**_“What's the name of that bur?”_**
This bur has really four names, they are: 1) “Under-Cutting” bur. 2) Hart-Shaped bur 3) “Bearing Cutter” last but not least the 4) the generic international name of “414” or “156C” (“C” meaning Carbide).
“High Speed Steel, 45-degree angle bur” is a cousin of the 156C, but not necessarily part of the family! Along with each “name” comes the reason for being used. I will explain how this one bur can literally have multiple names, depending on its use!
**This really is a very busy bur!!** I will explain its many uses & with the aid of photography. For the “Under-Cutting” the process of ‘making a seat’ for the stone is so important. There is no other bur that can accurately provide this service, why so? It helps you to carve out a little recess into the claw/prong and allows the stone to ‘sit in & against’ the metal. My angle preference of this bur is a 90-degree angle! These also come in 70-degree angles, but there isn’t any stone of that shallow angle, is there? The next bur is the great “High Speed Steel” cutting bur. As this is a very special item, I use this special cutting bur for only Engagement 4 or 6-claw head. It has a very ‘aggressive cutting’ action that the 156-Carbide cannot supply, why? As each bur is ‘hand-cut’ on a lathe, the teeth are cut deeper into the metal & are further apart. But this bur serves a dual purpose! It cuts much deeper into the claws, I know just how much metal will be removed and how the bearings will be made. As this bur is great, there is one downside, the girdle-cuts are not as ‘true’ as in the carbide. But I overcome that, by using a small round bur to make a clean ‘bearing-cut’ where the girdle of the stone meets the bearing in the claw. The HSS bur cuts both the Pavilion & Crown-Facets, together!
These burs are the ‘best friends’ of setters. Like me, I invent situations where one bur can be made interchangeable and produce quality workmanship. BTW, if a Carbide bur doesn’t cut any more, this means the teeth have worn down, throw it away and use a newer bur. “Your burs are cheap, your jewellery is expensive!” Correct size of burs makes your job so much easier.
I’d this great “156C” in every & all 1) Channel Settings. 2) Gypsy/Flush Settings. 3) Cluster rings. In closing; some burs are good and some are really fantastic, it’s for you to decide which. I am only giving you an introduction to these burs, the actual stone-setting is up to you.
BTW, in some views, I was using a “220x power Digital Microscope” and some ‘shots’ were only at 100x power. Enjoy these photographs and have fun setting your stones.