Columbia Machine Works was contracted to fabricate two 11′ diameter furnace rings for a refractory customer. These rings were burned out on our CNC plasma table out of two pieces of 2″ A36 plate, then welded at the seams with 100% joint penetration. They were then put on the boring mill to receive 40 equally-spaced, drilled and counterbored holes around the full diameter. Then we faced off the weld seams for clean-up, then inspected the rings for quality. Since we not only have a large CNC machine shop but also a sizable fabrication shop under the same roof, the work flow for these rings was very smooth.