1-22-05 Here is the blade I am engraving. You can see at the top, the original drawing, under that the first scale pattern which I found to be entirely unacceptable. Paper drawings are great but until you hold a pattern or mock up in your hand, you never know what you are going to get. Then the second pattern with a better handle size and then the actual blade that came out just a bit larger. Bolsters from 416ss have been rough profiled and drilled. You can’t see it in this picture because of the reflection but this knife has already been engraved. The bolsters are normally done later but I got a start on them early.

1-22-05 This is an EvenHeat heat treating furnace.It will get up to 2250 degrees that I know for a fact when I programmed it wrong and I burnt up a knife blade. I haven’t programmed it yet for the 154CM temps so you can see there is an error message on the LED read out. It’s 29 degrees in the garage today so it will take a bit to get going. The foil pouch rests on a couple of fire bricks inside the furnace.

1-22-05 These are the large aluminum quench plates I use to quench the knife just out of the furnace. When the knife has soaked at 1950 degrees for 20 minutes, I take it out with tongs you see just to the right while wearing welding gloves. The knife stays in the foil pouch and is placed on the aluminum and another aluminum plate is placed on top of the knife and pressed down. This take the heat out of the knife very quickly. In fact you can hold the knife in your hand after just a minute or so after being pressed in between the plates. I have just about three seconds to get the knife from the oven, to the plates and to get it cooled below 1000 degrees. After quenching, I test the hardness of the blade to make sure the heat treat came out as it should. The is it off to the cyro to soak over night.

1-22-05 This is a liquid nitrogen dewar and is mostly used to keep cattle seamen or biological samples frozen at minus 300 degrees F. This 30liter container will keep liquid nitrogen for approximately 6 weeks before it evaporates away. In this picture, I have just lowered the knife into the liquid by a metal cable and capped the container. The cap has a small hole to vent escaping gas. You can see a plume of escaping gas here. The knife, when it is first lowered into the nitrogen causes it to boil and bubble furiously. You can feel it shake around quite a bit until it cools off to minus 300 in a couple of minutes. Until that happens, it spouts this gas at a pretty good clip. It’s the funnest part of the heat treat. I’ll leave it for at least 8 or more hours before we do the temper treatment. Cryo treatment will increase the edge holding on high alloy steels like this by 30%. It’s worth doing. After the cryo, the RC hardness has increased by 1.5 on the average. Cryo basically helps convert any remaining austenite to martinsite. This is a good thing. After the cryo, the blade gets baked at 400 degrees or so twice for a couple hours to soften it slightly. This is called the temper. The knife is basically too hard and brittle to use after the heat treat and cryo so it has to be softened up slightly. Back to the furnace for 2 rounds of 400 degrees. Then it will be ready to continue.