How do you handle the heat treating of the Ricasso, Ricasso and handle junction and the tang? The type of knives I'm asking about with this are a hunter style, a Bowie style and a JS test knife. I suspect the exact techniques are different for each. What hardness should one make each of those three areas? Using 1080 or 5160. How do you handle this differently if making a full tang or hidden tang knife?
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How do you handle the heat treating of the Ricasso, Ricasso and handle junction and the tang? The type of knives I'm asking about with this are a hunter style, a Bowie style and a JS test knife. I suspect the exact techniques are different for each. What hardness should one make each of those three areas? Using 1080 or 5160. How do you handle this differently if making a full tang or hidden tang knife?
John you will find a prevailing attitude among many smiths that these parts should be left dead soft, this is mostly a result of a lack of in-depth understanding of yield points and plastic vs. elastic strain systems. Needless to say, I do not share this viewpoint. The area around the ricasso and tang juncture can be drawn back a bit more than the blade but the danger of this critical point bending is greater than it breaking, and a blade that bends at the handle/blade juncture is not a very useful one. Add to this the effects of creep/strain failure when you have to straighten such a blade and the idea of a properly heat treated ricasso start to look even more appealing.
It is only the last 1/3 or 1/2 of the tang, especially with threads, that I leave soft, as it is well supported inside the handle. But I personally heat treat the ricasso guard area the same as the rest of the blade since it is where the guard will set that I take my HRC readings to evaluate my heat treat. Then, if I really think it is necessary, I will draw the area back more. I am pretty confident that if folks have experienced brittle type blade failures in this area it is the result of other contributing factors such as stress risers from improperly sharp corners and other poor geometry such as insufficient dimensions to handle the load.
On the test knife I think you should rely on the geometry to handle much of the load. A personal pet peeve of mine is a test knife that kinks to a tight 90 at the ricasso/tang juncture, and I inform any who test under my supervision that I will not count any such bend towards the 90 degrees they need to reach with the heat treated blade; I need to see the ricasso/plunge cut area go to 90, not the handle. At journeyman these rules still apply but I am less critical of the handle bends a bit. But I personally feel a Masters test knife should not suffer from this issue as one wishing to be called a "Master" should have a complete enough grasp of both heat treatment and geometry to avoid this.
"One test is worth 1000 'expert' opinions" Riehle Testing Machines Co.
Kevin, Thank you very much for your answer!
