Abstract: A joint structure, constituting a camshaft, of a metallic tubular member and metallic annular cam defining parts, the annular parts being joined to the outer periphery of the tubular member. Each of the annular parts has around its inner periphery at least one serrated portion which cuts into the outer periphery of the tubular member when they are joined, the annular part also having a planar portion facing another portion of the tubular member in such a manner that substantially no pressure is exerted on the planar portion of the annular part.

Abstract: A joint structure of a metallic tubular member and metallic annular parts, the annular parts being joined to the outer periphery of the tubular member as in a camshaft. Each of the annular parts has around its inner periphery at least one serrated portion which cuts into the outer periphery of the tubular member when they are joined, the annular part also having a planar portion facing another portion of the tubular member in such a manner that substantially no pressure is exerted on the planar portion of the annular part.A method of making such structure involves positioning of the tubular member is required in relation to the annular parts, as by use of a split die, and then forcing into the tubular member a pressing member to expand the tubular member so that the serrated portions cut into the outer periphery of the tubular member.

Abstract: A method of producing an insert for the combustion chamber of a diesel engine having an oblique injection port comprising inserting a cylindrical work blank into a die, then cold- or hot-compressing such cylindrical work blank between a punch and counter-punch to form a compressed center-recessed shape, forming an oblique recess in at least one side of the bottom of the center recess of said shape at such an end position as to correspond to the injection port to be formed, and then developing a hole in said oblique recess in conformity with the configuration and extent thereof.