As a lawyer, I can say that you want to avoid us at all costs, because it generally costs all. BUT - if this guy is determined to shaft you, at least you can smear his reputation as loudly and publicly as possible - that's not a good thing for a businessman, and powerful incentive for him to meet his end of the bargain. SO, the idea of sending him a letter certified mail, return receipt requested (and you can specify that only HE can sign for it) is a very good one. In that letter you need to set out the details of the deal, what you paid and when, how many times you have contacted him, what was said, and your inability to contact him lately despite several attempts. Finish up with "I understand that you have had difficulties completing the knives, but at this point, after waiting eight years, in order to preserve my legal rights I am alerting you that I expect you to furnish the items that I have paid for within the next six months."
At the bottom of the letter that you send, write "sent via United States Post, certified mail number [fill in number]" and sign it. Keep a copy of the letter, and the green card that you get back with his signature.
THEN, if he still won't pony up, you can sue him - you can go to small claims court if the value is under $3,000, I think, and not need a lawyer. This is a formality, because the real weapon you have is that you can write to every knife forum and every knife magazine, listing your lawsuit and the reason for it. Whining is whining, but a lawsuit is NEWS. THAT is the kind of publicity NO ONE wants, and unless he publicly makes good with you it should hurt pretty bad. Especially if everyone on this forum then writes a letter saying "wow, I was going to order a knife from you, but after hearing about the lawsuit I guess I will go to [insert other maker here] instead."
Or we could just pound him.
Good Luck!
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The beatings will continue until morale improves.