This light ball caster uses a 1″ diameter plastic ball.
The height of the assembled kit ranges from 1.1″ to 1.4″, depending on the combination of included spacers used. Included dowel pins can be used to reduce the friction between the ball and the ABS housing, but they are not necessary for operation.
This ball caster kit includes a black ABS housing, a 1″ diameter plastic ball, three dowel pin rollers, two spacers (1/16″ and 1/8″ thick), and mounting hardware. The total height of the ball caster, 1.1″, can be increased to about 1.3″ using the included spacers.
The mounting hardware consists three 7/16″ #2 screws and three 1″ #2 screws (and three nuts) so you can pick the most appropriate length for your particular application. You can also use your own #2 or M2 screws if your application requires some other length.
Note that these ball casters are designed for small robots; they are not intended to bear more than a few pounds. With more weight than this, friction between the ball and the housing will generally keep it from rolling well.