One of the primary functions of bench jewelers is setting stones. We understand this and want to share some techniques that we use that should benefit you. We will be describing the process required to set a stone in a series 283 V prong Marquis setting. For this job you will need the following tools.
Trial fit your stone by placing it into the head. Adjust spacing and location of the prongs carefully. Using a pair of chain nose pliers make sure the jaws are prepped and smooth to avoid leaving tool marks. It is important to position the pliers up and down so you can grab the whole length of the prong not just the prong tip and move the whole prong as needed. When finished the stone should fit just above its final resting place. Use a bearing or 90 degree bur to cut the seat in each V prong. The bur should just fit within the V of the prong without extending over the sides. This will keep the bur from jumping out of the V and wrapping around the outside leaving tool marks. The faster you spin the bur the more control you have. Use light pressure to cut the seats. Most fancy shaped stones have points on them so you will have to drill a shallow hole in the center of the seat on the V prongs with a round bur to provide clearance for the point. For sharper thinner points it may be necessary to drill a smaller clearance hole inside the first hole. While still using a round bur cut a small groove down the center of the V prong from the seat. This will allow room for the corner facet of the stone's pavilion and help prevent chipping. Cut seats forty to fifty percent deep in the side prongs with a 90 degree bur. Select a bur that will cut one prong at a time but is not too small to fit between the prongs and possibly wrap leaving tool marks. After the seats are cut use your knife edge graver to remove any burs that are left on the sides of the seats. Test fit your stone inside the seats to make any corrections that are needed. Place the stone into the seats and with a pair of chain nose pliers and pinch the end of the V prong to tighten it over the stone. Do this for both V prongs making sure the stone is straight. A good way to do this is to tighten a little on one V wrong and then the other going back and forth until the V prongs are in their final position. Using chain nose pliers bring the side prongs into final position. Check to assure the stone is straight and tight. Shape and finish the V prongs with a sanding disc and a square edge blue silicone wheel. If you need to define the inside of the V at this time do so with a polished flat graver. Next shape and finish the side prongs with a sanding disk, cup bur, and a sharp blue silicone wheel. Make sure to use a cup bur that is not too small when shaping your prongs and use bur lube. Follow up with the number 38 graver to remove any flashing that may have occurred. Finely polish the setting with traditional polishing methods. With these easy steps you now have a great set stone that will compliment any ring and wow any customer. Congratulations on a job well done and visit benchjeweler.com for more great videos, tips, and products.