Neckrings...

Made from MDF and cut on a bandsaw.
The entire bandsaw was angled to achieve the chamfered angle on the edge
- not something I would recommend. Cutting neckings with a router is probably the best bet.

The holes around the inside edge were drilled before the inner circle was cut out.
Each hole comprises of three small holes that run into each other. Pilot holes were drilled first to
stop the drillbit from skipping into the adjacent holes.