Boil potatoes in skins until partially cooked; cool, peel, and grate. Divide potatoes in 3 equal portions. In a large round crockpot, put in a layer of grated potatoes, salt and pepper, half stick of butter, cut into pats, 1 cup shredded cheese. Repeat this procedure two more times, then pour milk over this. Cover and cook on MEDIUM heat for 2.5 hours, the last half hour put on HIGH.