I have just finished my prototype rail/rods system, made of aluminum, but I want to upgrade to graphite. Where is a good source (read as inexpensive ;) ) for this?

There is none for stsndard rod diamaters - though there are some imperial measurement graphite suppliers online.

-j

What diameter of aluminum did you use?

I wouldn't use aluminum for rails. You will forever be cursing the black aluminum oxide on your hands. Use stainless or carbon.

You will likely find 5/8" stainless (.049" wall) rod at Home Depot. 5/8" is 15.875mm, slightly larger than standard 15mm.

They are approx, 8mm in diameter.