About this 3D model

I am making a chamber for my RepRap and wanted to put it on Rubber Feet. They were expensive at the hardware store ($6.00 each) so I purchased a pack of 4 rubber tips and made some inserts to go in them. Total price $2.19 for the feet and 49 cents for the carriage bolts and nuts. Parts List 4 1/4 in. Carriage Bolts of the length you need 4 Nuts to fit 4 Slip on rubber feet like the ones pictured