Not sure what kind of caster to use for your project? Consider this.
According to DIY Network:
“Casters fall into two categories: furniture and shop equipment casters.
“Plastic furniture casters have two wheels and move well on carpet. They are light-duty casters and cannot carry a great deal of weight. They are long-duration tools.
“Hard rubber wheel casters swivel in all directions for increased mobility. They are more durable than plastic wheels.
“They are plate-mounted with screws going right into the board.
“Use casters with stems for furniture with legs. They are mounted with sleeves that are inserted into the legs of the piece of furniture.
“When you do not want casters to show, attach a skirt to the plywood base on which the casters are mounted.
“Most shop equipment casters are plate-mounted. Light-duty, inexpensive plastic shop casters that do not swivel are hard to maneuver around corners. They do not roll over electrical cords. It is possible to purchase swiveling shop casters — but that type still won’t roll over electrical cords.
“Heavy-duty steel wheel casters can carry a large load, despite the small size. When they are loaded down, they are difficult to get over obstacles, like power cords.
“Durable, hard rubber shop casters have locks with teeth on them to keep the wheels from rolling when you want them to remain stationary. These wheels have no problem going over electrical cords when loaded down.
“Use large casters if you have to drive over cables. Four swiveling wheels provide the most maneuverability. If you have two swivel and two fixed wheels, you will still have problems moving the casters in some directions. Use casters with locking wheels to keep the unit from rolling.”