Preciosa

The Masters of Crystal

Hand Setting

Instruction (6)
The same care that Preciosa devotes to the production and packing of the stones is necessary in stones setting. Incorrect handling may damage the stones, especially their points and edges. The stones would then lose their ideal optical as well as aesthetic properties (brilliance and fire) and would not shine in jewellery. To preserve all the optical properties and aesthetic features of the stones by Preciosa when making jewellery, it is necessary to observe the correct setting techniques.

Useful Advices for Hand Setting

Step 1. Drill the holes for the stones’ seats

First use a small ball bur to predrill small pilot holes. 


Then, using a twist drill, begin drilling larger holes in the centre of the pilot holes. Select a drill of such a diameter so that the resulting holes may not restrict the  possibility of adjusting the spacing between the holes, or weaken the metal of the jewel. Conversely, a drill of a small diameter might easily break.
 

 Step 2. Redrill the holes conically

  • Redrill the holes conically using a bud bur. The holes are redrilled conically to retain the strength of the metal of the jewel while removing the excess metal. This will later enable you to reduce the pressure you must exert on the setting bur while drilling the stones’ seats. Stop drilling just before reaching the diameter of the stones in order not to enlarge the holes too much.

 Step 3. Drill the seats of the stones

Drill the seats using a series of high speed (H.S.) setting burs graded in size. For each seat begin with a bur that is smaller than the diameter of the stone to be set. Then it will only be sufficient to slightly enlarge the seat for the stone to go in it tightly. At this stage, it is recommended to work as precisely as possible as it is not necessary to remove a large quantity of metal.

As emphasised above, the stones should fit in the seats adequately tightly. If the seat is too tight, do not use the next size of the H.S. setting bur as it may be too large. If the exact size bur is not available, try a different sort of bur made of tool steel, the “hart” type of bur, for instance, which will shave off just the exact amount of metal for the stone to fit in the seat sufficiently tightly. There is still one more way how to enlarge the seat: use a smaller H.S setting bur and swirl it around the inside of the seat, thus enlarging it evenly. While doing this, check continually whether the seat is already large enough for the stone to fit in it tightly, thus avoiding undue enlargement . 

Step 4. Set the stone

The metal of the jewel the stone will be set in should be more than 1mm thick so that the stones would not fall out of their seats. First, brush the metal, remove the filings and clean each stone before setting it. To handle the stones use beeswax with admixed charcoal crushed to a fine powder, spread it conically on the point of the tool and touch only the table facets with it. It is important that both the seats and stones should be absolutely clean.
 

Having placed each stone over its corresponding seat, press it down imbedding it in the seat properly. The stone should be pressed down only with slight force perpendicular to the plane of the metal so that the stone would not get stuck askew in its seat. This can be done with any “soft” tool tapering into a small flat surface. Brass or copper will serve as an ideal material for this, too.

Finally, all the stones should be set with their tables level with the metal of the jewel.

Warning!  To imbed or adjust the stones, do not use a hammer. The stones might break or otherwise get damaged.

Step 5. Secure the stones

After the stones have been imbedded in their seats, it is necessary to secure them in correct positions. Otherwise they may break or get damaged.
Incorrect procedure

Correct procedure
To secure the stones, you can use one of the following techniques, or a combination of these:
a)  Pressure
If a small stone is imbedded in the seat tightly, it can usually be secured with very little effort. This can be done, for instance, with a small round graver, or a flat tip prong pusher. Hold the tool slightly pressed against the rim of the metal and draw it repeatedly around the stone in one direction while pushing it down. Tilting the tool gently just to use its edge, you can concentrate the pressure to compress the metal and move it around the stone much easier.

b) Tapping
If the stone is imbedded in the seat loosely, you can use a metal tapping technique to move the metal around the stone. This is done with a lightweight chaser’s hammer and a tapping tool tapering into a flat circular tip.

9.4.2008 0:04:12 | read 12682x

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