Do not attempt to tighten a flush set stone by hammering on the metal surface, forcing the metal over the stone. This causes a dip in the surface surrounding the stone, resulting in an unsatisfactory appearance. If you use a hammer and punch (or hammer handpiece on your flex-shaft) be certain to hold the punch at a 45 degree angle to the metal surface and tap lightly ONLY on the edge of the metal, until it is worked down over the stone.
To secure a Flush Set stone you only need to burnish the top edge of the metal down onto the stone.
~Brad