I don't know why I didn't think of this earlier.
Before you mail-order, try
Grainger I remember one somewhere in DE county. They are most places where you need them. Another option is
Fastenal. Both websites have store locators. I would suspect one of them is near you. If neither one has what you want they can usually have it for you next day, no extra cost. You could always try NAPA, but they are harder to find down there. I'm lucky enough to be sitting within 5 minutes of two major NAPA warehouses.