Method and apparatus for slotting tubular steel

A method for slotting a round tubular workpiece, said method comprising the steps of:

• (a) disposing a sacrificial liner adjacent the cylindrical inner surface of the tubular;
• (b) plunging one or more rotating blades radially through the wall of the tubular and partially into the sacrificial liner;
• and
• (c) removing the sacrificial liner from the tubular.

A method for cutting a slot through the wall of a ductile metal workpiece, said method comprising the step of plunging a rotating blade radially through the wall of the workpiece, wherein:

• (a) the rotating blade is a blade comprising a circular main blade body having a first face and a second face, plus a plurality of cutting teeth arrayed around the circumference of the main blade body, wherein at least two of the cutting teeth are thinned teeth, having a substantially uniform thickness less than the thickness of the main blade body;
• each thinned tooth has an inner face and an outer face, with each outer tooth face being flush with either the first or second face of the main blade body;
• and the face of the main blade body with which the outer faces of the thinned teeth are flush, alternates between said first and second faces from one thinned tooth to the next;
• (b) the depth of slot cut by the blade is at least ten time the thickness of the main blade body.