Trebuchet

[paaiyan]

I've been planning on building a trebuchet for a while now, but I need some 4x4 posts. Anyone know about how much they cost? I'm gonna build it pretty big, and I want it sturdy.

[hi]

well you can buy them at 8 feet or at 12 feet. i think 6 foot ones are about $10 (give or take a few dollers, it depends where you live). i dont know how much 12 foot ones are.

the easyest way to find out is to go to home depot and look in the wood section.

[mark.f]

Are these going to be quick-creted into the ground, like if you were building a deck foundation? Or are they just going to make a base you could move around?

[Hubb]

Hi is right. They are not that much. In South GA they run about 8 to 10 dollars.

[paaiyan]

I'm going to make a sturdy base, then cross-brace it just in case. I'm not going to use screw to hold it together, I'm going to use bolts and nuts so I can label the parts, disassemble it, then reassemble it on-site. I'll probably stake it down in a couple places once assembled. I'd rather be able to tear it down for transport, because it's going to be big. No cop would pull me over for having lumber in the truck, but I bet they would if I had an 8 foot tall trebuchet in the back.

[paaiyan]

OK, sorry for the double, but I have another question, and I kind of want to make sure the topic stays in the recents so I can get an answer. I just realized that I haven't got a clue what I'm going to use to support the arm. Like I said, this thing is going to be big, 300-400 pound counterweight, and probably between 75-100 pounds for the arm itself. Anyone got any ideas what I could use as an axle for the thing?

[rednecktatertosser]

go to a junkyard, and look for an old rear wheel drive car axle, thats probably your best bet.

[paaiyan]

You know about how much that would be? I'm trying to not spend too much on this thing. For now my idea is a steel pipe with wooden dowels jammed down in it and some concrete ti fill in the space.

[jimmy101]

Paaiyan: You might want to consider putting this thing on wheels, even if you plan on taking it apart for transporting.

1. A treb will usually throw farther if it is on wheels.
2. Wheels significantly decrease the stresses on the treb when it is fired.

[paaiyan]

I was thinking about doing that jimmy. I can always do that later too, my concern right now is my axle, I don't want to shell out the money for the axle from a car, but I want it to be strong.My plan at the moment is a steel pipe, 2 inch perhaps, with wood dowels jammed in it, and if there's any space left, I'll fill it with rebar.

[Hayseed_Andrew]

I have a few points to add, and a few questions.

1. What do you plan on using for weights?
2. My friend and I built one out of fough cut 2X10's on my farm, the base is 8' X 4' and the arm is 12' long. we have 400 pounds of Ford tractor weights on it and they are NOT enough, not even close, so if you plan on building one that big, make sure you have enough weight.
3. Also, if you plan on making one with wheels, make sure you use a fixed counterweight, or if no wheels, you HAVE to have a swinging counterweight. I hope you've done your research.

4. What are you going to use for a trigger?
5. How do you plan on pulling the arm down?

[rednecktatertosser]

i would advise using concrete for filling the pipe,

alternatively, if you found a pretty hefty branch, 2.5 to 3" in diameter, that would work pretty damn well.

[paaiyan]

1. concrete.

2. 10' arm, at least 400 pounds of weight, more if we decide we need it.

3. no wheels, hinged weight.

4. probably i-hooks and a pin. But upon suggestion, for the sake of the contest video, im going to tie the rope off so it wont whip around and cut it with a sword, because I'm cool like that and I have one.

5. rope and pulleys, most likely if i cant get it down, ill hook it up to my truck and pull it that way.

[Hayseed_Andrew]

What are you going to use for weight?

and have you seen this website? http://members.iinet.net.au/~rmine/Grey ... html#frank

I can send or post pictures if you want, but I'd have to take them first

[paaiyan]

I said I was using concrete.

And that was a bad link.