What burs to use in setting a round, "Brilliant-Cut" shaped gemstone => 18 photos

 We all know how to set diamonds, agree? But the exact rules differ for setting a large round stone in an engagement ring. Not to mention what kind of burs to use? This is where your experience & training start.

-------------------------------------------------------

 These two burs are the epitome of setting tools that will prepare the claws for gemstone setting. These burs are shaped exactly like the stone with the same angles as a diamond.

 When I need a bur to fit the gemstone, they are all placed in my wooden box. They are all in sequential order, from small to large. I have no need to search and waste my time, where that bur is.

 CUTTING A 'SEAT' FOR THE GEM-STONE: 

 The only bur that is to be chosen is the HSS bur, why? This bur has the very same shape as the stone. 

 In my diagram, I suggested a "156C", but when we are dealing with larger stones, I'd stay with the High Speed Steel bur as the dimensions are the same as the stone.

This diagram was created to show the placement of the bur in relationship to the claw. Please notice how the bur is angled.

 In this essay, we are dealing with a basic 4-claw setting. Please notice that the 4 claws are at equal distance from each other.

 This '156c' cutting bur has a 90degree angle shape, but not to be confused with the HSS bur with the same angles. The only difference is the spacing and depth of the bur teeth.

   I sometimes suggest, for a small stone setting, to round the tops  BEFORE the actual stone setting. This is not required with a larger stone setting.

 The rounding of the claws is not done with a file, but only with a "77B", Cup Bur. Using these burs, the tips will be of equal shape.

 Here is a side-view of the 156C setting bur. You will notice that the close proximity of the teeth and the depth of the claws are quite shallow. This in itself is not good for the aggressive cutting that is required.

  Here is an assortment of "77B" Cup Burs. The selected bur must be 30-50% larger than the claw; this will allow the bur teeth to cut and shape the claw tips.

 Here is another close-up view of the "156C" bur. This bur actually has 5 names to it, and they are all equally acceptable.

 When the edges of the teeth of the 156C bur get worn, they can't cut, and they can't be repaired, as seen in this photo.

 With the larger HSS burs, there is an excellent chance of repairing the worn teeth. This technique has been discussed in depth in recent essays.

  The two front burs in this photo need to be recut. This is a common occurrence with the bur cutting into the white metal in the gold. ALWAYS BE AWARE OF THIS ONGOING PROBLEM. There is no need to be alarmed; it happens all the time.

  As the 156C burs are reasonably priced, I always have duplicate or triplicate burs for each size. As a Diamond Setter, I always had a vast inventory to have at my disposal.

 For very small stones, as seen here, I didn't use the very aggressive HSS burs. The reason is that those burs would cut deep and ruin the delicate claws.

 When you are getting ready to start drilling the claws. I suggest that you should 'spread out' the claws. This will enable you to get the bur into the inside of the claw setting basket.

 As I mentioned just before, the HSS bur is too aggressive for small

stones as seen here.

 

 

 All new burs need to be well cared for; this is why I keep them in the plastic container AND WELL OILED in case rust starts.

 

  You have an option as to which bur to use. I suggest a bur that has the same angles as that of a gemstone.

 I don't entertain using a 'bearing-cutter'as the angles are too shallow for a stone setting application. The angles of the gemstones should be the same as the bur.

  The simple process of setting a gemstone is not that easy. Why is this? There are many things that might go wrong; my position here as a Diamond Setter is to enlighten you and succeed.

 That is just why it took me 9 YEARS to learn my craft. Have fun!