- Aug 4, 2008
No it didn't occur to me the girdle might have been reworked, but IIRC Al Gilbertson's book did say that most old cuts had extremely thin or even no girdle at all. So if it got chipped over the years it makes sense it could have been reworked to remove the chips.
Karl, I've been thinking about the best way to do this without consuming too much of your time, but putting Area B to bed for sure one way or another.Ok im starting to think that using someones diamond is a mistake.
I'm not getting it to be super close(can't duplicate variations in the real diamond without a full scan on a high end scanner at the best settings) and I'm starting to see why they fell to the wayside. I am not comfortable talking about that when discussing someones diamond.
@prs give me some starting numbers in the B zone.
What was surprising is that you get less than a 1 degree or just slightly over depending on who you ask swing in pavilion angles for a modern RB.This is so interesting! Diamonds = higher maths!
Wow, thank you Karl, I was half expecting Area B to be a complete dud. When you said the AGS cut guide didn't properly account for obstruction that's when I went looking for more info, and found Bruce's article.Here is why 37 just because your a lil crazy that way :}
I tried 35 and there was min performance change.
I have this fantastic image in my OEC file, but I've no idea where it came from. Maybe one of @Karl_K's articles?I'm now feeling as lost as I did in the one college math class I was required to take, so will just look forward to the gorgeous photos when you find this diamond...
Actually it's basic trigonometry that I learned in grammar school when I was about 12 years old. I think it stuck in my memory because that was long before calculators and computers existed. We had to draw it out on paper and use a book of log and trig tables, together with a slide rule to do the calculations.This is so interesting! Diamonds = higher maths!
If that area is too twitchy perhaps we should just move on. Maybe try a CA of 35.0°? This would be interesting in that the crown would be close to ideal, but the PAs would be in another universe.Ok I played with those new numbers a little, they are extremely twitchy about the upper girdle angle with the upper girdle are showing week light return to mostly leakage. I think there might be some good combos there but they are not going to be cuttable within reason.
Do you want me to play with them some more or move on to a different area?
I am willing to do either.
@Karl_K I'm just shooting in the dark trying to pick combinations that might work, I may have gotten lucky once, but if this is anything like me playing roulette in Vegas I can assure you we are headed for a long losing streak!