A duct making apparatus, comprising: a first station configured to accept a formable sheet material, said first station including a first mechanism for forming one of a male lock bend and a female lock seam in a leading edge of said formable sheet material; a second station disposed to define an axis of travel of said sheet material from said first station to said second station; and - a third station arranged to form the other of said male lock bend and said female lock seam on a trailing edge of said formable sheet material characterized in that: - said second station has a retractable conveyor, said retractable conveyor being selectively movable from a first position in which said retractable conveyor is in close association with said first station, to a second position in which said retractable conveyor is spaced apart from said first station forming thereby a void between said first station and said second station; said third station includes a roll forming assembly, said roll forming assembly being selectively movable in a direction substantially orthogonal to moving direction of said retractable conveyor and substantially orthogonal to said axis of travel of said sheet material, said third station being further arranged to form the other of said male lock bend and said female lock seam on the trailing edge of said formable sheet material when said retractable conveyor is in said second position and when a portion of said roll forming assembly is selectively inserted into said void via said movement of the roll forming assembly in said direction substantially orthogonal to moving direction of said retractable conveyor. a first station configured to accept a formable sheet material, said first station including a first mechanism for forming one of a male lock bend and a female lock seam in a leading edge of said formable sheet material; a second station disposed to define an axis of travel of said sheet material from said first station to said second station; and - a third station arranged to form the other of said male lock bend and said female lock seam on a trailing edge of said formable sheet material characterized in that: - said second station has a retractable conveyor, said retractable conveyor being selectively movable from a first position in which said retractable conveyor is in close association with said first station, to a second position in which said retractable conveyor is spaced apart from said first station forming thereby a void between said first station and said second station; said third station includes a roll forming assembly, said roll forming assembly being selectively movable in a direction substantially orthogonal to moving direction of said retractable conveyor and substantially orthogonal to said axis of travel of said sheet material, said third station being further arranged to form the other of said male lock bend and said female lock seam on the trailing edge of said formable sheet material when said retractable conveyor is in said second position and when a portion of said roll forming assembly is selectively inserted into said void via said movement of the roll forming assembly in said direction substantially orthogonal to moving direction of said retractable conveyor. - a third station arranged to form the other of said male lock bend and said female lock seam on a trailing edge of said formable sheet material characterized in that: - said second station has a retractable conveyor, said retractable conveyor being selectively movable from a first position in which said retractable conveyor is in close association with said first station, to a second position in which said retractable conveyor is spaced apart from said first station forming thereby a void between said first station and said second station; said third station includes a roll forming assembly, said roll forming assembly being selectively movable in a direction substantially orthogonal to moving direction of said retractable conveyor and substantially orthogonal to said axis of travel of said sheet material, said third station being further arranged to form the other of said male lock bend and said female lock seam on the trailing edge of said formable sheet material when said retractable conveyor is in said second position and when a portion of said roll forming assembly is selectively inserted into said void via said movement of the roll forming assembly in said direction substantially orthogonal to moving direction of said retractable conveyor.