Blade pan question

[miked32]

What does that mean. It was first scratched into blade pans?
I’ve read at one point they stamped it with a X before the heat treatment. Then after. I was just curious what the first sentence in the pic was referring to.

Thank you

[Mumbleypeg]

Blades are placed into a pan, the pan is pushed into a furnace where it (and the blades it contains) is heated to the desired temperature. The pan is then pulled out of the furnace and either air or oil quenched, depending on the steel. They marked an X on the pan so they knew how many times it had been through the process. I recommend watching this factory tour video. You’ll see the blade tempering about a minute into the video. https://youtu.be/DskCh5-L878?si=GsSc_VLPVS0Z_9JI

Case Brothers Cutlery originated the marketing of the two X’s (XX), touting that the blades were double-tempered. They registered the “XX” and “Tested” trademarks and started stamping it on knife blades. (It was never used singularly to mark blades after they were tempered - it’s not how the process works. Blades are stamped before they are tempered/hardened). When Case Brothers Cutlery went bankrupt, W.R. Case and Sons bought the rights to those trademarks from Case Brothers. Many do not know they were two entirely different companies, and competitors. Russ Case was a salesman for Case Brothers (owned by his uncles) before leaving to start W.R. Case & Son. He knew the value of the XX trademark, so when he got the chance he bought the rights to use it.

Ken

[Modern Slip Joints]

Your wording could be better. Simple tool steels like 1085 and 1095 blade alloys are first heated very hot then quenched making them too hard and brittle. The pan got its first X so it would be obvious only that first step was done. In the second step, tempering, the pan is heated to a lower temperature then quenched again. The pan got its second X to mark its contents hardened and tempered. Tempering makes the blades less hard and much stronger. In other words after tempering they can spring back from a little flex rather than snap. It also makes them easier to finish, polish and sharpen.

[Mumbleypeg]

Agree, I’m no author and I don’t play one on television either. My wording choice here was taken from the OP quesion and the wording from the box he referenced. Here’s an explanation from an old Case Collector newsletter.

Ken