Grinding is a very complex machining process. Single grain grinding methods are useful to study complex grinding action. Very low speed single-grain grinding tests were carried out for 45 steel and 20Cr alloy with 14# ZA grain. The grinding groove width and depth, the grinding force ratio, specific grinding forces, and grain wear and fracture are studied. The plowing decreases with the grinding section area or grinding depth increase. The average tangential force at grain fracture in the experiments is 54.4N; the average normal force at grain fracture is 949.6N. The ratio of tangential-to-normal force varies suddenly when grain fracture.