Norb - I'm sorry you haven't received a reply by now. It looks as though this forum can't offer you much help on your question. I have 3 of the 7610s and the bit collar is broken on two and missing on the 3rd. Yes, they have stood the test of time. (I have other "newer" Dewalt & Bosch 1/2" routers) If you can't find the parts you need, it may be time to upgrade. I cruise the flea markets and pawn shops when I can and often see tools that would be good for parts but their asking price is rediculous. But, they are out there. You just have to get out and be adventurous. Let us know what you come up with.
You mentioned that you are a machinist - do you have the means to make a nut yourself ?
You mentioned that you are a machinist - do you have the means to make a nut yourself ?