Cautionary and Warning Statement
• This kit is designed and intended for educational purposes only.
• Use only under the direct supervision of an adult who has read and understood the instructions provided in this user guide.
• Read warnings on packaging and this user guide carefully.
• Safety glasses required.
• Do not aim at people.
• Always exercise caution when using sharp tools.
How a Trebuchet Works
If you’ve ever read about what life was like during medieval times, you’ll know there were wars during this
period in which ghting was much more hands on and weapons were far less sophisticated than today.
The invention of the trebuchet put a twist on what people knew as a catapult. Both machines were used
to ing huge rocks that would break down the walls of a castle and let invaders inside. Instead of throwing
weight on one end of the catapult’s lever to propel the rocks forward, the trebuchet has a sling that swings
from the bottom to the top of the machine, giving it more momentum and projectile force.
Materials Included
• Basswood sheets with laser-cut pieces • 1/4" x 1" flexible tubing
• Design template for bending paper clips • Large paper clips (2)
• 1" x 12" basswood strip • Strip of ripstop nylon
• 1/4" x 4-3/4" basswood strips (4) • 36" piece of nylon string
• 1/8" x 3" brass tube • 1/8" brass washers (2)
• 5/32" x 1/2" brass tube • 2 lever arm end caps (1-1/2" x 2" punch out piece)
Items Required (not included)
• White glue or CA glue • Sandpaper
• Hobby knife • Ruler
• Needle-nose pliers • Scissors
• Safety glasses • Mass plates (required for launch; Pitsco product #58676)
• Felt-tip marker • Modeling clay (to make projectiles)
Building the Base
1. Punch out the trebuchet body pieces from the basswood
template. The two small base pieces t at the bottom of the
Y-shaped side pieces. Glue them onto the bottom of one side
piece.
Steps 1-2
2. Glue the other side piece on top and let dry. These will form a at
square on the bottom that will be the base.
Trebuchet User Guide 58670 V0313 1
3. Locate the 1" x 12"
strip of basswood.
Measure and mark
4-3/4" from one end.
4. Glue the strip into the precut notches of the small base
pieces so that the mark lines up with an outside edge of
the base. The strip should be centered over the base.
5. After the basswood strip is dry, locate the four 1/4" x
4-3/4" strips; these will be base supports. Take two of
them and cut a shallow notch (1/16" deep) 1/4" from one
end.
6. Line up the notched strips so they ll in the gaps
between the bottom of the basswood strip and the
square base on one side. The notches go toward the end
of the long strip and will create small holes when placed
against the basswood strip. Without cutting notches,
place the second pair of base supports on the other side.
Step 3
Step 4
Step 5
Step 6
7. Using needle-nose pliers, straighten one of the paper
clips. Using the cutter on the inside of the pliers, cut a
2-5/8" piece o the paper clip and bend that piece into a
triangular shape like that shown above “Trigger” on the
template.
8. Slide the ends of the triangle through the holes at the
front of the basswood strip (formed by the notches in the
small strips) so the triangle forms a hook.
Step 7
Step 8
2 Trebuchet User Guide 58670 V0313
Building the Lever Arm
1. Find the long basswood piece with the rounded end.
This is the lever arm. The two diagonal cuts at one
end are identical to the small end caps on the separate
1-1/2" x 2" piece. Glue the end caps to each side of
the lever arm’s curved end. The curved end caps may
extend a little past the lever arm, but make sure the
diagonal cuts are lined up.
2. The lever arm has a small hole near its center;
locate the short brass tube. Center the
tube in the hole and glue it in place so
it doesn’t spin.
3. Take what is left of the paper clip and
cut o 1-1/4" with the needle-nose
pliers. Bend the piece with the pliers to
match the shape where the template
says “Hook.” Make sure both ends
are smooth; remove any burrs with
sandpaper. This will be the hook.
Step 3
Steps 1-2
Step 4
4. Line up the hook against the square end of the lever so that it
is over the notch and hanging over the end of the lever about
1/2". Glue the hook to the arm. Let it dry for a few minutes,
locate the 36" piece of string, and cut o 12". Holding the
(nearly dry) hook in place, wrap the string around it so the hook
is bound to the lever arm. Put a layer of glue over the string so
it does not come unwound. Be sure not to glue the notch.
5. Locate the long brass tube, and slide it through the short brass
tube glued into the lever.
