Using "156C" and "HSS" burs - 12 photos

 Burs are our 'tools of the trade', what would we do without them? We work with them and they work with 'us'. In this essay, we will honour them midst all of their complex designs

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 These amazing "HSS" High Speed Steel burs are ALL cut...one at a time, by hand! That is by an operator at his designing & cutting wheel.

  I used my "156C" bur or 'Under-Cutting' bur on the Gypsy setting ring. The letter "C" means that it is made of (softer) Carbide steel. These teeth are made much closer together than the HSS cutting bur.

I used ONLY  the thinner setting-bur 156C to create a thinner bearing for the thinner Girdle. This is just for creating a delicate resting place for the girdle of the stone.

The HSS bur will cut a very wide bearing and eventually not giving me any luxury of quality setting.

 In this photo, I used two bur styles & shapes, why? This ring warranted two different styles of burs. I never relied upon one style of bur, together my gem-setting results was made easier for me.

When these burs have worn down, it's too expensive to repair any of these burs. Just discard them and buy a newer bur. The HSS bur can be repaired by recutting the teeth.

 In preparing to set these stones, I use a "156C" bur. These teeth have to ability to create only a bearing needed to set any stone as being shown here. For this 'ring project', we are only concerned in making a little groove for the Girdle of the stone.

 The HSS bur will give you a wider cutting bearing, I'd stay away from these burs. We need only a thin & delicate groove for this stone.

 Many times I found in my past projects, I had to modify and alter the bearing to allow for a thicker girdle. I used a slightly larger round bur to make these subtle modifications and adjustments. 

 These 156C burs are relatively cheap to buy from your tool supplier.

 These 'specially cut' HSS burs are a different matter, for a box of these burs as shown in this photo could reach well into $150.00 or more. 

 Compare the cutting teeth array on either of these two styles of burs. They might look the same, but their uses are are so different.

 Here is just one HSS bur, examine the number of teeth. Then on the above photo closely compare the "156C" tooth structure. The purposes are all so vastly different.

 As an active Diamond Setter, I have amassed literally many hundreds of burs.

 

 

 You just have no idea when particular bur is required. Thus having almost 750 burs is quite normal in this highly specialized craft.

 There are two shapes of these 156C burs, each one is still very in stone setting.

 The thinner bur in the center of this photo is quite good for preparing a seat for the stone. While the bur on the near left is used primarily for the Pavilion of the stone.

 The larger bur is cut at 90degree angle, while the thinner bur is cut at 70degree angle.

 When you need a sharp edged bur, buy a packet of 6, instead one at a time. When the teeth get worn, "Good-Bye" and discard it. 

 You can see where the soft Carbide steel is on a short life-span and the edges of the teeth are now showing signs of wear.

 

 I'm hoping that this 'introduction to burs' has been a good help to you. (Gerry Lewy)
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