a mold for forming an article having one or more substantial radial protrusions . the mold includes a core movable along a molding axis , a stripper ring movable a limited distance along one set of guide rods with axes parallel to the molding axis , a split ring having segments movable adjacent to the stripper ring for the limited distance and movable relative to the stripper ring on a second set of guide rods at an angle to the molding axis , and a cavity . the article is removable from the mold when the core is moved away from the cavity , the stripper ring is moved its limited distance , and the split ring segments are moved with the stripper ring and then relative to the stripper ring at an angle to the molding axis .