Home >> Toys >> Other Toys

How to Build a Rat Trap Car

A rat trap car uses the kinetic power in the spring of a rat trap to propel the car. One end of a string is attached to the trap arm and the other is attached to an axle of the car. When the trap is sprung, instead of snapping shut, it pulls the string slowly, turning the wheels and making the car move. The car can be constructed from wheels and axles salvaged from toys or bought at a craft store. The rat trap and other parts can be purchased at home improvement stores. The car can be constructed several ways. This design is one of the easiest to build.

Things You'll Need

Large wooden, spring-style rat trap
String, 10 inches long
4 small eye screws
2 sets of wheels with axles
Masking tape

Instructions

- 1
  Screw two eye screws into one end of the rat trap 1/2 inch from the sides. The screws should be aligned so the openings will hold the axles for the car. Repeat the procedure on the other end.
- 2
  Place masking tape in the center of one of the axles of the car. Insert this axle through the eye screws on the end of the trap where the spring arm will be when the trap is open. Put on the wheels. Insert the other axle and put on its wheels. Ensure that the wheels do not bind against the body of the rat trap.
- 3
  Tie a loop in one end of the length of string. Flip the loop around the masking tape on the back axle and slip the rest of the string through the loop. Pull the string to tighten the loop around the tape on the axle. This will prevent the string from slipping.
- 4
  Set the trap. Wind the string onto the rear axle until all the slack is taken up. To start the car, simply spring the trap with a long stick. As the arm closes, it will pull the string, causing the string to unwind, turning the axle, and propelling the car.

Other Toys