Preheat the oven to 425°F. Mix all the dry ingredients together in a bowl. With a pastry blender, or two knives cut the shortening into the dry mixture until it has the consistency of coarse cornmeal. (I've seen this done with two butter knives, but personally, I'd be lost without a pastry blender!) Add the milk while gently stirring with a fork. The dough that forms should be soft, but not sticky. You may have to add a little more or less depending on the temperature and humidity of your kitchen. You'll have to experiment until you learn the "feel" of the dough. Knead the dough on a floured board until smooth. DO NOT OVERWORK! Overworked biscuits will be tough! A friend of mine once said "Just flip it over and smack it twice . . . .don't work it no more!" Roll out the dough, or pat it flat. Cut with a biscuit cutter or a glass tumbler and place on a lightly greased baking sheet about 1 inch apart. This recipe makes about a dozen biscuits about 3 inches across and a half inch tall (unbaked). You can make them thicker, of course, but remember that they will rise up as they bake. Bake 12-15 minutes, or until golden brown. Serve these with Frank's Famous Sausage Gravy . . . but you had better make a double batch! You wouldn't want to make that combo every day, though . . . too much fat and cholesterol!