The trebuchet is a medieval invention originally designed to lay siege to fortresses and castles. The largest of them could hurl immense stones hundreds of yards. Now you can have one to play with in your own home. The whole device stands about foot tall when unloaded and flings various things ten feet or more. Moreover, this is a nice introductory woodworking project that you can do with mostly basic tools. Make sure to check all of the images. A lot of the details are in the notes there.

Step 1: Materials and Tools

3/8" Hardwood Square
1/8" Hardwood Dowel
3/16" Metal Rod
Jumbo Craft Sticks
Wood Glue
Heavy Stuff as a Counterweight

Miter Box
Sharp Knife and/or Chisel(s)
Drill with 1/8" and 3/16" Drill bits

You can really make this project out of just about any type of wood. I chose poplar because it's cheap and sturdy. Most big hardware stores will also have oak and occasionally maple. The design is stout enough that you could make it out of something softer like basswood. In fact, it's probably not a bad idea if you don't have a sharp narrow chisel and you're going to be carving the joints with a knife. These measurements call for just a little over six feet of it. Most 3/8" square is sold in three foot pieces. You might get away with just two if you adjusted the size of a couple of parts, but you'll almost certainly have to recut a couple of pieces so you might as well just get three sticks.

<p>Thx im building this but its still pretty G A Y</p>
<p>Been making this for a STEM class that I volunteer with. They're having a blast.</p>
<p>Hi Is it possible to have the measurements in metric?</p>
For any guys that do shotgun reloading, mix bird shot with melted wax for the weight. You can then make the weight whatever shape and size you want, without worrying about melted lead fumes, since wax melts at a much lower temperature. Anybody that's ever made wax shotgun slugs knows what I'm talking about
could you give me the sizes of wood i would need to make the trebuchet in double the size. thanks <br>
<p>Multiply x 2. 3/8 x 2 = 3/4.</p>
wow this comment stream is the most epic and longest i have ever seen.
Thanks for the materials &amp; sizes. To speed things up and simplify it a little I took the side braces off. It still works ok: the uprights are pretty stable, though not as solid as they would be with that third outside brace.
My son and I just finished building a trebuchet base in your design. It came out quite well. We made some modifications; We doubled the scale. I was able to make a sling pouch out of denim that released properly. I added a catch to the throwing arm, so I can be cocked, loaded, and finally released by pulling the catch. A bucket of pennies provides the counterweight, although I think we're going to look for an aesthetically pleasing rock. <br>It took two days to complete, with my son doing much of the cutting, drilling and gluing. <br>Thank you for writing such a clear instructable. The joinery was a classy touch too! <br> <br>We're going to build a really big one outside next!
WARNING!!! nobody seems to have mentioned that TIRE WEIGHTS contain CADMIUM to harden them. CADMIUM vapor released by melting tire weights is far more dangerous to life than plain lead fumes. I nkow of at least two cases of near-fatal heavy metal poisoning of mountain man types casting flintlock balls from tire weights!!! Me, i used pennies for me weight, easy to fine-tune the range by adding or subtracting a handfull.
yes but penny fumes also release zinc oxide
I have melted tire weights in order to cast bullets for more than thirty years. Provided you do it in a well ventilated area there is no danger involved. Tin and antimony are used to harden lead in wheel weights. Cadmium is mostly used for battery plates WHICH SHOULD NEVER BE USED and for cable sheaths.
You could also use dead batteries for weights.
or a bunch of nuts. the kind that go on bolts, that is.
I had alot of fun making this. my daughter asked me to make a catapult but thought better of it and this was perfect. got wondering what else i can make with this extra wood i bought before i found this sight. Good work on the instrutions
Great Instructable, I love the joinery techniques. I am building one right now. (the glue is drying) One Important thing to be careful of: Lead is a chemical known to the State of California to cause cancer and birth defects or other reproductive harm. Melting lead creates lead fumes which are also toxic. Be Careful For my weight I took a fishing weight (unfortunately lead) and wrapped it with a lead sheet and hammered it together. I plan to encase it in Plasti-Dip when it is finished.
You wuss, lead was in paint and gasoline for ages and it didn't do any harm to W when he ate it and drank it...wait a minute...:) But really, I melted tire weights to make bullets and cast miniatures lots of times, as long as you don't get it on your skin (youch melted lead!) or wash your hands regularly and wear a mask while you're melting it, you'll be fine. Most of the damage is done when a child is exposed to it...If you're 18, your brain is almost finished, alcohol will do more damage..
