What's id really like to see is the evidence for the majority of these claims. Every thread I've ever seen as "definitive proof" ultimately comes down to hearsay or shotty "evidence" from somebody's brother's cousin's friend Jed.
I don't have a dog in this fight, other than the few examples of Bark River I've seen having been extremely wellmade, and the Marbles I have from the Stewart era is fantastic. I have seen Mike Stewart interact with people on FB and from what I can tell he isn't an outright bad person.
Obviously, this is all anecdotal!
The fellow who mentioned the steel deceptions is Anthony Lombardo posting as BladeandBarrel here, scroll to post #268 -
www.bladeforums.com/threads/bark-river-has-taken-16-000-of-my-money.585934/page-14#post-6025093 .
He actually worked for BlackJack. There have been other posts in support of this by other BlackJack employees over the years, but I don't recall their user names, and don't care to dig through 1000's of posts.
As to Stewart admitting it? That post was on the old defunct Knifeforums, where he ran the Marbles forum. People used to ask about old BlackJacks all the time, and one question was about steel types used. He admitted that toward the end, they used what was handy, whether it was older blades, different carbon steels (albeit ones that BlackJack was known for using), etc....
This didn't cause a fuss because - a) It was in discussion of simpler steels, not any specialized ones. b) It was in discussion of a different era in knife making. In the mid to late 90's when those knives were made, there was no social media, aside from maybe rec.knives, which very few knew about. You had to wait months for maybe a small announcement in a magazine about a steel change, and if one happened most people just shrugged, and hoped that yours was in a steel you liked. So that is why Stewart probably felt safe talking about it.
Now you can tell the world in 10 seconds about problems, so there is no excuse for such things.
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As for Stewart's response to this guy's problem. It's laughable. He's playing the industry giant angle that he does sometimes (When he's down, it's the "hat in hand nice guy". When he's up, the arrogance starts).
A little thing like changing the steel may only seem like a savings of a couple of bucks, but you stretch that across even a portion 40,000 knives, over multiple years, it's huge money in this industry. Also if he is actually doing it, it's a safe con. The tests to conclusively figure it out are over the cost of the knife, and you'd need to test multiples across a bunch of different things, to prove it wasn't just a bad batch.
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Again, enjoy the knives, but never trust Mike Stewart. There are reasons why guys like Fisk, Reeve, Maringer, Applegate, Becker, Cargill, Lovestrand, etc...., etc..... have nothing nice to say about him. They didn't just pluck his name from the sky.