Introduction: Marble Shooting Mini Knex Catapult

Picture of 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

Picture of Pieces Needed

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

Step 2: Making the Base

Picture of Making the Base

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

Step 3: Making the Sides

Picture of Making the Sides

again just follow the pictures

Step 4: Making the Arm

Picture of Making the Arm

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

Step 5: Adding It Al Together

Picture of 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

Picture of 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

Picture of 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.


ch33sl3y made it! (author)2016-08-09

ha, fast easy build and great fun. just adjusted the launch end slightly to take paper balls so the 3 year old can play with it. thank you:)

un864 (author)2015-03-08

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

David N (author)2014-03-02


Element Force (author)2012-04-11

5 star *****

jaberwaukee (author)2012-01-12

i give 10/10

jaberwaukee (author)2012-01-12

this thing works great

dglover15 (author)2011-01-25

add a spoon on the top and more rubber bands! it flys!

me (author)2010-12-26

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

TheAwesomestDude (author)2010-12-26

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!

doodleninja (author)2010-12-11

best knex one i ever tried !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

anihilator (author)2010-12-01

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 :

codybraun1996 (author)2010-08-17

thats cool im building it right now

dursa (author)2010-08-06

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

xbox1kid (author)2010-03-03

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

splodies (author)2010-01-24

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

jamesjames (author)2010-01-11

its a speaker

applejuice1998 (author)2009-11-28

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

me (author)applejuice19982009-11-29

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

applejuice1998 (author)me2009-11-30

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

mosesscopazzi (author)2009-09-19

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 :-)

Ry4n (author)2009-06-27

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

blazedude22 (author)2009-05-19

love it srry i took ur idea for a school prodgect but cool

me (author)blazedude222009-05-20

that doesn't matter, I'm glad you like it

An Villain (author)2009-04-10

you stole my idea 3rd street saints i did the exact same thing

bookmark (author)2009-04-10

interesting, but how do you load the marble? it would be good if you could develop a bucket for the marble

me (author)bookmark2009-04-10

the marble can rest on the two green pegs at the end of the arm

stormz76 (author)2009-04-08

good catapult i put a livestrong band on i instead of the rubberbands. i also made a larger one instead of blue rods i used grey ones it can easily shoot a marble a good 50 ft plus

3rd street saints (author)2009-04-06

this is a very good little catapult something i found handy was if you put a yellow pice on the middle purple part it stops the arm from getting stuck

TheMoonMaster (author)2008-05-25

All you hace to do is add a white rod with ywo grey connectors facing opposite dirrections. Clip it onto the very front socket of the snowflake. Also add these yellow connectors and rods to balence it.

me (author)TheMoonMaster2008-05-26

works great, thanks for the modification =)

CameronSS (author)2008-05-24

I'm not a big fan of the K'Nex Instructables on here, but this deserves special mention for being well done. You have nice, clear pictures without distracting backgrounds, a clear parts list, and images that clearly outline every step. More people who post ridiculous K'Nex guns should take note of this Instructable. Well done!

s0lekill3r (author)CameronSS2008-05-24

Wow, talk about a stereotype. There are some very well made guns that have clear instructions here on instructables. All you have to do is sort through the other bad guns to find them.

CameronSS (author)s0lekill3r2008-05-24

Thank you so much for taking a positive comment toward me and skewing it around to turn it into a negative comment! I just love it when people accuse me of stereotyping, even when I am stating a fact that you agreed with!

s0lekill3r (author)CameronSS2008-05-25

Yes, I agreed that this instructable is good. I don't however like that you shot down all of the other k'nex guns out there. Maybe next time you should specify who and what you're talking about.

CameronSS (author)s0lekill3r2008-05-25

Where did I shoot down all of the K'Nex guns? An annoyingly large percentage of K'Nex guns have horrible iBles, although it has gotten better. This comment string is ridiculous and inane, and I will no longer reply to it.

s0lekill3r (author)CameronSS2008-05-26

"people who post ridiculous K'Nex guns" Although this can be taken two ways and I may have taken it the wrong way, it can be offensive. Basically saying that my hobby is ridiculous and is not needed.

TheMoonMaster (author)2008-05-25

Great Instructable! Its easy, fun and really useful. The pictures were great and the instructions were very clear. I made a few minor changes so that it can be more powerful with out the arm jamming but other then that its great!

me (author)TheMoonMaster2008-05-25

well please share them with us, because I actually ran into the same problem, if you put on to much rubberbands it jams

dinky (author)2008-05-25


me (author)2008-05-24

thanks for all the great comments

dsman195276 (author)2008-05-24

good, nice, well done, and original = 5 stars!!!

PineapplebobTheGreat (author)2008-05-24

Awesome. 5 stars

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