this invention provides an improved compact fine wire incandescent lamp coiled - coil filament and method for making the same . the filament has a secondary mandrel ratio in the range of about 3 . 0 and a primary mandrel ratio which is less than or equal to the secondary mandrel ratio . the length between supports is kept less than or equal to 20 times the secondary diameter . the improved filament design exhibits an increase in compactness and retains or increases structural rigidity while exhibiting minimal sag when the filament is incorporated into an incandescent lamp of the tungsten halogen type variety . the compact coiling method is particulalry useful in designing compact filaments for high voltage applications where it is desirable to eliminate the use of rectifying means to lower the effective voltage across the filament .