Step 6 Step 7
6. Using scissors, cut the
exible tubing into four
1/4" pieces.
7. Slide a brass washer
onto each end of the
long brass tube, and
push one of the tubing
pieces onto either end.
Step 5
Trebuchet User Guide 58670 V0313 3
8. Put each end of the brass tube through the holes in the side
pieces of the base. Be sure the hook is on the same end as
the trigger and the diagonal cuts are facing upward.
9. Push the last two exible tubing pieces onto the outside
ends of the brass tube to connect it to the sides. Be sure the
lever can swing freely.
Building the Sling
Steps 8-9
1. Locate the piece of nylon
and the remaining 24" of
string. Trim each corner
of the ripstop nylon at an
angle, and use a hobby
knife to punch a tiny hole
into each end.
2. Cut the string in half. Tie a
piece to each end of the
nylon strip through the holes. This will be the sling.
3. Take the free end of one string and tie it into a secure
loop.
4. The free end of the second string should be carefully
threaded through the hole created by the hook on the
square end of the lever arm. Tie this end into a knot so it
stays connected to the arm. Use a dab of glue to make
sure the knot doesn’t come loose.
Note: It is very important that the strings are the same
length. They should each be close to 8" so that the sling
isn’t lopsided.
Step 1
Step 2
Step 4
Steps 1-2
Adding the Counterweight
1. Straighten the second large paper clip. Look at the area on the design template
labeled “Weight support,” and bend the clip into a narrow, upside down U-shape
with sharp corners. Be sure the loop of the U is narrow enough to t through the
center holes of the mass plates.
2. Place the mass plates on the weight support.
4 Trebuchet User Guide 58670 V0313
3. Slide the clip onto one of the diagonal cuts in the lever arm. The
weight will provide resistance in order for you to pull downward
on the square end of the lever arm.
Operating the Trebuchet
1. Loop the free end of the string over the hook.
2. Raise the trigger and put the hook under it.
3. Gently lay the sling along the long basswood base piece inside the
trebuchet body.
Step 3
Step 2
4. Find your projectile and tuck it inside the nylon material. It’s a good
idea to start with 100 grams of weight for every gram of clay.
Steps 3-4
5. Pull down on the trigger to release the lever and ing
the clay across the room.
Your trebuchet is ready to attack! The trebuchet can pitch
ammunition many feet away, so be sure to only use nondamaging materials.
Experiment with dierent amounts of mass, lengths of
string, and angles of the hook to ing the balls higher or
farther. To set the scene, build protective walls or set up a
target.
Caution: Before ring the trebuchet, safety goggles or
glasses should be worn by everyone in the room.
Trebuchet User Guide 58670 V0313 5
Activity Idea
Using the built Trebuchet Kit, students will launch small balls of clay while using various numbers of mass
plates. Students measure the resulting ranges and graph them.
Preparation
Set up a ring range by rolling out a 30-foot length of two-foot-wide white paper (Pitsco Range Paper) or
a similar type of paper. Tape this down so it doesn’t move. If many students do this experiment with their
individual trebuchets, be sure they each have a clay ball that has the same mass (for example, 10 grams of
clay).
You will also need a measuring tape and a student to watch the landing and record the results.
Testing Dierent Numbers of Mass Plates
Add four mass plates to the trebuchet and set the model at one end of the paper. Place the clay ball into
the sling and set the trigger. Launch the ball and record the result in the table below. Repeat this twice
more with the same number of mass plates. Then, average the three ranges and record this average in the
Average range column.
Number of
mass plates
4
6
8
10
12
14
Repeat this process for the other numbers of mass plates. After all tests have been completed, predict
the range of a teacher-specied odd number of mass plates. After making your prediction and writing it
down, test this number of mass plates and answer the questions below.
What was the range?
Was your prediction accurate?
Trial 1 range
(cm)
Trial 2 range
(cm)
Trial 3 range
(cm)
Average
range (cm)
What did you learn about the connection between the amount of mass used and the resulting range?
What do you think would happen if you changed the mass of the clay ball?
6 Trebuchet User Guide 58670 V0313
Want more activities?
You can nd more activity ideas at shop.pitsco.com. Search for Trebuchet Kit, click on it, and then click the
Activities tab.
Trebuchet User Guide 58670 V0313 7
Kit
32897
V0210
58670 V0313
Trebuchet
shop.pitsco.com
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P.O. Box 1708 • Pittsburg, KS 66762
User Guide
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