The stamp battery is the heart of a gold mill. With the stamps pounding up to 90 beats each minute, the roar of a mill could be heard for miles around. Stamp milling is the process of freeing gold from the encasing valueless minerals. Metal stamps are lifted by rotating cams that raise tappets, secured to the top of the stamp rod. As the cam rotates out from under the tappet the stamp drops by gravity, crushing the rock beneath it. Our 10-stamp battery consists of 72 white metal castings, wire, strip wood, and wood blocks, which include notched stamp posts, mortar blocks, and all wood needed for the stamp battery, walkways, and two amalgamation tables. The battery includes 2 mortars with screens, 10 each tappets, cams, stamps, and latch fingers, an idler wheel, 72" diameter camshaft pulley, 39" diameter drive pulley, and water line castings. The O scale stamp battery is over 5 1/2" high.