Abstract: The present invention provides a method of fabricating an electric incandescent lamp with improved mechanical stability of its filament, the method comprising the steps of: coiling a first coil of a wire having diameter d around a first mandrel having 5 diameter M1 with a first pitch and a first number of turns; winding said first coil around a second mandrel having diameter M2 with a second pitch and a second number of turns to form a coiled coil filament; mounting and arranging the coiled coil filament within a light permeable envelope; hermetically sealing said envelope, heating the coiled coil filament above its recrystallization temperature within the envelope for recrystallization of said coiled coil. The primary and secondary winding preferably have primary and secondary mandrel-to-wire ratios Y1 and Y2, wherein Y1=M1/d>=3 and Y2=M2/(M1+2d)>3.

Abstract: The mains voltage halogen incandescent lamp has a coiled-coil filament (10) having single-coiled legs (16). In order to obviate sag of the filament barrel (11) when positioned horizontally, the turns (17) of the legs (16) have a pitch (p17) which is larger than the pitch (p12) of the primary turns (12) of the barrel (11).