Music wire or piano wire is tempered high carbon steel, spring steel,it's used in lots of Hobbys including remote control airplanes. I bought a tube of 20 pieces 36 in. long in early 80's. Mine measures .062 and after I drill through with 1/16 bit I take the barrel or ramrod pipes ect. out and drill the metal again with a #52 because most 1/16 bits are undersized and makes it difficult to tap the pin through. Jerry