This makes 2 9-inch unbaked piecrusts.
In a large bowl, mix together the flour, salt, and sugar. Cut butter and shortening into the flour mixture with a pastry blender or fork until the mixture resembles baby peas. Sprinkle the water over the mixture, 1 tablespoon at a time, and blend with a fork. Repeat until the dough is moist enough to come together. Gather the dough into a ball, knead 5 seconds, and then cut into two pieces. Flatten each piece slightly and shape into a disk. Wrap each piece in plastic wrap; chill 20 minutes.
Roll out one of the disks on a lightly floured surface until you have a circle about 12 inches in diameter.
Place dough into 9-inch pie plate, trimming any extra from the edges. Return it to the refrigerator until you are ready to make the pie.