Perhaps I'm wrong, but wasn't the original point being made that the OP couldn't find an oval mandrel with the required ratios for the oval. 'Oval' is a pretty generic term..
Thom, you read correctly. This device is for producing odd ratio oval
mandrels. Many jewelers have access to, or a friend with machining
capabilities, so this is an option.
To get the best weight from some stones that I facet, making a bezel
or prong setting from scratch, fabricating or revamping and existing
setting to fit these oval shapes, gets old really fast.
Admittedly this is a special purpose device, but my hope was to show
the folks how I am dealing with the issue.
Thanks for the compliment.