go to an industrial supply house, such as McMaster/Carr. you can find round stock from 1/16" to 2" diameter, in brass, bronze, aluminum, stain resistant steel, mild steel, plastics, wood. or go a few pages further and look at steel dowel pins. again, almost any diameter, standard or metric, mild steel, hardened steel or stainless steel.
type "brass round stock" in your internet search, and you should find at least 25 sources and at least half of them do not have a minimum purchase.
the old sailor
old sailors never die, they just spend hours on line trying to save 2 cents on a 50 cent item.