Mix 3 cups sugar, margarine, shortening and eggs. Combine flour, cream of tartar, baking soda and salt; blend into creamed mixture. Shape dough by rounded teaspoonfuls into balls.
Mix 6 tablespoons sugar and 4 teaspoons cinnamon. Roll balls in mixture to coat.
Place about 2 inches apart on ungreased cookie sheets. Bake until set, 8 to 10 minutes. Immediately remove to wire racks. Makes 6 dozen cookies. Recipe may be halved.
Notes
If using self-rising flour, omit cream of tartar, baking soda and salt.