A cart suitable for supporting a grill, including a grill bowl. The cart has two union members with curved channels for receiving tubular, U-shaped frame members. The union members may be in the form of two similar (but not necessarily identical) halves joined together to enclose the frame members. The tubular channels of the union members resist movement (such as twisting and tilting) in at least two directions. The union members lock the frame members in place with internal protrusions that fit into mating depressions or holes in the frame members. Extra rigidity is added to the cart by one or more side tables which are structural members as well as functional tables. The side tables thus serve as cross-members between two frame assemblies. The grill's lid can easily be tilted back to rest in place on lid supports underneath the bottom edge and contact points on the side tables.