Last year during Christmas Bradley and I talked about building a trebuchet but never did. This year with all the concern about the end of the world on Dec 21 we felt a little more urgency. We did not get it built in time for the end of the world but Bradley has been saying for six months that the Zombie apocalypse is going to happen any day so we decided we had better get prepared.
After a trip to Agri Supply for a bag of bolts and Home Depot for a stack of 2x4s we were ready to build our zombie killer. Bradley, Bobby
We started with building the base legs.
Most of the structure is made of pressure treated 2x4's. We made all the legs and base support beams with 2 2x4's separated by 1 foot long spacer blocks. This was cheaper than 4x4 beams and allowed us to make male and female ends for easy assembly. Note how the axle bar is supported in a V at the top of the two legs.
A quick assembly to check our basic design. Bradley
A nail gun, air compressor and impact wrench are also vital to constructing a zombie killer. Bobby
Details of the top V for the axle.
The bottom of one of the legs. Note the male and female connection with a single 1/2 by 5 inch bolt.
We originally planed to use a swinging tub of water as the counter weight but that caused problems so we switched to a cast iron drainage grate and brake rotor securely fastened with tie down straps.
The bottom leg of an old pair of blue jeans worked well for the pouch. A slab cut from a 10 inch PVC water pipe made a great track. Note the release mechanism is a rope over the arm connected to a release pin.
Close up of the release pin.
Dec 26, 2012 Wed 2:52 PM EST
The throwing arm is 3 feet long on the counter weight end. The throwing arm is 9 feet long from the axle to the tip. 5 feet of the arm consists of double 2x4s with the single 2x4 extending another 4 feet.
This view shows the single side brace. The 2x4s on the bottom keep the base 4 feet apart and square. The metal pipe we used for an axle has a single hole drilled in each end and a lag bolt connects the pipe to the V on top. This keeps the top spaced correctly. The white PVC pipe on the throwing arm that spins on the axle is kept in the center of the axle with a single hose clamp on both sides.
Check out the videos. Note that we changed the counter weight from a swinging bucket of water to chunks of metal after a few throws.
Dec 25, 2012 Tue 5:00 PM EST
Dec 26, 2012 Wed 3:01 PM EST
We have about 10 hours of time in this project. We intend to try more weight, a longer rope on the sling and possibly extend the throwing arm a little. Putting the trebuchet on wheels will make it more efficient and we have some go-kart tires around here someplace. We are currently using water balloons for projectiles but a flaming cat would look pretty cool.
Next comes a proper name and paint job. Only a few bolts hold the whole thing together so we will eventually disassemble it and put it into storage in preparation for the Zombie apocalypse. When the zombies come, we think we can assemble it ready for firing in less than 10 minutes.
Bradley and I had some quality father-son time working on this. It was a lot of fun. My wife was also a great help when she made another hardware run to Agri-Supply for us so we could keep working.
Now to work on a battle plan that integrates our double barreled potato gun into our defenses. Here is a video from 2011.