User, Yes we did change steels in 1980. Up until that time we had pioneered and used 440C as a replacement for file steel. My Father had felt that the 440C was rusting too much and wanted to know if we could get 58RC out of a steel that had less carbon. We switched to 425 Modified. It had a little over half the carbon that 440C did. This also allowed us to fineblank parts and helped with folder action with the accuracy in fineblanking.
In 94 we switched to 420HC. The HC stands for High Carbon, and is a relative term. Standard 420 is used for kitchen knives everywhere. The HC version is closer to the 425M and we get 57.5-58 RC consistently. Paul Bos has been a help there. This gives a nice mix of edge retention and corrossion resistance.
As to grinds...we totally changed our grinding in the 80's. We went from a semi hollow with a flat edging operation to a full hollow. It meant that there was not as much abuse resisting thickness along the edge but the new full hollow would cut better and hold an edge longer and be easier to resharpen.
In 2000 we redid this edge geometry again. Our testing said that edge geometry played a larger role in edge retention then blade material or hardness (when all things were fairly close). Edge geometry plays a huge role in resharpenability. Edge 2000, which we have now changed to Edge 2X keeps a very consistent edge thickness and a consistent edge grind thickness (bevel). We are looking for a bevel angle of 13-17 degrees on each side for an included angle of around 30 degrees.
One other point. The harder the steel the sharper you should be able to get your knife. When steel is sharpened to a fine edge it is very thin. Harder steels support themselves being thin better that softer steels so I have found that the knives we harden to 60 RC feel sharper to me. These edges being so fine also have a very high surface area to internal density ratio and many times edges are lost due to corrossion than use.
Sorry if I got a little long winded here.
User...you are welcome to send in your two knives as well for a free sharpen...I'll have to stay off this thread so Joe can hit his sharpening budget...
