Abstract: Apparatus for expanding the mouth of a hollow article, said apparatus comprising a rotary expansion tool and a holding pad reciprocable towards and away from the tool. The rotary expansion tool includes a cage, a plurality of rolls held in equispaced relationship by the cage around an inner race which holds the rolls in rolling engagement with the outer race. Means within the tool cause the rolls to roll within the outer race, each of said rolls having a work portion, extending in an axial direction from the outer race. The work portions enter the mouth of an article pushed into engagement therewith by the pad, to expand the mouth an axial distance determined by the length of a mandrel which serves to guide the article to the rolls. A sleeve shrouds the working surface of the rolls for safety.