My warning also extended to children (I am 15). I'm sure there are many users under 18 on this site who would be fascinated to create this, and be unaware of the dangers lead poses.
try tin weights
i used a block of steel i got at the local scrap yard
The plasticote idea is brilliant, though, it keeps the lead from smearing all over the place.. My 8 year old knows that lead is dangerous, she reads about it on warning stickers all the time. She also learned about mercury poisoning by reading about it, but she's smarter than the average 15 year old... If you're old enough to operate a hotplate without supervision, you should have learned by then what's poisonous and what's safe. It's been proven that lead weights and lead bird shot are harmless to the environment. Most of the lead poisoning in nature comes from unregulated dumping or landfills that were grandfathered in before they had such stringent requirements about runoff. The lead from the runoffs (from old paint chips) contaminates the ground water and poisons the animals. If a water fowl ingests a lead sinker or a piece of lead shot, it just passes through. If they survive a shot, their bodies grow a cyst around the shot with no harm. Even today, most doctors keep the bullets in their victims because it will cause more harm to remove them. But lighten up, Francis, you're too young to be such a stick in the mud. :) Girls won't like a guy that acts all tight, I know from experience. :(
<a rel="nofollow" href="http://en.wikipedia.org/wiki/Lead_poisoning">http://en.wikipedia.org/wiki/Lead_poisoning</a><br/><br/><em>The symptoms of chronic lead poisoning include neurological problems, such as permanent and temporary reduced cognitive abilities, or nausea, abdominal pain, irritability, insomnia, metal taste in the mouth, excess lethargy or hyperactivity, chest pain, headache and, in extreme cases, seizures, comas, and death. There are also associated gastrointestinal problems, such as constipation, diarrhea, vomiting, poor appetite, weight loss, which are common in acute poisoning. Other associated effects are anemia, kidney problems, and reproductive problems. It has been shown to cause permanently reduced cognitive capacity (intelligence) in children, with apparently no lower threshold to the dose-response relationship (unlike e.g. mercury.)</em><br/><br/>There's a lot that can go wrong besides brain damage. Although I do notice a strange similarity in the symptoms of lead poisoning and a hangover. :)<br/>
ya it does
wat if im clumsy, throw up sometimes, have sore abs, like after a workout or something, get mad for no reason, can't sleep sometimes, sometimes get a weird taste in my mouth, somedays be lazy, some over active, have slight pains in my chest on occasion, get headaches, and have a chance of seizures, comas, or death. What if i get constipated sometimes, every once in a while get diarrhea, am a picky eater, lose weight if i work out, have a slight lack of iron in my body (one cause of anemia), get a kidney stone, and have a chance to be infertile, or stupid.... that seems like a pretty normal human to me, lol
The way you said,"as long as you don't get it on your skin (youch melted lead!) or wash your hands regularly and wear a mask while you're melting it, you'll be fine." this makes it seem like" As long as you don't wash your hands, don't wear a mask while melting it, and if you don't get it on you skin you'll be harmed. I think i may just be making this up. But the 18 part is true. It only takes 10 micrograms of lead to cause permanent damage in a developing child. But once puberty is over it's much harder to get it. Considering the entire roman society was based around lead cups and plates and lead based make up, i think we'll be fine.
I got all sidetracked, the dude is talking about sealing lead tire weights in a tin can that will never see the light of day again. As long as he washes his hands after dealing with them, he's good to go. People make such big, dramatic deal over nothing. To quote Paul Newman,"Hell, the fall will kill you!" Lead is known the world over to cause problems if ingested. My Christmas lights have the warning because the Chinese probably used lead paint, just like any other third world country that figures their populace will probably die of some crazy disease long before they see the effects of lead poisoning. I'll probably die of mercury poisoning from corn syrup before I get lead poisoning, and I smelt tire weights and vaporize lead and other chemicals in the process. I take precautions, but the only way an intact tire weight will kill you is if someone shoots it at you in a bullet or a car careens into you from out of balance tires. Who was the genius that invented lead water pipes? Used lead solder to seal cans? I read that the oil industry introduced lead to gas to improve it's combustion because they had to meet smog standards for pollution control. That's irony at it's best.
