Hey Sean! What steels do you use for your knives?
I've been asked this question several times in the past few months, and normally I would just say what type of steel was being used for the knife the customer was asking about. Now though, I'd like to go a bit more in-depth as to why I use specific steels for some knives, and why I don't use them for others.
I've used a handful of steels that range from high carbon low alloy steels to high alloy, high carbon stainless steels, all depending on the kind of knife the user is asking for.
If I was asked to make a collector's piece or hunting knife that needs a non-reflective, antique looking finish, and still be able to hold a fine edge, I would use a high carbon steel like AISI 1095 or O1 tool steel. This was the case for my first batch of knives, and these are good, tough steels.
If I was asked to make a chef knife that's constantly exposed to wet and acidic environments, a high carbon steel will not do. It will rust and pit if not cared for properly, and can sometimes leave black marks on your food from the blade oxidation. I'd use a high carbon stainless steel because it doesn't react to the environment as readily as a high carbon steel would. I've used high carbon steels like AEB-L and 440C to make these knives.
There was a rumor going around that high carbon stainless steels don't hold a sharp edge, and if they were tempered to a high hardness, they would snap easily. This is simply not the case anymore. Back when the information regarding cryogenic tempering was not as popular as it is today, a knifemaker had no way of knowing that a soak in freezing cryogenic temperatures would reduce the amount of fragile, metastable retained austenite in a high carbon stainless steel like 440C. Now that this information is more widely available, it is the responsibility of the knifemaker to make sure all their blades are heat treated and tempered according to the widely available and accessible procedure provided by the steel manufacturer. There is no sensible secret formula to making a bad steel stronger, no unique way of forging a leaf spring to get it hard enough to cut steel pipes, and no secret quench that can outperform industry standards.
Looking at blade steels is nice and all, but it's not the bottom line for quality blades. What's more important is the heat treatment, cryogenic treatment (if applicable to the steel), and temper soak. A properly heat treated and tempered 1095 will outperform a poorly heat treated and tempered D2. Ultimately it's the responsibility of custom makers to be honest and provide you with the best steels for each custom knife, treated to the best possible performance standards for the steel.
I want to show you the finest knives inspired by Filipino culture, and I hope this gives you a little insight into what makes a high-performance custom knife. Sign up to my newsletter for updates, giveaways, and more information in what makes a high-performance knife!
*Disclaimer: All of this is information based on my personal experience as a knifemaker, and reference materials I studied while learning how to work with these materials. It should not in itself be cited as a significant reference material. I urge and encourage you to do your own research and reading from published books and scholarly articles for a more in-depth study regarding this subject.
Some quick terminology:
AISI - Stands for "American Iron and Steel Institute." An abbreviation used to indicate the numerical classification standard of the steel. This is the standard I use to classify the steels I use unless otherwise specified.
Cryogenic treatment - Treating workpieces to freezing temperatures that range from -70C (shallow cryogenic treatment) to -196C (deep cryogenic treatment)
High carbon stainless steel - An alloy steel with more than .5% carbon and a minimum of 10.5% chromium. This is, generally speaking, a stain resistant steel that can be hardened.
High carbon steel - A steel with more than .5% carbon. This is, generally speaking, a steel that can be hardened.
Leaf Spring - A spring made of stacked flat bars normally used in car suspension.