One of the most basic setting techniques is to know how to clean a large RBC (Round Brilliant Cut) Gemstone in a "4-claw/prong setting". This cleaning-process is unknown because many schools do not teach, or even know of this 'alternate method' of using a Graver to clean the claws, prior to setting.
How is this done & why a Graver & not a simple Triangular #4 cut file? These questions are going to be fully explained in this essay using photograph just showing the graver usage. I will not go into how the stone is set, but only this "special cleaning process!"
I will be using only a Flat-Sided Graver of #40, of 1.2 mm's in width..(nothing wider) I will not mention which graver manufacture is superior, only that a "Flat, #40" is required!
After you prepare the bearing-cut for the Pavilion of the stone to rest against, a definite sliver of metal will instantly appear. You must never let this 'sliver of metal' remain. The sliver is caused by the rotating HSS bur cutting into the metal & shearing off the extra piece, this is very 'normal' in the setting equation. I will now have my wide Flat graver #40 start the cutting from just above the bearing-cut and with the graver, follow down the to the bottom of the cutting. You will now simply be removing this 'ugly' looking metal. Once the Diamond is placed into the setting, this actual 'removal' is nearly 100% impossible without damaging the setting. You are following the angles of the cut, from the top of the bearing => to the bottom...(should I repeat this?) This new process just described, may be used also with a "6-claw/prong" head. No need to polish this head. What you have now achieved will be a 'brilliant & shiny surface' at it removes the sliver of metal. It cuts & polishes all the way down the claw/prong...All it takes is one "exact & a definite cut". Do not do this again, as you will get a 'faceting' edge on the side of the claw/prong. This does take some 'repetition & experience' in using the graver, to achieve this "beautiful" one cut. No file of any fine cut, or any pumice wheel can copy what your graver just achieved. Trust me! No other method can copy this with a well prepared & sharpened graver!! "Difficulty Level is about a 5 on a scale of 10!!
In my hand-drawing, you could use the file or Pumice wheel of #180 grit, but the cutting with a graver is so much better. Just one simple Bright-Cut and you're done!!!