Abstract: Rod-like tools mounted on gears so as to be swung together and apart by a reciprocating drive and running across a conveyor intermittently moving loaded egg containers, likewise oriented across the conveyor, are moved together to fold over the top corrugated strips of the upstanding sides of the egg container, as presented to the machine, by 90.degree., to bring these strips into abuttment. Each corrugated strip is backed by a flat strip and one of the two has tabs which are folded over by 180.degree. and adhesively bonded to the other flat strip. The folding over of the tabs is performed by a set of fingers that move between segments of the first-mentioned folding tools to raise the tabs at an oblique angle, after which push rods bend them over completely.