Cantilever Tower Project

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Cantilever Tower Project

• 10.0 grams or less
• Minimum arm height 10.0 cm
• Minimum arm length 10.0 cm

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Cantilevered Towers are cranes
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There must be a base

• The base rests on the table

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There are two arms

• One arm is the CANTILEVERED ARM
• This arm holds the 200 gram mass

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There are two arms

• The other arm holds the 500 gram counterweight

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There seems to be two basic styles of
cantilevered towers

• The Tall Crane and the Vee Crane

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Glue, sewing thread and any type of wooden
toothpick may be used

• Remember, thread is your friend!

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Toothpicks come in many shapes

• 10.0 grams uses about 150 flat toothpicks. These
  are weak and vary a lot in quality

Larger and thicker toothpicks weigh more, but are
harder to break.
It is okay to mix the types of toothpicks
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Glue is IMPORTANT

• Do NOT use hot glue
• Hot glue is too flexible and heavy
• Joints will flex
• The tower and arms will bend
• The tower will weigh more than 10.0 grams
• You will be VERY UNHAPPY

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White or Wood Glue

• Easy to use
• Soaks into the wood
• Holds very well
• Easy to clean up
• Does not need ventilation during use
• Does not dry quickly

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Superglues

• Dries quickly - much faster on flesh than on wood
• Does NOT soak into wood
• Accelerator - catalyst to INSTANTLY harden the
  superglue
• Sticks to wax paper and plans

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Epoxies

• Avoid using epoxies
• Heavy after drying
• Must mix in the proper ratio
• Does not dry fast
• Does not soak into wood

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ARM HEIGHT - is measured with a ruler on a right
triangle.
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ARM HEIGHT - is measured to the lowest part of
the arm above the center of the 200 gram mass
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ARM LENGTH - is measured from the front of the
base to the point under the center of the 200
gram mass
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Thread Story

• Do you know why you pull a rope across a street?

Well - have you ever tried to push a rope across
a street?
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Thread works well under tension forces
Tension forces pull things apart
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Tension Forces
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Thread does NOT work well under compressional
forces
Compressional forces PUSH things apart
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Thread is your FRIEND!

• Sewing thread is light and strong

• Thread works well under tension

• Thread does not work well under compression forces

• Thread is light and does NOT add a lot of mass!

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Rectangles and squares easily deform under
pressure. This does NOT make a strong and
well-constructed tower.
Force
Tower
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The tower will lean to the right or the left.
Once leaning starts, breaking soon occurs
Force
Tower
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Triangles make for strong towers
The more triangles, the stronger the tower
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Triangles strengthen towers by keeping the tower
rigid.
The diagonal prevents the deformation of the
shape
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• The more triangles, the stronger the shape. This
  is true for both vertical and horizontal parts of
  the tower.

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Time to Build
Plan on several hours to draw plans, revise then
build a tower.

• No matter how much time you plan on, you will
  need more than you think.

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Building Supplies

• Cardboard
• Wax Paper
• Sewing Pins
• Tape
• Fingernail Clippers or
• Diagonal Cutters

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Cardboard

• Use corrugated cardboard to build upon.

The pins easily stick into the cardboard..
The entire set up may be easily picked up, moved
and stored.
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Add photo of cardboard with pins sticking out of
it
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Plans

• Draw plans the actual size
• the tower will be

Use a ruler to draw straight lines
Avoid making spans larger than the toothpicks to
be used in building
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Insert photo of drawing plans with a ruler
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Include photo showing toothpick and spans smaller
than a toothpick
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Place the plans on the cardboard.

• Tape the plans down so the plans cannot move.

Cover the plans with wax paper to protect the
plans from glue.
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Tape the plans onto the cardboard
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Place wax paper over the plans
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Place toothpicks over the plans
Put glue on a toothpick and add it to the plans.

• Use pins to hold the toothpicks in place until
  the glue dries.

When the side is finished, take out all the pins
and remove the side from the wax paper.
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Place toothpicks on the plans
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Use nail clippers or diagonal wire cutters to cut
toothpicks to the correct length
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Put glue on toothpicks to be added to the tower
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Use pins to hold the toothpicks in place
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Use a box to protect and carry the tower
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If the tower breaks before it is tested, it MUST
be repaired or rebuilt for a grade to be earned.
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The diagrams, answers to the questions and the
sign off sheet should be turned in before leaving
school the day the tower is due
Make the diagrams BEFORE testing the tower (Just
in case the tower breaks)
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The Tower Project is worth 150 points, but more
points than this may be earned

• Towers may be tested early to help ensure a
• good grade.

Dont wait to start working!
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Cantilever Tower Project

• 10.0 grams or less
• Minimum arm height 10.0 cm
• Minimum arm length 10.0 cm