custom services performed on and to metal, namely, welding, swaging, drawing, cutting, bending, flaring, upsetting, bulging, punching, grinding, brazing, annealing, passivation, deburring, machining, micro-machining and polishing of metal to the specifications of others; custom fabrication and manufacture of metal goods and assemblies; custom tooling to the order and specifications of others for manufacture of metal goods and assemblies; prototype fabrication of new products for others; and device assembly for others