The FIRST EVER (Free) COMPLETE GUIDE FOR CREATING YOUR VERY OWN FLOATING ARM TREBUCHET
Of this size, anyway. When i was looking for a good set of plans for a floating arm trebuchet, i couldn't find a single free one. I know that a lot of people share my frustration in not being able to find free plans- so I wanted to create the first one. This is a guide that will show you exactly how to build one. As always, let me know if there is anything I can do to improve it-and I will add a video after I figure out how to.
I had a school science project (not fun) so I wanted to make it fun by building something cool. My friend and I previously made a catapult that was 7 feet high, and threw a baseball 40 ft. It was pretty bad. So this is a way to make up for that. The height of the channels is 8 feet, But the arm rises higher than that in its resting position. The arm is 7 feet. The short arm/ long arm ratio is what I was testing, and the different ratios are 2:1, 2.5:1, 3:1 and 3.5:1. I won't tell you which one was the best yet, although you can probably guess. The counterweight is about 36 pounds, but the big, wide wood piece (the short arm) was probably around 20 lbs. I'm still not quite sure... The total cost for me was around 130$. I don't think it was more than that.
If you want more information on how a floating arm trebuchet works, there are plenty of videos on the internet.
I would visit Ron Toms's site, he's the inventor of this type of trebuchet.
I want to apologize for not having very many pictures of the building process, but I made sketchup models, so hopefully they will help. There are several things that could be improved, which are listed on the last page. The first good throw was about 206 feet, although the trajectory was way too steep, to the point where we could not see the baseball. So, I'm guessing that a baseball would go in excess of 300 feet! And that's with only about 50 pounds of counterweight. A 1 lb projectile would probably go about the same distance. Trust me, it's powerful. We just need to fix the pin and find the best sling length. The sling length is also probably not perfect. I'm still tweaking. Most throws went either straight down or backwards. The backwards throws were caused by a glitch in the guide system for the arm as it falls. The pin was also previously a double-headed nail and a keychain ring. The ridges in that ring would sometimes get caught on the two heads of the nail, which we think is the reason for the downward throws. So, you should include in this project the turnbuckle pin system, which is based off of this trebuchet: http://www.trebuchet.com/10101
The entire thing took me about 2 months to build, but I wasn't working on it every day.
The diagonal 2 X 6s that attach to the longer drop shannel diagonals were not included in this instructable because they were a lot of trouble to add to it and I don't think they were really needed or worth it.
Always be careful; never fire it around windows or people.
Also, be very careful with the trigger. When you pull it out, it tends to fly towards the person pulling the trigger very quickly. Always hold the rope at the very end and jump out of the way after you pull it.
Oh but wait before you do...Remember to look at EVERY SINGLE ONE of the picture notes. I'm sure they'll help you a lot...
Credits: (Yes I just had to)
My mom and dad for paying for (almost) all of it
and for putting up with a messy cluttered garage
My friend, Michael, for always helping me with the loading and firing.
My neighbor and.. older friend, Joe, (He's an adult) for giving me tips on building the thing, especially the trigger design. He always believed it would work, unlike my dad. But my dad payed for most of it so I can't complain.
Coby helped move the trebuchet back from school (His grandpa has a pickup truck) and also helped me load and fire on one of the testing days.
Thank you to everyone that helped.
Step 1: Materials
2 segments of 6 ft. (1.8288 m) long 2 X 4
These are the horizontal beams that are used as the track.
2 segments of 6 ft. (1.8288 m) long 1 X 6
Long sides of the base
2 segments of 2 ft (0.6096 m) 1 X 6
Short sides of the base
*It would be better if the two previous 1 X 6 pieces were 2 X 6, I'll explain later.
2 segments of 6 ft., 2 in. (1.8796 m) long 2 X 4
2 segments of 5 ft., 10 in (1.7272 m) long 2 X 4
The two previous segments are diagonal supports. Cut at least 3 inches longer unless you are very good at cutting angles accurately (A miter saw would help)\
2 segments of 8 ft (2.4384 m) long 2 X 4
These will be the drop channels
*look at the last step: improvements. This may need to be changed.
8 segments of 3 ft., 6 in (1.0668 m) long 2 X 4
Main track supports
look in improvements, may need to be changed
4 segments of 4 ft., 5 in. (1.3462 m) long 2 X 4
These are the pieces of wood directly on either side of the drop channels.
2 segments of 2 ft., 11 in. (0.889 m) long 2 X 6
3 segments of 3 ft (0.9144 m) long 2 X 6
More diagonal supports. These Are not included in the instructable because I did not think they were necessary. I might include them later. If you really want to include them, they should also be cut about 3 inches longer, until you know what to cut.
