A pen assembling press includes a base, a press unit, a carriage, and a positioning arrangement. Actuation of a lever moves an engagement head relative to the base along an actuation axis. A second engagement head is coaxial with the first engagement head. The carriage is movably mounted to the base. The positioning arrangement includes a slot, a plurality of recesses and a pin. The slot extends through the first leg in a direction perpendicular to the actuation axis. The slot has a constant height section having a height. The pin has a shaft and a head. The head is receivable in the recesses. The shaft has a thickness being substantially equal to the height of the constant height section of the slot. The pin is movable relative to the carriage along a pin axis that is perpendicular to the actuation axis to selectively engage and disengage the recesses.