Cheap Pulley

In the physics classroom, we often use pulleys as a part of labs or demonstrations. The downside to using pulleys is the amount of set up time beforehand. These simple pulleys can be attached to lab tables, whiteboards, etc using command strips.
A skateboard bearing is friction fit into the wheel of the pulley and then attached to the base. the bearing needs to have an outer diameter of 22 mm and an inner diameter of 8 mm.