Why is a "156C" bur so very important? => 17 photos. ESSAY #1, of 2 posts

 Of all the intricate burs on the diamond setters bench, this one bur can do so much for your stone setting. Remember, don't get confused with the "HSS" bur, also known as "High Speed Steel".

 => The teeth of the Carbide Burs are so much closer than the HSS burs, as shown further below!

 The particular letter signifies that this bur 'C' is an acronym of Carbide Steel! This bur is also named 'bearing cutter', plus they come in 45, 70 & 90angles.

 Please be specific of your needs upon ordering from your suppliers, as mistakes could be costly for you.

 These '156' burs are made in many sizes from #005 all the way up to #070.

 What are their many uses? =>Channel Setting, Cluster Settings and preliminary Pave' Settings & 4-Claw Engagement Rings.

Please examine the 'closely knit group of teeth' on the Carbide bur.

 This thin (45degree angle) cutting edge bur is best for cutting 'claw bearings' only.
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 Here is a great example of the 90degree angle bur beside the two 45degree angle burs.

  This bur purposely cut a bearing on one side of the channel wall ONLY. This is used to cut a groove for the Girdle that will be created. I'll rotate the ring and prepare for 'another seat' on the opposite side.

 On a 'cluster style ring', the bottom of the bur will be prepared for the Pavillion of the stone. WHY?

 It is best to 'open' up the setting hole further with a round bur.  This will give the setter ample room to cut seats where necessary.

When using your rotating bur, keep the bur in a vertical position.

 When preparing to set any row of stones (as shown) it is required to drill THROUGH the metal and give more access to the Culets. 

 There is little, or no room for the polishing (used material) to escape.

The mini-stones were held together with greatest assistance of those 156C burs. 

 =>The selected bur size must never be the same as the stone. The "rule of choosing a bur", is it must be 3/4's of the stone.

  In this tray of burs I'm leaving the largest burs in a group all by themselves. The smallest 156C burs will be kept seperately. If I need even a smaller size of burs, I'll keep them in another tray.

 Enclosed in this bur tray are Genuine Rubies, my formidable task is to pick ONE bur out of many, that is 3/4's of the size of the stone. IS THIS AN EASY TASK?

 The depth of the teeth and how they are created are so extremely important in creating seats in metal, for stone setting.

 => PLEASE GO TO THE NEXT ESSAY (version #2) for additional setting notes.

Why are "156" burs so very important => 10 photos. Essay #2, of 2 POSTS.

  The main problem is that the Carbide steel is quite soft as compared with the HSS burs. What happens is that the bur makes contact with a hard metal, the claws get easily damaged & ruined.

This 45degree angle cutting bur is great for cutting bearings.

How far down into the bezel should the HSS bur go? The 'Rule' is that the bur should not go deeper than the tip of the teeth.

In this photo you can now see two shapes of the burs...45 & the 90 degree angles.

 This is a photo of slightly worn teeth on a 156C bur.

                              (These are the teeth on a HSS BUR)

  (These are my favourite photos, that I personally took.)

 You can see each individual tooth of the bur starting to cut a bearing. WOW, eh!

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 You can now see just how low the rotating bur should go. 'The tip of the teeth' IS THE RULE FOR DECIDING THE DEPTH INTO THE BEZEL WALL. 

  The rotating bur mustn't go any lower than shown here!!!

 

  (My diagram drawings are not perfect, but 'the thoughts' are there.)

 You can easily see where the HSS bur teeth are about to cut into the pre-notched claw.