there is a gentleman who works in an accredited lab that does steel testing and analysis as his profession, that is into knives, and has been rockwell hardness testing knives and created a database. very professional, and way over my head for alot of it. I understand the rockwell stuff, but for steel that can be destructively tested, he does some very complex testing and analysis. he is the one i saw talking about shiro doing custom heat treats by batch, so i believe that to be the case, but not sure if they also do it for their more affordable pieces. I imagine they do, because even the "affordable" options are still very expensive.I'm unfamiliar with that "custom heat treats" protocol, but my experience with Shiro is that they do an excellent job on every blade steel I have or have had including M390, Vanax 37, Elmax, S30V, Cromax, and 440C. No issues with with chipping or edge retention and good ease of sharpening for each variety.
here is the database, it is growing every day.
Steel Hardness Lab | Rockwell Hardness Testing Database
Independent Rockwell hardness testing of knife steels. Professional-grade testing by certified metallurgical technicians using calibrated, ASTM E18-compliant equipment.
here is the authors reddit profile which is good reading for steel information. he posts more context here almost daily
He is now in communication with Metal Complex(not my favorite content creator, but his reach is vast), and MC is trying to get him some contacts in the industry to hopefully get alot more samples for testing. currently, he offers paid testing if you want to send blades in for testing, they then get added to the database for the community.
As far as his Shiro testing goes, which has been limited thus far, one of their Magnacut samples tested 64.6hrc! One of their s90v samples testing 62.8! Fantastic results, both are at the tippy top end of the "desired" spectrum. By comparison, a Hinderer Magnacut sample has been tested all the way down at 60.8, which for transparency is a few years old and they have since improved their process and now arrive in the 62 range. Microtech has been all the way down in the 58s, absolutely embarrassing. Not many s90v samples have been tested but CJRB's sample tested in the 60s. When you take into consideration that single points can provide exponential performance increase/decrease, you begin to understand how impressive Shiro's results are. One of the few "production" companies that you can rely on their steel being treated properly, another is Spyderco. There are some stomach churning results in there for alot of people, so make a drink if you need to LOL

