A method and apparatus is disclosed for adjusting the track density by changing the slope of spiral tracks used to servo write a disk drive. A target track density is established for a disk surface, and a plurality of spiral tracks are written to the disk surface in response to the target track density. Each spiral track comprises a high frequency signal interrupted at a predetermined interval by a sync mark, and a slope of the spiral tracks is selected in response to the target track density. The head internal to the disk drive is used to read the spiral tracks in order to write product servo sectors to the disk to define a plurality of data tracks, wherein the slope of the spiral tracks determines the density of the data tracks.