Stir together the flour, sugar, baking powder, and baking soda in a large bowl.
Use a pastry blender or 2 knives to cut in the butter until there are no pieces bigger than a pea.Note: You can also use your fingers but they add heat and will melt the butter some so work quickly.
Make a well in the center and pour in the buttermilk. Stir until mixed in.If needed add a touch more buttermilk to get a dough to form.
Transfer to a lightly floured surface. Lightly knead the dough until it is even consistency.DO NOT overwork the dough or you will have tough biscuits.
Roll or pat into a 1/2-inch thick circle.Use a 2 to 2 1/2 inch biscuit cutter to cut biscuits.
Place biscuits on an ungreased baking dish. Brush the tops with milk.