I documented the steps I took to create our first chandelier, since then I have refined the process a bit and will include tips I have learned from successive productions.
For this first fixture I purchased 6" lengths of steel nipples and cut the 1" sections I needed with a circular saw/ grinder with a fiber wheel. I recommend threading a nut on your nipple before you begin cutting so that when you are done you will be able to "rethread" your cut section by removing the nut. I purchased these materials from Home Depot.
Since then I have found a local hardware that specializes in repairing chandeliers and lamps that carries individual nipples in 1/4" increments. Now I buy as many as I need in whatever length I desire and don't have to worry about fouling threads or sparks.