Hint X3 - Rotating Kid K'NEX rods
There are three ways to support rotating rods in Kid K'NEX models.
The 8-way pivot connector shown opposite is ideal for spinning parts, such as the top of a roundabout, or helicopter rotor.
The set also includes 1-way pivot connector, which is good for supporting axles in swings, vehicles, etc.
If you don't have pivot connectors, then the standard green Kid K'NEX connector has a hole which can be used for a rotating rod.
Note, though, that the rod will not spin as freely using this method as it will using the two special connectors above. This is because they are manufactured from a different type of plastic.