Learn Gemivision Maxtrix. Its a powerful CAD modeling tool geared toward Jewelry design. We can even make things that are insanely difficult or impossible by hand. The software itself is serious and measures material costs, but in the end you can use something cheap, like brass or zinc or something cheap.
After you model the item you can scale it obviously and for rings this software will go us on fitting size if you want.
Then you'll need a jewelry 3D printer. Its a small printer with an extremely high resolution for printing small detailed objects, and it does it in wax.
Why wax ? Cause that is a part of the cast moldind process.
Cast mold the first one in say, bronze. Then you can create molds from that, unless its a complexed shape, then use wax again.
If you learn this, order the fake diamonds at your desired scaling. Matrix will have diamonds to scale so order the ones you used.
You'll have to insert the diamods by hand, so don't go too crazy cause you'll want to fulfill orders. If you can get bulk deals, then you'll want to contact a precision company. They basically mass produce parts or whatever you throw at them, and for a price they will produce thousands of what you give them. The CAD file itself would be a bonus. Before making a big deal, tell them you'll have to check your resources. Then asap, get a price quote from the production company and how long it'll take. They are rather quick and will show up with your order in boxes ready for you to count.
From there you'll want to get the items plated. Chrome or Rodium on nickle. Or Gold even. This increases the value of the item so you'll have to jack the price.
People want to look fancy. Let them have it for 10-20 bucks depending.