2 segments of 1 ft., 0.5 in. (0.3175 m) long 2 X 4
2 segments of 2 ft. (0.6096 m) long 2 X 4
extra lateral support
4 segments of 1 ft., 5 in. (0.4318 m) long 2 X 4
4 segments of 1 ft., 5 in. (0.4318 m) long 2 X 6
diagonal supports, lateral and track-supporting
2 segments of 3 ft. (0.9144 m) long 2 X 4
6 segments of 2 ft., 5 in. (0.7112 m) long 2 X 4
These make up the short arm
May need to be shortened, look at improvements
2 rectangles of 3/4" in. (2.54 cm.) thick plywood, 2 ft., 5 in. X 3.5 in. (0.7112 X 0.0889 m)
Plywood also included in the arm
1 segment of 7 ft. long 2 X 4
the arm itself
2 rectangles of 3/4 inch (1.905 cm) thick wood, 1.5 in. by 2 in (0.381 X 0.0508 m)
The two bits at the open top of the cut channel..keeps the drop channel from "opening"
*look at the last step, improvements. This may need to be changed
4 rectangles of 3/4 inch (1.905 cm) thick wood 9.5 X 5.5 in (0.2413 X 0.1397 m)
4 rectangles of 3/4 inch (1.905 cm) thick wood 9 X 4 in. (0.2286 X 0.1016 m)
4 rectangles of 3/4 inch (1.905 cm) thick wood 9.5 X 9 in. (0.2413 X 0.2286m)
Threee previous sections are for the counterweight boxes. This might change depending on your weights setup. This is what fit for me. Also, 1 inch thick wood would would be stronger.
about 250 2.5 in. (6.35 cm.) wood screws, phillips head drive, #8
I would get more in case some of their heads strip...
if you buy pt lumber make sure they are approved for use in it..
8 .5 in. (1.27 cm) wood screws, phillips head drive, # 8
16 1.5 in (3.81 cm.) wood screws, phillips head drive, #8
3 ft. (0.9144 m.) long 5/8 in. (1.5875 cm.) diameter threaded rod, coarse thread
NEEDS TO BE MADE THICKER: LOOK AT IMPROVEMENTS
2 segments of 2 ft. (0.6096 m.) long 5/8 in. (1.5875 cm.) diameter threaded rod, coarse thread
May need to be made thicker
20 5/8 in. (1.5875 cm.) nuts, coarse thread
for the threaded rod
24 5/8 in. (1.5875 cm.) washers
again for the threaded rod
10 1/4 in. (0.635 cm) diameter, 5.5 in. (15.24 cm.) long carriage bolts
For the arm assembly
6 1/4 in. (0.635 cm) bolts, matching thread
for the carriage bolts
6 1/4 in. (0.635 cm) washers, matching carriage bolts
for the carriage bolts
3/8” X 4” eye bolt (Including bolts)
8 matching cut washers
these will be used in the trigger
2 1/2” X 10” eye bolts
these are the trigger pins
3 3 in. X 1.5 in. (7.62 X 3.81 cm) diameter wheels, 5/8 id bearing load rating of 200 lbs (90.71 kilos) or more
May need to be hanged if the diameter of the threaded rod is changed
excellent site for cheap, strong wheels http://www.thecasterguy.com/
2 hand weights, 10 lbs (4.54 kilos)*
2 hand weights, 8 lbs (3.63 kilos)*
*must be able to fit inside counterweight boxes
Approx. 50 ft. (15.34 m) of 3/16” (0.47625 cm) braided polyester cord
The sling lines, I bough 50 ft because i needed to cut the right lengths for each ratio, you probably wont really need more than 15 ft.
Approx 25 ft. (7.62 m)1/2” braided nylon rope
(This is actually for the trigger)
15 in. X 6.5 in (38.1 X 16.51 cm.) denim fabric
for the sling
Just find a pair of old jeans
Approx. 10 ft. (3.048 m ) of gorilla tape
for the sling
1 keychain ring
A solid metal ring of any kind would work better.
One thick nail.
This is the pin.
I don't know what gauge mine was, I found it in the trash Buy one that is at least 4 inches. The thicker the better to prevent it from bending. You should also cut off the head if you keep getting downward throws no matter how you adjust it.
If you want a better pin system, look at the turnbuckle pin system here.
(third picture on the right) RLT industries trebuchet.com
hacksaw if you don't have a METAL CUTTING BLADE FOR YOUR JIGSAW,
jigsaw the one I used here
circular saw (The one I used here) OR miter saw AND table saw
you need to miter, rip, and crosscut.
drill (The one I used here came in a kit here) with a varied drill bit set, for pilot holes, etc. One drill bit MUST be the size of your threaded rod (Mine was 5/8", it should be thicker) Ideally, the drill bit would be a foot long, or 6 inches, so that the holes in the arm don't become misaligned. I'll explain later...
also screwdriver bit driving in your screws.
coping saw and orbital sander (The one I used here)
Socket wrench for your threaded rod
...I'm kinda adding these as I think of them..
Tape measure, ruler
I think that's it
OK onto step 1