I was told it was a torpedo gyroscope from a MK37 Korean War era torpedo. Spins effortlessly on three axis. When electrified, the center steel disk would spin at a high rate of speed, thus wanting to hold that position, while all outside movement is corrected by the other axis. It is truly a work of industrial art and a great conversation piece.
The item "Vintage Torpedo Gyroscope Military USMK37 Korean War era ordinance gyro" is in sale since Wednesday, May 2, 2018. This item is in the category "Collectibles\Militaria\WW II (1939-45)\Original Period Items\United States\Machine Parts & Accessories".
The seller is "tiadaghtonjim" and is located in Jersey Shore, Pennsylvania. This item can be shipped to United States.