Picture of How to Build a Catapult
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There are already a few large-scale Trebuchet Instructables out there, but for the low-tech medieval enthusiasts, here is the first large-scale catapult Instructable!

This was constructed during my internship @ Instructables this past summer, with
DerangedMoose7, Tetranitrate, and noahw

Oh, and if you were wondering... Yes, "Project X" is finally here.

Camera work done by [www.instructables.com/member/noahw noahw]
Video editing done by [www.instructables.com/member/bofthem bofthem]

Step 1: Acquire Materials

Picture of Acquire Materials
You're going to need:
  • 9 - 8' two-by-four's
  • 1 - 12' four-by-four
  • 3 - 8' four-by-four
  • 50' of surgical tubing
  • Fiberglass windsurfing pole or a large section of steel pipe (Fiberglass pole preferred)
  • 20' thick nylon rope
  • 1- 4 ft section of 4" diameter ABS pipe
  • 1 -4 ft section of 2.5" diameter ABS pipe
  • 2 - 4"-2.5" step down ABS adapter
  • T-adapter for ABS pipe
  • ABS cement
  • 2" X 4' aluminum pipe
  • "S" hook
  • "U" bolts and nuts
  • Large Eye bolts
  • 12 - 6" lag bolts
  • 3 - 5" carriage bolts, nuts, and washers
  • Assorted deck screws (at least 3" long)

  • Chop Saw
  • Reciprocating saw
  • Drill Press
  • Assorted Drill Bits (including large hole-saw or adjustable spade bit)
  • Drill
  • Wrenches
  • Welder (if using steel pole)
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Would this be good for pumkin Chunkin :/

Yes, yes it would...

1300rpm5 months ago
Gonna fire stuff over trees, people have no idea what's happening XD this is incredible, by the way
emilooooooo9 months ago

Did this catapult launch an object more than approximately 100 yards?

T3h_Muffinator (author)  emilooooooo9 months ago
booooom1 year ago


nerd123 years ago
the actual name for this is an "onager". it was used by the Romans and call so because when it finer it jumped like a kicking donkey hence the name. the name was a donkey in old tongue. it is classified as a torsion powered siege engine
jobard4 years ago
This is more like a giant mouse trap with a stopper
Tin.Man4 years ago
Since it seems you don't reply to any messages though I hope you do. I am wondering if you or anyone else knows what to do with the firing mechanism if using fibreglass pipe. Because if a hook is screwed in it, it seems like it would probably break out of it under the strain. Anyone have any ideas what i could do for the firing mechanism? Thanks!
d4rksaber4 years ago
Is it legal? :D
legal is never fun
how much did this cost
Kruegem4 years ago
not a trebuchet
this is not a trebuchet!!!!!!!!
I guess its a type of Onager Catapult
Whats an Onager Catapult?
jocofee Fashim5 years ago
an onager is a catapult that uses tension to launch a projectile, as opposed to a trebuchet that uses counterweights to launch them.
It uses a twisted rope for power.
thats what i was thinking too.
jose1ca daninja5 years ago
me too!
You are correct it is a catapult trebuchets have a counter weight
frodobot5 years ago
Do you know at what speed the projectile travelled at approx.?
0087adam6 years ago
The Old Trebuchets used ropes as a twist thingy i forget what they are called.
muttyfutty5 years ago
I could be wrong, but dont mythbusters shout 'fire in the hole' 3 times? (to the left, to the right, and down the center)
Kiernan6 years ago
I am gonna launch a bunch of airsoft BBs with this thing at my next airsoft game. :D
0087adam6 years ago
did you consider using timber-framing joints and all 4x4. I got some old pallets to cut up and have tons of 4x4 so i think im going to try that.
#9EJV6 years ago
how much it cost to buy all the stuff
axiesdad7 years ago
Good instructable, both clear and fun. At the risk of transgressing the "be nice" policy, I have to say one thing. Getting a tool from the hardware store and using it once then returning it is not "beating the system.;" It is stealing. Please do not encourage the people who read your instructable to become thieves.
dude stealing is against the law the is perfectly legit you use it then turn around a return most places probably wont take it back but for those that do you pretty much did just beat the system
You're right. It's not stealing at all, he payed for it didn't he? He used it for it's purpose and took it back, that is not stealing. That's just beating the system.
So if I steal your car it's OK as long as I bring it back?
no if you pay for a car and bring it back
Its not beating the system, its taking the systems lunch money and laughing at it, the hell with the system, go return your tools after using them once!!
cody316 cody3166 years ago
its the right thing to do if u want more room in the shed!
ha ha
it's not "beating the system"
it's just returning it... if they let you return it, then it's part of their "system", sooo....
Tools wear out. When you return a tool after using it , it is worth less than when you bought it. You have stolen that difference in value, either from the hardware store owner (if he cannot resell the tool for its full cost) or from the purchaser (if he can.) If you don't want to be called a thief, don't steal -- or else steal millions, then they will call you a banking executive.
its the morals of it, it may not technically be stealing but it is the same
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