Introduction: The Office Supplies Trebuchet

Picture of The Office Supplies Trebuchet

Bored at work? Build your own 3" trebuchet out of paperclips and throw balls of blu-tac up to an amazing 4 feet. WOW!!
Please excuse the number of steps. It is really easy and can be made within an hour and from bits lying around the office, hence very cheaply.

Step 1: The Tools and Materials List

Picture of The Tools and Materials List

You will need:

1 pair of pliers (needle nose would be best, where available)
1 pair of scissors (yay for scissors)
8 paperclips
thin string/thread
Corrugated card (approx 6"X6")
Ballast (I used a bunch of batteries from our recycling box)
Rubber band

Step 2: Straightening the Paperclips

Picture of Straightening the Paperclips

Use the pliers to make the paperclips as straight as possible.

Step 3: Now Shape Them

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At the very end of four of the paperclips, make an eyelet big enough to insert an ex paperclip through (but not much bigger).

At the other end, make a dog leg. Try to make it on the same plane/axis as the eyelet.

EDIT: Ignore the dogleg. Instead bend approximately 1/2" of the non-eyeleted end at right angles (90 degrees) to the eyelet. All will become clear very soon.

Step 4: The Axle

Picture of The Axle

Next, shape the axle. Make it so that the distance between the hooked ends is about 2". It should be wider than your intended ballast. The V shape (U shape in this case. Needlenose pliers are best for this sort of thing) must be central on the axle.

Step 5: The Arm

Picture of The Arm

Make an loop in another paperclip about 1/2" from the end. At the same end make another eyelet.
Make a small hook at the other end.

Step 6: The Trigger

Picture of The Trigger

A little hard to describe. Just look at the picture. The bump on the left is to pull. The loop on the right is there to catch the little hook on the arm.

EDIT: See the adjustment I made to the firing mechanism in the final step. It works so much better.

Step 7: The Components

Picture of The Components

Here's what you should have so far.

Step 8: Assembling the Parts

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Take the axle and insert it through the loop in the arm (not the eyelet) so that it sits in the V. I wrapped Cellotape around the axle either side of the V just to give it some thickness (so it doesn't slide all over the place).

Step 9: The Base

Picture of The Base

Mark the base with a center line. The two lines are about 3" apart and the little Xs on those lines are also 3" apart.

EDIT: Cut the card to 3"X6" with the grain of the corrugation laying along the 3" distance. Mark the center line along the 6" distance and two lines 3" apart at right angles to the center line.

Step 10: The Base (cont)

Picture of The Base (cont)

Poke the dog leg ends of the supports into the four Xs so that the ends are between the layers of the corrugated card. If you made the dog legs at the right angle (not a right angle though), they should sit as nicely as mine. Maybe making the dog legs at this stage would be better?

EDIT: The new style supports from step 3 don't get pushed through the card as shown here. Instead, insert them into the raw edge of the card. You don't have to worry about the angles of the doglegs being incorrect, and these will be much easier to secure in position with Cellotape.

Step 11: Mounting the Axle

Picture of Mounting the Axle

This is a little bit fiddly but poke the hook ends of the axle through the eyelets in the supports, then bend the hooks down with the pliers.

After that, tape between the legs to make an A-frame and then from there to the sides of the base to prevent side to side motion

Step 12: Mounting the Trigger

Picture of Mounting the Trigger

Push the end of the trigger into the layers of card where the center line intersects the support line(the side that the arm hook is on).
The other end of the trigger needs to run in a slit so that it can slide back and forth. Don't make the slit too long or else you risk the trigger being pulled out.

EDIT: See the last step for attaching the improved version.

Step 13: The Ballast

Picture of The Ballast

Make a little hook and tape to one of the batteries.

Use the rubber band to attach a whole bunch more batteries around the one with the hook

When they're all assembled and hooked on the arm make sure the ballast is not touching the base.

Step 14: The Ammo

Picture of The Ammo

Take the string, put a loop in it and push the free ends into a pea sized lump of Blu-tac.

Wrap it around a couple of times and then smoosh the Blu-tac into a ball.

The extra string inside will allow you some length experimentation to gain maximum distance when firing. A good length is about two thirds the distance from the hook to the axle along the arm.

Step 15: Finishing Up

Picture of Finishing Up

Hook the ammo over the arm, pull the arm down and trap the hook with the trigger.
Position the ammo on the center line and at full extention of the string.

Aim and fire by pulling the loop on the trigger towards you. CAUTION!! The arm moves fast and has a sharp little hook on it. Don't use near your eyes. Also, this isn't the most acurate piece of equipment ever designed. Just because you're aiming it forward doesn't mean the Blu-tac is going that direction. Make this at your own risk. And make sure your laces are tied. And no running with scissors.

Step 16: Extras

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I've already mentioned changing the string length to change the way the ammo flies. Also changing the weight of Blu-tac, changing the weight of ballast and altering the hook angle will affect the flight path of your ammo

Step 17: Release Pin Modification

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I think a few of you have already worked this out, but never mentioned it. Well, I found a more reliable way of launching the ammo a while back when I was building a new one but have only just got around to documenting it.

I rotated the release pin 90 degrees so that now instead of drawing back like a bolt, it's hinged and rolls back off the hook of the arm. You launch by pulling back on the lever.

Very simple and you can use the original pin, though it may need some reshaping. Just make sure that it's placed far enough foward to release the hook and that it doesn't snag the ammo on it's journey past.


