Kakuri blades are heavy high carbon steel tempered to Rockwell c60- c63 and sharpened to a razor edge. The easily adjustable chip breaker is held firmly in place with a thumbscrew. The blades can be easily sharpened or inexpensively replaced. This Extra blade is for use with our 1¬" Mini Smoothing Plane which will have a maximum cutting width of 1", and the 30ø, 45ø & 60ø Chamfer Plane which will cut chamfers up to 3/4" in width. (Similar plane blade pictured).