In order to saw the coin you're going to need a small but sturdy clamp, a lamp with a bendable neck to make it more obvious where the saw is going, and a saw with 4/0 blades. These blades are excellent for cutting through metal, and are small enough to protect the intricate details of the coin. Because they are so small, breakage isn't uncommon, so have a few handy.

Attach the clamp to a sturdy surface and put the coin facing up between the two. Take the saw and attach the blade to only one end. Then slide the other end of the blade through one of the holes you drilled (you most likely won't be doing any sawing with the hole you drilled to attach the coin to a necklace). Secure the other end of the blade back to the saw so that the saw is ready to be used.

Slowly start cutting through the metal, forming the rough shape against the pattern on the coin. Start taking out small segments so you can give your saw more room to maneuver. Each time you go from one area split by a bar to another, you need to remove the blade from the saw and reattach it like previously. This part is easily the longest part. Depending on the complexity of the coin it can take anywhere from 30 minutes to 2 hours.

Don't be too worried about the shape appearing very rough, because unless you're a master with a saw, you're going to need to file some points down.