Hi all,  A good source for 1-1/8" copper elbows is W.W. Grainger.  They
are not especially inexpensive (around $3.65 each) but they do work well
and they are a good substitute for the crumbling pot metal elbows that
are found an many of the old player pianos.

Grainger does have an on-line catalog.  You can also access the company
through their many stores throughout the country.  If you are ordering
a quantity of elbows (maybe over 12), you can ask for a quantity
discount.

Best wishes,

Mike Walter