Abstract: Shown and described is an on-edge cutting insert for milling cutters in the form of a flat six-sided block having two parallel major faces which are seating and clearance faces, and two opposed edge surfaces which are rake faces which intersect at least one major face of the flat block to form two parallel cutting edges therewith, and two other opposed edge surfaces which are recessed centrally of their major dimension to form sideward projections of the cutting edges at the corners of the major faces.The recesses accommodate the sideward projections of the cutting edges of the adjacent inserts in an interfitting array of inserts along a single chip gullet in which the several inserts sweep contiguous concentric segments of a more extensive uninterrupted cutting path.

Abstract: A cutting tooth is carried on the outer end portion of a shaft which is eccentrically mounted within a power-rotated boring bar and which may be selectively turned within the bar to enable the tooth to be adjusted between an inactive retracted position and an active cutting position. By sliding the shaft in one direction, serrated rings mounted on the outer end portion of the shaft and within the outer end portion of the bar may be uncoupled to permit turning of the shaft. When the shaft is slid in the opposite direction, the rings are recoupled to establish a torsionally stiff rotational drive to the tooth by way of the outer end portions of the bar and the shaft. Turning of the shaft to adjust the tooth to its cutting position also effects outward adjustment of support pads for maintaining the outer end portion of the bar in a stable radial position during the boring operation.