A method of manufacturing gas and/or fuel swirlers for fuel injectors and combustor domes and cone-shaped swirlers so manufactured are disclosed. The disclosed conical swirlers feature cut-through slots on a cone-shaped body. The contour and spacing of the slots are configured and arranged to accommodate a wide range of requirements for fluid flow areas and swirl strengths. Preferably, the cone-shaped swirlers can be manufactured by wire EDM processing. More preferably, multiple cone-shaped swirlers can be manufactured simultaneously by nesting swirler blanks in a stack and wire EDM processing the stack as a unit. The cone-shaped pinwheel swirler fits well into various fuel injector heads, enabling the injectors to reduce the frontal surface area and flat area for minimal potential of carbon formation.