the combo ). Do u have any suggestions? Thx great build