ProtectTheAlphaWolf (author)2016-04-21

ooh I so want this!

blakesusername (author)2012-06-10

Cool, I made one of these at work, I used a D cell battery for the counterweight, and for a projectile I used a penny taped to a short piece of string, this string has a loop at the end and attaches to a hook on the end of the trebuchet arm. It can launch the penny about 10 feet with pretty good accuracy I was actually able to launch the penny into a cup. :) yes my job is very boring.

vincent7520 (author)2012-06-10

No video showing how to target you boss( left eye, and the face he makes when he gets it's on his sandwich at lunch time ???

Thank for the inst' anyway !…


123456789115 (author)2008-12-18

you took this idea from another website you fail!!

Actually quite interested where you saw this. If it was the Discovery site, that was me. Anywhere else and they copied me.

No I didn't.

Redmonkey17 (author)2011-12-05

P.S. it makes it much more stable.

Redmonkey17 (author)2011-12-05

Instead of taping the two a-frame posts together, add an ex-paperclip support to make a tripod

Mustapha69 (author)2011-11-18

model magic also works

Eviil~~PikmiN__{7} (author)2010-11-23

of course we all have PLIERS laying around the office

Why wouldn't you?

I carry at least a Leatherman Wave and a small swiss army knife with me always? He's not prepared?

Well, "someone" is not going to survive the zombie apocalypse. :)


I do...

:D its funny because its sarcatistly true

you could use the handle of the scisors as pliers

Alex Palfreman-Brown (author)2008-09-17

20ft?!? That's a great range. I should really retrieve mine from it's box and start an office war.

War of the classrooms >=P.

ductapeman (author)monkeyshoe102011-04-28

one time my teacher braged that he was better than all of the school so we had a "teacher vs. kid" day

bubba j (author)monkeyshoe102009-06-02

you idea got me sent to the princabal monkeyshoe10but ithink it was woth it

monkeyshoe10 (author)bubba j2009-06-02

Well if its worth it =P

bubba j (author)monkeyshoe102009-06-11

my problem was miss tattletale was in fromt of my target and i nailed her in the forehead (or was it her butt i can't tell the differance)

Dumchicken (author)bubba j2011-01-28

thats mean and insulting.


I made a cross bow out of pencils, a alligator clip, rubber bands, and duct tape in 8th grade. It could shoot a gold fish like 20 feet and a half a pencil about 30+! It was good cause it was pretty small and I could make goldfish explode on the bus drivers windshield teehee.

 goldfish! ur mean!

he's talking about the cheesy craker not an actual fish

Tommyhzy (author)crazyscott852009-02-16

Every exploded goldfish means one KARMA point taken away from you, lose your 100 points and something very bad will happen... Save your KARMA, don't launch goldfish from crossbows!

randomguy96 (author)Tommyhzy2009-05-08

Is that supposed to be a reference to Fallout 3? If it was that was a good one.

muttyfutty (author)randomguy962009-11-28

Isn't the fallout limit -1000? (Very Evil)
BTW, love Fallout 3!

crazyscott85 (author)Tommyhzy2009-02-21

uhh yeah gold fish are a type of food.... Real gold fish would be hard to put in the cross bow and they would move too much. Good idea though

bubba j (author)crazyscott852009-06-02

no they don't flop but they splat (my bro still has not forgivin me

bubba j (author)crazyscott852009-06-02

ive done that 4 years with pennies and never been caught ( i dont know what i did but i can hit the windshield siting in the back with my sertroid mini crossbow)

 i  finally made mine working good all i need is ammo and i w)ill see you on the battle field (i didn't have batteries so i tied up some paperclips hoping to get better weights so i can use the paperclips an trebuchet supplies hey we could make a game out of paperclip men and make paperclip swords and bows to wage a full scale battle with infantry and archers and catapults it will be so cool!

Mitey Mites! (that's how it's spelt, i know right?) Put them in a playdough ball and THEN launch them. More bang for your buck

ductapeman (author)2011-04-28

dduuuude make a 1 paper tat u can fold up

the dudemaster (author)2011-04-17

this instructable would be 100% percent better if you added more measurements. i just grabbed eight paperclips out of my computer desk and got to work and my clips were to long so i had to guess my base measurements and the result wasn't pretty.

venom1539 (author)2011-04-05

and also, what size of batteries are those

venom1539 (author)2011-04-05

I've been trying to build a portable trebuchet so that i can bring it to school and shoot erasers during indoor recess but just having one is fine. Now i can shoot erasers at my friends when they come over.

steeler65 (author)2009-11-02

i wonder if it can be used with different sized paper clips becasue i cant ever find seven of the same paper clips

cut all of the paper clips to the size of the smallest one you have. unless it was ridiculously small... most pliers have a v-notch thing that allows you to cout wire so you can use that.

then cut the small paper clip to the size of the big one

Lol, how ridiculous.


No no, seriously, how can you cut a small thing to make it bigger? Maybe you misinterpreted my comment. Got any sarcasm left in you?


maybe... lol

Play nice people. (But I can cut a hole in a postcard that I can fit through. Maybe I'll Instructablise that one)

haha :D He probably mistook it as an offensive statement, but I don't want to take it further.

About This Instructable




Bio: Making things to entertain myself comes second to entertaining my offspring, but my mind is always working something out.
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