A replacement blade for the Lie-Nielsen #4 & 5 planes, made with the same care and to the same standards as the rest of their products. All the blades are cryogenically treated A-2 Tool Steel. Note Lie-Nielsen blades are 3.2mm(1/8") thick as they prefer to use as thick a blade as possible. When up-grading a Record or Stanley plane if the blade is too thick, the Chipbreaker Screw may not be long enough to install the Chipbreaker, we have available a long cap screw. Most important the mouth opening may not be large enough to allow the blade, or a shaving, to pass so a little fettling may be necessary.