While old-fashioned task chairs typically have four wooden legs; their modern counterparts are supported by a single post or pneumatic piston, which has four to six arms radiating horizontally from its lower end. A wheel or caster is attached to the bottom of each arm.
Task chairs, available at discount and office supply stores, are typically sold partially assembled so they require less space during storage and shipping. Simple tools, often only a screwdriver, are needed to complete assembly. Following the manufacturer's instructions, you will attach the lift piston and leg assembly to the chair seat, then screw on the back rest and arms (if included). The stems of the wheels or casters snap into tension bushings or sockets on the bottoms of the chair legs.
Removing the wheels or casters from your task chair typically requires only manual force. To remove a caster, turn the chair on its side. Grasp the caster with one hand, and brace the corresponding chair leg with the other hand. Pull the caster downward (perpendicular to the chair leg) to release its shank from the tension bushing in the leg. Repeat to remove remaining casters.
Rolling task chairs are designed to transmit the weight of the chair and user vertically through the shanks and wheels or casters. The chair legs, without the casters, may not be strong enough to support the weight of an adult. Using the chair without casters may cause the legs to break and could result in injury to the user.