The disclosure describes techniques for erecting cases, and particularly example structures and example methods for use in a case erecting system using a robotic arm. A tool for use in robotic case erecting may be used in conjunction with a robotic arm. Use of the tool assists in keeping a case level as the case moves along a conveyor, where a plow closes the major flaps and a tape head tapes edges of the flaps together, thereby sealing the bottom of the case. The tool also assists in regulating the gap between the major flaps, so that the gap and/or any overlap of the flaps is minimized. Accordingly, the tool assists the robotic arm to close the case in a more precise manner.