Master Class Single Stone

[Ronald A Maitland]

Looking at the diagram for the master class single stone competition, several index settings are in decimal numbers. I have never seen this before. Does one round up/down, or use the cheater?

Ron Maitland

[master1975]

The pavilion and crown angles are listed to the hundredth of a degree. The index settings are whole numbers.

[Dennis Anderson in sunny Southern California]

It is normal for the designs in the SSC to have angles listed in decimal to two decimal places. This is a result of the computer designs having this capability. You are expected to interpolate on your faceting machine to best approach this angle and cut all the facets in a tier to that consistent angle. If you do this well, the result will be a stone that will be judged based on the parameters in the judging manual. There is no means for the judge to measure angles to 1/100ths of a degree.

[Ronald A Maitland]

The crown tier C facets show indexes in decimal tenths.

Ron

[Ronald A Maitland]

For anyone cutting this stone, I figure the correct C indexes to be; 5-19-29-43-53-67-77-92.

Ron

[Ronald A Maitland]

Sorry. Last index should be 91.

Ron

[Alan Balmer]

Hi, Ron. There seems to be a discrepancy between the design in the newsletter and the one on the website. I think the website version is correct (no fractional indexes). Click on “Competition” in the menu. No login required.

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