Minimize or Eliminate Breakage of Stones in V-Shaped Prongs

Setting a pear or marquise in a V-shaped prong without breaking the stone can be difficult. Moreover, the points of such stones are susceptible to damage during the course of normal wear. Certified Master Bench Jeweler Stephen Hermanson of Galloway and Moseley, Sumter, S.C., says the key to preventing damage is to avoid contact between the point of the stone and the V-shaped prong. He suggests this trick:

1. Use a small ball burr or heart burr (depending on the stone’s proportions) to create a channel or seat for the point of the stone. The channel or seat should hug the stone.

2. After creating the proper fit for the point of the stone, use a small bud burr, ball burr, or drill bit to open the area at the junction of the V-shaped prong and the stone. (The blue portion of both diagrams in the illustration indicates the opened area.) After setting, the point prong should be in contact with the stone, but it shouldn’t be touching any portion of the stone’s extreme point. (The resulting gap cannot be seen after the stone is set.)

Benefits for the Working Bench Jeweler

Cost savings. Minimizing or eliminating breakage during setting reduces the number of stones a bench jeweler has to replace.
Customer satisfaction. The technique reduces the risk that a stone will break during normal wear, an added benefit for the customer.
Continuing education. This technique will be helpful to anyone taking the practical bench tests of the JA Bench Jeweler Certification program.

JCK, August 2000
Mark B. Mann | 800-759-9997 | (fax) 800-616-9997