[sheepherder]

I am thinking this is a casting also...Based on the grainy look of the base, and the 'flat' in the middle of the concave knob...I've made a couple of 'knobs' like this using a ball end mill for the concave part, and while anything is possible, I don't think it is cost effective to add that flat to the end of a ball end mill cutter for a machined base...Just my opinion...