In early casters, the stem of the caster was compelled to swivel in the cast iron retainer or socket. It soon wore rough until it was easier for the wheel to skid side-ways on the floor then it was for the stem to swivel in the socket.
Manufacturers soon realized some of the defects of this type of construction and started using different compositions for treads: such as, felt, fiber, cotton, and rubber. However, they soon discovered that the fault lay in the swivel action, and no matter what type of treads were used, their difficulties continued. They then began to focus their efforts towards producing improved swivel actions. more...
