Blade Firing K'nex Knife





Introduction: Blade Firing K'nex Knife

This instructable is on how to make a knife which can fire its blade. Useful when you are down to a knife when your opponent still has a gun, you can lull them into a false sense of security muahahaha! It can also fire small pellets.

I am not going to say 'it is my first instructable so be nice' because i hate it when people say that, so feel free to say so if it is rubbish. However, i do not want people saying bad things about k'nex in general.



Step 1: Pieces Needed:

8 yellow 5-way connectors
4 red 3-way connectors
1 ball socket connector
1 light grey two-way connector
2 hand connectors
8 white rods
9 green rods
1 yellow rod
2 bendy orange/red rods the length of yellow rods
2 elastic bands

all knex colours are in the metallic colours.

pic 2: you will also need these three pieces.

Step 2: Make Frame

Make both of these identical pieces.

Step 3: Make Trigger, Ram, Ram Aligner and Side Support

pic 1: trigger

pic 2: ram

pic 3: ram aligner

pic 4: side support

Step 4: Make Blade and Pellet

pic 1: blade

pic 2: pellet

Step 5: Assemble the Knife

pic 1: take the frame pieces

pic 2: add the side support with a white rod

pic 3: add the other side of the frame

pic 4: insert a white rod through the hole indicated

pic 5: add frame aligner

pic 6: snap white rod on where indicated

pic 7: add trigger

pic 8: insert ram

pic 9:

Step 6: Adding Elastics

pic 1: where the ram elastic goes

pic 2: where the trigger elastic goes

Step 7: Loading and Firing

pic 1: the blade has to be this way up. push it in until the trigger makes a small clicking noise.

pic 2: the blade is now loaded

pic 3: the pellet must be this way up also

pic 4: the pellet is loaded

to fire press the trigger forwards

Step 8: Mods

to make it more powerful, you can lengthen the frame and lengthen and strengthen the ram.



    • Pocket-Sized Contest

      Pocket-Sized Contest
    • Paper Contest 2018

      Paper Contest 2018
    • Pro Tips Challenge

      Pro Tips Challenge

    We have a be nice policy.
    Please be positive and constructive.




    Give it a real blade and "BOOM" it's a completely illegal weapon that can get you arrested, potentially the first ever legitimate knex weapon. background info, any projectile weapon not classified as a gun or A.O.W. (any other weapon), both of which use gunpowder is completely illegal to own or fire.

    dude the knifegun is seriously EPIC! as for the super knex rifle thatguy was talking complete BS about, he is full of BS cuz my dads an engineer and he said that it would be impossible for a knex gun to do that without being reduced to rubble. any way im going to try and improve on this knife cuz i have too much time and nothin to do.

    epic but i can't get fotos on

    almost for got i will post photo soon

    I just made it omg!

    At first i could not fin the bendy pieces
    Then i did not have the ball joint thing, but i did make a sub for it a pulple/grey one way connector.

    Nice dude.I love blade warfare opposed to guns. they are just so much beter for killing zombies :)!

    this thing is freakin awsome!!!!!!!!!!!!!

    hey guys try my knife


    I love this! I made 2 and made them into one. Knife shotgun anybody?

    awesome! just like in black ops. 5 stars!