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 :-)

Epilog Contest 8

Participated in the
Epilog Contest 8