Where can I find threaded brass rod for equip rack

I built a rack for my system a few years ago using MDF and threaded steel rods. I would like to try to replace the steel with threaded brass rod, washers, and nuts. Any idea where I might find such a thing???
Home Depot or hardware store? Plumbing supply store. Any industrial supply company.
If all that fails then try:
they have them at my local Ace hardware in Oakland Calif. i havent seen them at other Ace hardwares, this particualar one caters to contractors. this Ace hardware is on 40th/Manila Streets in Oakland Ca.