These STL files were designed to allow the user to 3D print the necessary parts to assemble a model of a civil war cannon. Additional listings will be added to my account in the very near future which will contain the STL files to 3D print a matching civil war Caisson as well as a civil war limber. The wheel should be split in half to be printed and then glued together to avoid using support. The wheel can be printed with or without the hub rings. If printed with the hub rings the filament color can be changed at the proper z-axis level to print the hub rings and the wheel separate colors. Prusa does a nice job of managing that process. I recommend printing in PLA and using Testors Cement for Plastic Models to assemble. I use cut sections of carbon fiber archery arrow for axles and barrel pivot but you can use dowels or print your own. I also like to use small fasteners to aid in the assembly. 2-56, 4-40 and 0-80. There are holes provisioned in some of the parts to accomodate this but you can also just glue the model together.