Make a paper-cutting machine
Build a simple, safe paper cutting machine using cardboard, plastic gears, a rubber band motor, and guides to explore mechanical design and safety.
About this activity
Build a simple, safe paper cutting machine using cardboard, plastic gears, a rubber band motor, and guides to explore mechanical design and safety.
What you need
Step by step
- 1
Step 1
Gather all the materials and find a clean flat workspace.
- 2
Step 2
Cut a rectangle of cardboard about 20 cm by 10 cm to use as the base.
- 3
Step 3
Cut two small rectangular support blocks from cardboard and tape or glue them near each end of the base to hold axles.
- 4
Step 4
Push a wooden skewer through the first support block and then through the second so the skewer can spin and fasten the ends under the base with tape.
- 5
Step 5
Slide a plastic gear onto each skewer so the gear teeth face each other and interlock while leaving room for a sheet of paper between them.
- 6
Step 6
Cut two long thin cardboard guide strips and glue them to the base alongside the space between the gears to make a paper feed channel.
- 7
Step 7
Roll a small tight cardboard tube and attach it to one skewer near its gear so it becomes a turning spool on that axle.
- 8
Step 8
Hook one end of a rubber band around the cardboard spool and tape the other end to a small peg or anchored tape on the base to make a simple motor.
- 9
Step 9
Turn the gear with the spool clockwise several times to wind the rubber band and hold the spool steady with your finger so the motor stays wound.
- 10
Step 10
Slide a piece of scrap paper into the guide channel so its edge sits between the interlocking gear teeth.
- 11
Step 11
Release the spool so the rubber band unwinds and the gears spin, pulling the paper between the teeth so it is torn into strips.
- 12
Step 12
Share a photo and a short description of your paper-cutting machine on DIY.org
Fun facts
How do I build a safe, simple paper-cutting machine with cardboard and a rubber band motor?
Start by making a sturdy cardboard base and vertical supports for two axles. Mount plastic gears on the axles, connect them with a rubber band motor (looped to drive one gear), and attach a textured roller or ridged wheel to the output axle. Feed paper between the textured roller and a fixed guide so the roller tears or perforates the paper predictably. Enclose moving parts with cardboard shields and test with adult supervision, adjusting gear ratios for speed and torque.
What materials do I need to make a child-safe paper-cutting machine?
You’ll need thick cardboard for base and shields, plastic gears and axles (toy gearbox parts), a rubber band or twist rubber motor, small rollers or textured wheels, glue and tape, paper clamps or clothespins, and pencils or skewers for axles. Add safety items: cardboard guards, gloves for adults, and masking tape. Use no exposed sharp blades—choose textured rollers or perforating wheels to avoid cutting hazards. Optional: hot glue gun (adult use only).
What ages is this cardboard paper-cutting machine activity suitable for?
This project suits ages 7–12 with adult help. Ages 7–9 can help design, assemble cardboard pieces, and observe gear connections while an adult handles any hot glue or stiff assembly. Ages 10–12 can take more responsibility for gear alignment, testing, and small adjustments under supervision. For younger children (4–6), simplify to exploring gears and rubber-band motors without any cutting or assembly that needs tools.
How can I keep kids safe and what learning benefits does this activity offer?
Prioritize safety: enclose moving parts, avoid exposed blades, supervise all assembly and testing, and keep fingers away from rollers while running. Teach turning off and disconnecting the motor before fixes. Benefits include hands-on lessons in gears, torque, and simple machines, plus fine motor skills, problem solving, and design thinking. Variations: change gear ratios, swap roller textures for different effects, or build a manual crank version for slower speeds.
Watch & Learn
Need help?
What can we use instead of the plastic gears or wooden skewers if those are hard to find?
If you don't have plastic gears, cut matching notches into two bottle caps or cardboard discs to act as gears and use pencils or wooden dowels in place of the wooden skewers as axles, fastening their ends under the 20 cm x 10 cm cardboard base with tape as described.
Why won't the gears pull the paper and how can we fix it?
If the gears don't pull the paper, check that the two gears' teeth interlock with only enough space for one sheet by repositioning the small support blocks, tighten the skewers under the base so axles don't wobble, and wrap a bit of tape around the cardboard spool to increase friction between the rubber band and spool.
How can we adapt the activity for different ages?
For preschoolers, have an adult pre-cut the 20x10 cm base, support blocks, and guide strips and replace sharp wooden skewers with blunt straws or pencils indoors while older children can experiment independently with changing gear sizes, spool placement, and winding the rubber band motor.
How can we improve or personalize the paper-cutting machine?
To personalize and extend the machine, glue different-sized plastic gears or cardboard gear discs to change tear width, add a second cardboard spool to feed two papers, and decorate the base before sharing a photo on DIY.org.