I think it comes down to whether you are trying to fool people or not.
Custom gunsmiths often do nothing more than stone a trigger, or work over a pre-existing design. Very few of them actualy build guns from scratch. So there is at least one trade where it isn't considered all that strange to call oneself the equivalent of a Knifemaker, while only specializing on one area. Cabinetmaker is another. heck some people who don't make cabinets at all, but maybe chairs call themselves that.
Now let's talk about great knifemakers, say the guys who make Katana. They often don't make all the parts (though the blade seems to be the biggie) They don't polish the blade. The idea that one has to do every part of a specific project oneself in order to claim credit can at times mean that the craft either isn't very complex or advanced. You could be an aircraft designer, but there isn't any hope you will ever bring out your own Boeing 777. No one person can handle all that work. Maybe our craft would be more advanced if everyone wasn't in fact capable of doing everything from make their own forge to doing their own website and sales. Maybe that says something bad about us, as well as something good.
But obviously if you do something like put handles on knives, and say grind out the original blademaker's name, and claim credit for something you didn't do, that's a dark hole to fall into.
