Stop in for a cup of coffee

K... so.. stupid question.. i need to make spacers for the long bolt on my alternator and will need to make one or 2 for my power steering pump.. I have been trying to find thick wall tubing with a 5/16 (might be 3/8) ID hole in the center... i think i am just search from wrong terms like "Hollow aluminum tubing" Anyone have the proper name to search for?