cost is amazingly low to make something like this in quantity.. If ya have a place that can cast stainless.. it requires a a good mold plug to be made, and that is the toughtest and most expensive part.. Once the plug is made, a sand mold is made and melted 316 is poured in.. each one has about $20 worth of stainless or less, depending on his source.. There is a little machine time to thread it.. He is not making a killing, but there is room for profit.. The Pacific Northwest (where the stainless elbow comes from) has a lot of small shops available to service the aircraft and oil industry.. If he were picking up scrap 316 from scrap machine turnings from making other parts, he could cut his raw material cost by a bunch. Not saying it is easy, just saying that a guy (or girl) with a desire to make some dollars on the side could do that without much start up cost.
