THE SETTING OF DIAMONDS

Matamata Record, Volume II, Issue 77, 11 April 1918, Page 4

THE SETTING OF DIAMONDS

Setting diamonds is one of the troublesome jobs that fall to the lot of a machinist or grn.dcr at more or less frequent intervals. The method in general use consists of drilling a hole for the diamond, and after placing it within the hole, closing the metal in about the stone as far as possible, and then pouring molten spelter to fix tlu* diamond in place. The chief objection to this method is that the spelter will not flow evenly around and beneath the stone; conse quently the stone is not supported at all points and quickly works loose. The following method of setting diamonds has been found to be superior to the method just described—First drill the hole for the diamond to the usual depth, a little deeper than the greatest dimension of the stone. The drilling should be done without lubricant, as oil of any kind'tends to prevent the spelter from flowing smoothly. This being done, the hole should be closed in slightly, just enough to make it out of round. The spelter is now poured into the hole, filling it completely, and the diamond held in a pair of tweezers, is pushed into the liquid spelter in the hole until it istrikes the bottom. In doing this an 'amount of spelter equal to the displacement of the diamond is pushed out of the hole, and when this drop of spelter makes its appearance it is certain that there arc no vacant spots under the stone. After the spelter has cooled, the end of the rod in which the diamond is located can be shaped up in the customary manner. The fact that the hole is slightly out of round prevents the core of spelter from working out of the «ud of the rod.