Heat exchanger fin roll

A pair of heat exchanger fin forming rolls, each comprising a plurality of gear-like discs having teeth spaced uniformly around the periphery thereof, said rolls being arranged on generally spaced parallel axes so that the teeth of the discs on one roll mesh with the teeth on the discs of the other roll when the rolls are rotated in one direction, each tooth terminating in a generally rounded tip at the radially outer end thereof and being connected with the adjacent teeth by a generally rounded crotch of greater curvature than the tip, each tooth having a leading face and a trailing face relative to said direction of rotation, said faces being beveled in a direction transversely of the plane of the disc so that each of said faces has circumferentially spaced inner and outer edges, said outer edges defining cutting edges on the opposite faces of the discs, said beveled faces of the teeth on the two sets of discs being in generally parallel overlapping relation when rotated into meshing relation, the leading face of each tooth being beveled from a point within the adjacent crotch in a direction radially outwardly through the tip of the tooth, the trailing face of each tooth being beveled from a point within the crotch to a point adjacent, but spaced radially inwardly from, the tip of the tooth, the radially inner end of the cutting edge of each trailing face terminating closer to the vertex of said crotch than the radially inner end of the cutting edge of each leading face.