Finn Juhl Chieftain chair arm rest replacements  

I think the hard thing is finding a blacksmith who is dedicated enough to study the forms of the arm rest to get it 100%

@halcyon

Got a tech school nearby? Could be a good be a good independent-study project for a budding engineering student. Hand-forming sheet metal like that is a dying art. There are still experts around, though. Shops that specialize in restoring vintage Italian race cars, for example, often have the tools and expertise with reproducing body panels and could pull these off with proper dimensions/drawings to work from.

@herringbone

The Eames(es) did all that developing their leg splints! Forming laminations like those gets complicated, involving 2-part moulds, heavy presses, etc., etc., etc. Laying up fiberglass in 1-part mould would be simpler, IMO. But, with steel, you could weld the fasteners on!