About as low tech as it gets, even for modern knives that are pretty high tech in how they're made.
But it's entirely possible for a person to make a knife with nothing but tools they can make by hand, with no need for anything other than rocks as tools. I've done it, and it isn't like I'm some kind of super genius.
You can make slightly more high tech tools if you want, and make metal knives. The caveat to that is that you have to know how to identify sources for the metal in the first place, unlike stone tools where you can figure it out by banging rocks together until you find some that make sharp edges. But making an oven that can turn out low-grade materials is realistic for a single person to do.
But a knife, in its essence is just an inclined plane done to a very fine degree. Doesn't get any more low tech than that. Mind you, there's plenty of complexity involved in all of the basic machines like inclined planes, but that's more about understanding them than using them or making them.
Knives are mankind's most important tool. They were among our first tools, and it can be argued that they were our first manufactured tools. And we still use them regularly. Some of us use them every day, multiple times a day.
That's a lasting technology in every degree of refinement.
Honestly, kind of mind blowing even thinking of them as a technology, they're so ubiquitous. I use a knife a minimum of 10 times a day, and that's just in the kitchen, not including opening mail, packages, small medical stuff, and a ton more uses. Holy shit, where would we be without those inclined edges?
Awesome comment to read at 430 in the morning. Thank you
Also knives and woodworking. Blades are what made the great Japanese temples. Lots of sharp steel and a dream. It is amazing what Japanese blacksmiths can do with steel, and the excellent performance they can achieve with them.
The knife is a technology. It was invented by a person. And that person was not the same species as us. The knife has been around longer than Homo Sapiens.
I've commented on this before, but it reminds me of the mortise and tenon joint. The oldest intact wooden structure on Earth is held together with mortise and tenon joints. The man who built it never wrote his name down, because writing hadn't been invented yet. He never rode a horse, because animal husbandry hadn't been invented yet. He used stone tools, because copper smelting hadn't been invented yet. In the present day, Festool sells a tool to make mortises called the Domino which they still hold a patent on. We're still actively developing this technology which has been with us slightly longer than civilization has.