An apparatus for forming an upper edge of a paperboard container includes a pocket including a shell having a cavity with a mouth configured to receive the container along an axis such that the rim extends beyond the mouth. A workstation includes a forming member having a first forming surface which is actuatable toward the axis from a retracted position spaced from the rim to an extended position lying adjacent an upper end of the rim, and a forming segment having a second forming surface which is actuatable along the axis and the forming member in response to axial movement thereof such that the second forming surface is positioned spaced from a lower end of the rim. The second forming surface is actuatable along the axis towards the first forming surface to form the rim therebetween.