i was just kidding around =0<br/>
Because I was worried about children potentially playing with the trebuchet I constructed (using this excellent tutorial, BTW), I ended up encasing my lead counterweight. I didn't have anything like Plasti-Dip on hand. Instead, I took an old steel padlock and placed it in the bottom half of a small tomato paste can. My PiC (Partner in Crime) and I placed lead fishing weights in the spaces around the lock and melted them with a propane torch (adding more weights as needed). I then cut and folded in the edges of the can, and melted wax over the remaining space above the lead. So the whole set up is sealed in steel can and wax, with the loop of the lock sticking out the top. The only issue that remains is that the folded can edges are a bit sharper than I'd have liked. I think that having some sort of plastic or rubber sealing material is ideal, but if I make another trebuchet, I'll be going back to the Bowl of Abandoned Locks as well.
You could probably put tape over the sharp edges of the folded down can to prevent cuts.
Fishing weights ('sinkers') can be found that are made of steel or tin - lead is forbidden in NH waters. FWIW, a scrap padlock (you lost the keys or forgot the combination) should be fine. Folks with some enough space could simply fill a milk jug with rocks and sand and water. Some older men used to collect nuts and bolts... galvanized steel piping could work, Plaster of paris....
You could have a box at the counterweight point, and fill it with whatever heavy was available. Rocks, nails, metal scrap or whatever. I found that you can find tire weights in the gutters along streets quite often.
Good call on the tire weights, all this time I knew they had a use.
and i think tin has a lower melting point so it should be easier to melt it
<strong>Just buildt one from your design.&nbsp; Few deviations......worked great.&nbsp; Used plasti dip spray on to coat the lead and brass rod for the arm shaft.<br> <br> Thks, my son really enjoys it.</strong><br> <br>
There are a lot of things you left out of your materials list that you used. To make things easier for us trebuchet-builder-people, why don't you just make a big list of<strong> all </strong>the stuff you used. Make&nbsp;your instructions more organized&nbsp;more organized.
what's the width of that metal rod?
it looks 3 inches to me they bigger than the lower arms which are 2.25" and smaller than part f
how long did this take to make
An old rule of thumb say that Free Weight Trebs FWT throw farther and Fixed Weight Trebs FXT are more accurate. In small scale is is probably irrelevant. Me I prefer fixed weight because the treb rolling back and forth after the hurl in response to the swing of the weight makes for a nice visual follow-thru. Trebs can be fine-tuned in several ways. As I said in my previous comment you can change the weight, you can also change the missile weight, the length of the sling, and the point of sling release. Also rather than using a sling (small scale slings are very difficult to tune) missiles with a loop attached to them are easy to make and tune by using a boy-scout variable knot to make the loop. A friend made a treb that threw tennis balls with a line and loop attached, his dogs retrieved the balls and the rope let her avoid dog-slobber.
Just finished mine, outfitted it with about a 1 lb zinc ball and a leather sling. This beast will launch a penny 15 feet or more, pegged my boss in the forehead with it!
hahaha! lol! He didn't fire you , didn't he?
Na, he was laughing too hard to think about that.
your boss is awesome
I am doing this for a project in school, I found this site and then found this instructable, it is so simple and easy. Of course i am creating it virtually but still ill probably actually make it.
I'd like to builde one!
I'm currently making a 2/3 scale model of yours out of popsicle sticks, it'll probably be done later this day!
For those who are curious as to how I am doing this, I am simply layering popsicle sticks together using gorrilla glue. 4 is a good number.
hey i think this instructable is awesome. i have always wanted a trebuchet. i have just two questions how does it hold the projectile, and how does it release the projectile.
The projectile is held in a sling that is attached to the end of the arm. It is fastened on one end, and at the other end, you have a loop on the end of the sling going over a small post (like a nail), that holds it until centrifugal force from the arm movement pulls it off.
awesome project almost fished with one I am building very very well build A+++++!!!!!

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