Abstract: The rotatable cutting tool includes a cutting portion extending from the front end and a mounting portion extending from the rear end. The cutting portion includes a front end face surface and a peripheral surface extending from the front end face surface towards the mounting portion. The peripheral surface includes first helical flutes extending from the front end to a first helical flute rear end and second helical flutes extending from a second helical flute front end to a second helical flute rear end. The first helical flutes are helically aligned about the longitudinal axis and form a first helix angle. The second helical flutes are helically aligned about the longitudinal axis and form a second helix angle. The first helix angle decreases in absolute value away from the front end and/or that the second helix angle increases in absolute value away from the front end.

Abstract: The rotatable cutting tool includes a cutting portion extending from the front end and a mounting portion extending from the rear end. The cutting portion includes a front end face surface and a peripheral surface extending from the front end face surface towards the mounting portion. The peripheral surface includes first helical flutes extending from the front end to a first helical flute rear end and second helical flutes extending from a second helical flute front end to a second helical flute rear end. The first helical flutes are helically aligned about the longitudinal axis and form a first helix angle. The second helical flutes are helically aligned about the longitudinal axis and form a second helix angle. The first helix angle decreases in absolute value away from the front end and/or that the second helix angle increases in absolute value away from the front end.

Abstract: A tool for machining a stacked material workpiece includes a tool body having one or more helical flutes extending to a forward end of the tool body. Each helical flute has a width defined by a first cutting edge and a second edge, a surface of the flute adjacent the first cutting edge facing the forward end of the tool body and a surface of the flute adjacent the second edge facing away from the forward end of the tool body. Each helical flute can include a first portion having a first negative pitch angle and a second portion having a second negative pitch angle different from the first negative pitch angle, the first portion extending from the forward end of the tool body to the second portion. The tool has only negative pitch angles. A method for machining a stacked material is also disclosed.

Abstract: A tool for machining a stacked material workpiece includes a tool body having one or more helical flutes extending to a forward end of the tool body. Each helical flute has a width defined by a first cutting edge and a second edge, a surface of the flute adjacent the first cutting edge facing the forward end of the tool body and a surface of the flute adjacent the second edge facing away from the forward end of the tool body. Each helical flute can include a first portion having a first negative pitch angle and a second portion having a second negative pitch angle different from the first negative pitch angle, the first portion extending from the forward end of the tool body to the second portion. The tool has only negative pitch angles. A method for machining a stacked material is also disclosed.