User:Stever/Projects/rondeldagger: Difference between revisions

With most of the parts now made it was time for a test assembly. The first stage of the process was "burn-in" the tang of the blade by heating it up to about 400C and then pushing the handle over it until the heat burns the opening wide enough for the tang to fit snugly. This had to be done before the final hardening of the blade as otherwise the heat from this process would ruin the temper of the blade and make it impossible to sharpen properly.

 

 

New tank fabricated it was back to the forge for the blade to be normalized and straightened (and re-normalized, and re-straightened, and re-normalized and..... you get the idea). Once the blade was stable and relieved of all internal stresses it was put through a process of grain refining which changes the structure of the metal to adjust the size of the crystal grains within it. Doing this maximizes the strength and toughness that can be achieved without lowering the final hardness too much. In the final forging process the blade was then heated to 900C, held at that temperature for a couple of minutes, and then plunged into the oil. After hardening the blade was cleaned up and the scale removed using the [[Tools/polishingwheel|buffing wheel]] before hardness testing. Testing it with the [[Tools/hardnesstester|ultrasonic hardness tester]] revealed a final surface hardness of around 53HRC which is a good hardness for this type of blade being hard enough to take a good edge but still tough enough to withstand hard use.