I have two sets of knives that will fit a 6" Delta jointer. One set is marked "Delta", "Made in Germany", "HSS 18". The other set is unmarked, but appears to be the same dimension. I also have a 7th knife, marked "Craftsman", "6 1/8"", 9 2293 18112.
All knives are in excellent shape,and in fact, don't think they have ever been used, but can't swear to it. They are sharp, but not honed and razor sharp. I bought them with a bunch of stuff at an auction. I don't have a 6" jointer so can't use them
$25 for all seven knives plus shipping. Email if interested.