Here are some notes on Helle knives:
They are hand assembled in the remote village of Holmedal, Norway, population 500. The firm was established in 1932 by two brothers, and continues a tradition of fine materials and careful hand work.
Most Helle blades are made of triple laminate stainless steel, a sandwich of tough stainless panels with a core of high carbon steel. It is especially made for Helle, and does not correspond to any of the standard types of steel. High carbon steel is tougher than stainless, easier to sharpen and holds a superior edge. For the technically minded, the composition of the high carbon steel core is:
Carbon -0.67%, Silicon -0.70%, Sulphur -0.002%, Phosphorous -0.19%, Manganese 0.44%, Nickel -0.28%, Chromium -0.28%, Molybdenum -0.52%.
The high carbon steel core is hardened to 58-59 HRC (Rockwell Scale). This is the harder part of the blade that holds the edge.
The outside layers are tough 18/8 stainless, 18% chromium and 8% nickel. Together, this makes a blade that can be sharpened to a very fine razor edge, and yet is not brittle. It is also easier to re-sharpen than conventional knives because much of the steel being removed (the outer panels) is softer than standard cutlery steel. This type of blade will bend long before it would break.
Most Helle blades also have the distinctive Scandinavian grind. This is a wide, flat bevel that runs to the edge. There is no secondary bevel as on other knives. This results in an exceptionally keen edge that is easy to sharpen without jigs or other gadgets. Simply lay the bevel flat on the hone.