Star Mandrel... why?

[Green Monster]

Who uses a Star Mandrel (8 point) and why? What does it do that a smooth mandrel doesn't? (other than cut into the inside of the ring.

[Dennis]

I have an octagonal collet mandrel, Which came as one of a cheap set from Proops. It is meant to perfect collets for octagonal stones, but I have never used it.
Even so, the Proops set is very good value. Dennis

[Green Monster]

ah, yes, would make more sense as it is a small diameter, perhaps the "points" give a sharper corner than a smooth surface would do.
cheers

[EmmaC]

The different shaped mandrels are also quite useful for wire working to get a good even shape.