Marble Shooting Mini Knex Catapult




Intro: Marble Shooting Mini Knex Catapult

I know there are already a few knex catapults here on Instructables and mine might not be that much different from them, but I still wanted to add it an see what you think of it.
I do hope you don't mind if I make any spelling or grammatical mistakes, because I'm from the Netherlands.
Now continue on to the first step for a list of the parts you will need.

Step 1: Pieces Needed

here is a photo with a list of pieces needed to build this device

Step 2: Making the Base

it doesn't need any explaining, just follow the pictures

Step 3: Making the Sides

again just follow the pictures

Step 4: Making the Arm

note that in the second picture the three parts are combined using three white rods

Step 5: Adding It Al Together

slide the yellow rod through the hole in the yellow connectors and add the spacers, note the two grey clips at each side of the yellow rod

Step 6: Adding the Rubberbands

attach the rubberbands on the front of the arm with a white rod. then pull them underneath the arm and attach them at the back of the catapult by putting them around the white rod in the back.

Step 7: Finished

congratulations you finished the catapult. it wasn't that hard, was it? now there is only one thing left to do, telling me what you think of it by leaving a comment. I hope you like it and I hope to make another instructable soon about a marble ballista made from knex.



  • Furniture Contest 2018

    Furniture Contest 2018
  • Tiny Home Contest

    Tiny Home Contest
  • Halloween Contest 2018

    Halloween Contest 2018

41 Discussions


3 years ago

I made a minature version of this using micro parts. Here it is next to the original


7 years ago on Introduction

wow it's been a while since I built it and there are still people commenting, thnx I guess

I like the way you designed the catapult, i only have 1 sugustion, put a guard in front of the catapult so that it does not fall over.I had to do that or it would malfunction!


7 years ago on Step 6

i put a locking mecanism and it rocks ! you can go to youtube to see it (sorry for my poor english, I'm french)

link :


8 years ago on Step 6

instead of putting the inside white connecters i used reds on the outside


8 years ago on Step 7

pretty cool ;p  fun to fire sneak attacks at unsuspecting siblings
7/10 nice job


8 years ago on Introduction

i put like 7 ruber bands on it and can now shoot a marble across my living room. i love it

nice job on this catapolt! it's pretty damn stong, ive dropped it several time's ( on accident ) ive shot some pretty big object's from it, and it does shoot marble's pretty far/hard it's solid build, and picture's and tutorial are perfect!
very good job on this instructable :)
btw how did you come up with this idea?
were you kinda bored and dicided to slap togeather a bunch of knex, or did you see a disign in a book or something like that?:P

2 replies

Reply 8 years ago on Introduction

Thanks a bunch for all the positive feedback, I'm really glad you like it
and yeah I just got bored and slapped together some knex to make this:P
it's been a while though since I made it


Reply 8 years ago on Introduction

lol you are very welcome! it's a solid design.
when people are bored, they can come up with some wicked design's ;)
lol good job tho :P


9 years ago on Step 6

when you make it really powerful and mod it (like me) the throwing arm gets stuck but i found if you put a yellow axle to stop the arm from swinging down to far it eliminates that problem :-)


9 years ago on Step 7

ermm good but when you fire it the bottom of the arm gets stuck between the 2 snowflakes