Preheat oven to 450. Mix flour, soda, salt, and baking powder. Cut in shortening with a pastry blender. Add buttermilk and mix quickly until dough forms a ball. Turn out on a floured surface and knead a few times. Pat or roll out to a 1/2-inch thickness; then cut with a floured biscuit cutter. Bake approximately 12 mintes biscuits MILK GRAVY: Save 4 tablespoons of pan drippings (or butter) and place over low heat. Stir in 4 tbs. of flour and continue stirring until smooth and bubbly. Add 2 cups milk and stir until thickened. Salt and pepper to taste and serve piping hot.