Looks like it locks right in the hand holding it.
What do you do to get the black finish that stays put? I've quenched in used motor oil, but that will wear off eventually, and sometimes that is alright provided the user kept the steel rust free.
I gun blue it, with a different twist. First I heat it up a bit, not enough to take off the temper, then I clean it really good and use Brass bluing on it several times, washing it off and using 0000 steel wool, then I use cold gun blue repeating the process as I do with the brass blue at least 5 times, usually more.. I've had knives done that way over 10 years and they still looks as good as the day I done them. Just keep them oiled.