It's one of the goldsmith's correlations of Murphy's Law - no
matter what oval mandrel you have, your stone will be of a
Where does the Murphy lives? Under your bench!
With that observation, since we on the subject of making ovals, I
want to recommend my DVD “Coronet Cluster”
The design is based on 4 ovals, which are fabricated to fit each
other very tightly. If anybody having troubles of fabricating ovals
to precise specifications, after working through the DVD it will be a
walk in a park.
In more general terms, no mandrel was ever intended to be used as
something that conforms exactly. A bezel is formed by utilizing
different areas of a mandrel. Bezel block is where exact form is
achieved, and if particular proportion and/or sizes are not
available, than techniques demonstrated on the DVD, can be used to
fabricate required shapes.