A pressing device for forming steel sheet blanks into clips, which comprise curved planking elements and rectilinear stringer elements for connecting a fuselage cell skin to a stringer and to an annular rib in an aircraft fuselage, comprises at least one curved upper tool, at least one curved lower tool, at least one rectilinear upper tool, and at least one rectilinear lower tool. A steel sheet blank is receivable and formable between the at least one curved upper and lower tools and the at least one rectilinear upper and lower tools. The at least one curved upper and lower tool each comprises an upper and lower convexity surface designed to essentially correspond to each other in order to form the curved planking element in a single stroke surface model forming process by simultaneously bending and stamping. The at least one rectilinear upper tool and the at least one rectilinear lower tool each comprises an upper and lower bending surface designed to correspond to each other in order to form the rectilinear stringer element.