K'nex Ball Machine Lift Instructions: Full Automatical Giant Ball Catapult

Introduction: K'nex Ball Machine Lift Instructions: Full Automatical Giant Ball Catapult

About: I'm french, I live in a house, I love build stuffs with K'nex and Arduino, I have a YouTube chanel, and i enoy building some devices for Halloween

This is my new lift, the Giant K'nex Ball Catapult, in my room it shot 4 meters away (because my room is too small), but I think it can about 10 meters away maybe, it only countains a motor, it's fully automatic, the arm is tracted by a nylon cable, but the shot is very hard to regulate, because the catapult shot creates a role-back, and the elastics extend.

I've build a second version, it's economize pieces, and I've done some improvement.

And now, let's get started !

Step 1: Part List and Caution

Before starting to build the catapult please read it atentivly:

WARNING! The nylon cable can cut very badly when the catapult is shooting! (it can cut plastic !)

In case of accident I decline any responsibility !

PART LIST:(for the basket version with the lift)


-grey: 79

-red: 121

-yellow: 172

-blue: 364

-white: 164

-green: 210


-blue 3d connectors: 151

-purple 3d connectors: 242

-white: 33

-yellow: 137

-green: 24

-red: 111

-orange: 67

-light grey: 12

-dark grey: 72


-medium yellow gear: 3

-medium red gear: 7

-small blue gear: 3

-lock clips: 20

-pink straight rod: 5

-grey spacers: 51

-blue spacers: 56

-green motor: 1

-red double compartment motor: 1

-Y clips: 15

-nylon cable (10 kg chargeable) : 1 meters (3 feets)

-chain link: 65

-black hinge connector: 2

-blue hinge connector: 2

-cushion (35 on 35 cm): 1

-big brown scotch: 1

-rubber bands (120 on 1,8mm): 13

-rubber bands (60 on 1mm): 2

Step 2: Frame of the Catapult (part 1)

Step 3: Frame of the Catapult (part 2)

Step 4: Assemble the Two Parts of the Frame

Step 5: The Rearming Mechanism (part 1)

Step 6: The Rearming Mechanism (part 2)

Step 7: The Rerming Mechanism (part 3)

In this step you will need a teflon roll.

Step 8: The Rearming Mechanism (part 4)

Step 9: The Firing Mechanism (part 1)

build the first part of the firing mechanism

Step 10: The Firing Mechanism (part 2)

Step 11: The Catapult Arm

build the arm of the catapult.

attach the catapult arm.

place the nylon cable.

adjuste the nylon cable.

Step 12: Placing the Elastics

Place the double-elastics.

And equilibrate them.

Step 13: The Anti-tangle System (optional)

This is an optional step.

But it can be useful.

Step 14: The Ball Dispenser Tower

Step 15: The Ball Dispenser (part 1)

Step 16: The Ball Dispenser (part 2)

Step 17: The Ball Dispenser (part 3)

Step 18: Assemble the Ball Dispenser Tower With the Catapult

Step 19: The Tower of the Basket

Step 20: The Basket (part 1)

Build the first part of the basket.

Step 21: The Basket (part 2)

Build the second part of the basket.

Step 22: The Basket (part 3)

Build the third part of the basket.

Step 23: The Basket (part 4)

Build the final part of the basket.

Step 24: Place the Catapult and the Basket Tower

Place the basket tower.

Place and attach with scotch strip the catapult.

Step 25: Well Done !

So, it's finally finished !

feel free to ask for help in the comment section :-)

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    9 Discussions


    3 years ago



    3 years ago

    Brilliant! Was hoping you were going to make instructions. Voted too!

    Mister Gears
    Mister Gears

    Reply 3 years ago

    thanks ^^


    3 years ago

    This is pretty cool. :D

    Mister Gears
    Mister Gears

    Reply 3 years ago

    thanks !

    Lexi Knex
    Lexi Knex

    3 years ago

    ah bon ? on m'a jamais averti de ne pas construire un knex pcq j'avais pas l'age xD. Comment cela pourrait il me blesser ? les doigts ?

    Mister Gears
    Mister Gears

    Reply 3 years ago

    ba le truc c'est que quand la catapulte tire, le fil de nylon se déroule tellement vite et violement que sa entaille les tiges de K'nex, alors apres si tu veux mettre tes doigts dedans, c'est toi qui voit.


    3 years ago

    Holy COW!!!! This is AMAZING!!!! Thanks for the instructions! I LOVE THIS! IT'S EPIC!!!

    Mister Gears
    Mister Gears

    Reply 3 years ago

    Thank you :-) !