I have just read an article by Jeff Graham sent to me by email (IGS) re cutting the pavilion first on a gemstone.
If you have not read this article, I would advise anyone who facets to read it.
He is absolutely right about cutting the pavilion first - I have been doing this for many years.
Not only does one have to make sure your pavilion angles are correct for the stone you are cutting, but you also must have enough material for the crown. This is where cutting the pavilion first is good.
Most people find it hard to determine the correct depth of the pavilion if they cut the crown first and by cutting the pavilion first you know how much material is left for the crown, if you find it too short then recut the pavilion a little smaller in diameter until you have enough - It is very difficult to do this if cutting the crown first.
Even if you do not have quite enough material to form the Table of the stone, you can decrease the angles of the girdle break facets to lower the crown table, this however will increase your table width, but will not effect the brilliance of the stone. Quite often I will increase the crown table from the norm (50-60%) to around 80% by lowering the girdle break facets to give me more light to enter through to the pavilion, especially for darker stones.
Regards Trevor
LoL never did it any other way, No i am not any smarter just have not been faceting as long as you, I looked in to faceting many years ago and could not get my head around how it was done with out a lot of guessing . Then I found meet point faceting and cutting the Pavillion first. Ya there is still some ( eye ball ) work to get the best yield , Thank you for the idea of a bigger table on dark material I was sneaking up on it as I did not like the idea of cutting a shallow ( fish eye ) stone just for color thank you again.
HI 707 chrisa
Glad you got to do faceting as it is one of the best relaxing hobbies one can get and to turn a piece of rock into a gem is still breathtaking to me as I am sure it is to you.
I have put my faceting down under onto U tube. It is faceting the standard brilliant using some of the older techniques. It might be helpful to you or just boring (heehee) as it was made foe begginers.
Regards Trev
I like the way you used a 4inch lap to rough to round, keeps the swarf in, cheaper and is easier to store . A 4inch sintered lap will last for ever . I always like to visit people in their studios ,your video made me feel like that , I will view it again for more hidden gems . Thank you
Your Welcome. 