Heat oven to 400 degrees.
Mix 1/12 cups sugar, the butter, shortening and eggs in a large bowl. Stir in flour, cream of tartar, baking soda and salt. shape dough into 1 1/4 inch balls. Mix 1/4 cup sugar and the cinnamon. Roll balls in cinnamon/sugar mixture. Place 2 inches apart on ungreased cookie sheet. Bake 8 to 10 minutes or until set. Remove from cookie sheet to wire rack. Makes 4 dozen cookies