“What's the name of that bur?”
This very useful bur has four names, they are:
1) “Under-Cutting”
bur!
2) “High-Speed Steel”
45-degree angle bur!
3) “Bearing Cutter”!
4) The common & generic name is “414” or “156C” (“C” means Carbide).
(I, as a Diamond Setter, have an estimated 175 "High-Speed Steel" burs in my inventory!)
(I, as a Diamond Setter, have an estimated 175 "High-Speed Steel" burs in my inventory!)
Along with each “name” comes the reason for
being used. I will demonstrate how this one bur can literally have multiple
names, depending on its immediate use! This can be a really very busy bur!!
I will now explain its many uses and with the
aid of photography. For example the “Under-Cutting”
the process of 'making a seat' for the stone is so very
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.
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 preference for this bur is at "90-degree" angle! These also come in "70-degree" angles, but there isn't any stone
of that shallow angle, is there?
(Some setters will use the "70degree" angle to cut only a bearing!)
(Some setters will use the "70degree" angle to cut only a bearing!)
The next bur is the great “High-Speed Steel” cutting bur. As this is a very
special setting tool, I use this’ special cutting bur’ for only Engagement
4-6 claw configuration. It has a very 'aggressive cutting' action that the 156-Carbide
cannot supply, why?
Each bur is hand-cut on a lathe, the teeth are
deeper into the metal & the teeth are further apart.
But this bur has 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.
But this bur has 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.
This little bur is really small, it measures only 0.85mm's. Even this small, you can still see the uneven machining of the teeth at the edges.
As this bur is ‘hand-made on a lathe’ there is one 'negative'! The girdle 'cuts' are not as uniform or 'evenly made' as with the 156C-Carbide bur.
But I can easily overcome this easy problem, by using a small bud-shaped bur to make a clean 'bearing-cut' where the girdle of the stone will be located.
But I can easily overcome this easy problem, by using a small bud-shaped bur to make a clean 'bearing-cut' where the girdle of the stone will be located.
Here is a better photo of the bud-bur cuts!
The HSS bur can cut both the "Pavilion & Crown-Facets", together!
The third use of this bur is to cut 'bearings'
or grooves into small claws. Its name is quite obvious, it's purpose is to cut
'seats' for the girdle, for very small stones.
In a ring of a cluster-top pattern, I wouldn't use any HSS bur, but I would use only a 156C "Carbide" bur in its place.
In a ring of a cluster-top pattern, I wouldn't use any HSS bur, but I would use only a 156C "Carbide" bur in its place.
I will use only a 156C bur on theses delicate settings.
I attempt to keep my larger & smaller burs separate, this makes this so easy to locate the correct bur, at a moments notice!
As both are made of Carbon Steel, but the HSS has been treated differently and is very long-lasting in the 'family of burs', but working in different situations.
In this essay, the generic
named bur “156C”, or “414”
as shown in its 6-bur package.
These burs are the "best friends" of setters, I always invent situations where one bur can be interchangeable and still produce quality workmanship.
These burs are the "best friends" of setters, I always invent situations where one bur can be interchangeable and still produce quality workmanship.
I'd use a "156C" bur in the following delicate procedures.
1)Channel Setting:
2) Gypsy/Flush Setting: again only a 156C bur is required!
Never use any "aggressive" cutting bur in this application. You need all of the metal to carefully push the metal over the stone. The High-Speed Steel bur removes mostly all of that much-needed metal.
3)Mini-cluster rings: Here is another setting pattern that must not use any rough cutting bur.
Every bit of metal is needed, as some stones could be only 1-2 millimetres in diameter.
I wouldn't use the aggressive
“High-Speed Steel” in any of these above instances.
BTW, many of these burs being shown are acceptable in 'most cases'. I will shy away from any rough-cutting bur even if it's setting a small stone.
(This is only my personal preference!)
BTW, many of these burs being shown are acceptable in 'most cases'. I will shy away from any rough-cutting bur even if it's setting a small stone.
(This is only my personal preference!)
Therefore in closing: Some burs are good &
some are just really ’fantastic’, it's for you to decide which, when & where to use them.
In this essay, I am only giving you a 'bur-guide'. The actual stone-setting techniques can be found in other essays.
Enjoy these photographs and have fun setting your stones!
In this essay, I am only giving you a 'bur-guide'. The actual stone-setting techniques can be found in other essays.
Enjoy these photographs and have fun setting your stones!
