The body of these planes are ribbed to ensure strength and rigidity. The machined faces of the frog bed sit firmly onto similar machined faces on the body of the plane and then fastened in position by two screws. This positive positioning helps prevent chattering. The cut iron is made of high carbon steel, hardened and tempered under scientific control for accuracy and uniformity. Handle and knob are hardwood. This is the #4 traditional smooth plane — a plane that can be used for a variety of work.