Aussie Lapidary Forum
LAPIDARY => Gemstone Faceting => Topic started by: FlashGP on September 29, 2014, 12:33:25 AM
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I am not sure if anyone has done this since Pegatha's 25 July 2014 post, but here is a 64 index version I re-engineered using Gem Cad. There is an error in the design posted by Moonshaddow_dancer, two of the tiers are transposed.
I started re-engineering the design yesterday on the 27th as an exercise and have just finished it.
The length of the edges around the curve are the secret to the design, they need to progressively increase at an ever increasing rate, the girdle also needs to stay flat, otherwise it progressively thins and ultimately starts cutting the pavilion facets.
I have also uploaded a version optimised for quartz. It has a much higher Crown than the original design.
http://aussielapidaryforum.com/forum/index.php?action=media;sa=item;in=6999 (http://aussielapidaryforum.com/forum/index.php?action=media;sa=item;in=6999) for the 64 index Yin Yang optimised for Quartz
http://aussielapidaryforum.com/forum/index.php?action=media;sa=item;in=6998 (http://aussielapidaryforum.com/forum/index.php?action=media;sa=item;in=6998) for the 64 index Yin Yang using angles approximating the 96 index design posted by Moonshaddow_dancer.
enjoy.
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Your a brave man FlashGP trying to squeeze 12 facets into a 32 index rotation :D. The only way I can see of getting that even girdle is to either increase the number of girdle facets on each half from 12 to 16, or reduce it to 8, then modify the crown and pavilion facets accordingly. Just a thought ;)
GR
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I did it using 12 fold radial symetry then cutting a second row meeting at the centre. The index settings are not evenly spaced. Some increase by 2 some 3 some 4
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Continued, (now I've finished being the family taxi). It works in a similar manner to fitting a 10 or 9 fold design into a 96 index pattern. Once you set the symmetry and start index for the series, Gemcad spaces the facets evenly so the spacing changes are evenly spaced around the stone.
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Hi FlashGP.
Your diagram says that there is an uneven girdle and that two meets do not meet. I make it a lot more than two not meeting.
Pav.:- 1, 3, 6, 8, 12, 14, etc.
Crown:- 2, 4, 8, 10, 13, etc.
Why not have the crown matching the pav., and instead of fudging the "F" facets, fudge the smaller "L" facets?
No need for the "M" facets on the crown.
Just an idea that probably wouldn't work as I don't have Gemcad.
Regards, Ghost
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Why not have the crown matching the pav., and instead of fudging the "F" facets, fudge the smaller "L" facets
I tried just fudging thesmaller facets, but the girdle slowly spiralled to oblivion and the crown facets cut into the pavillion.
When cutting I set two meetpoints as the points to cut to. The first being the distance on the curve of the design, the other being the girdle meet point. This caused Gemcad to calculate the angle needed for a given index. Since the girdle is reasonably level, the other girdle meetpoint should be pretty close, or looks that way in the diagrams.
I have noticed that if you use turn the index adjuster +3 on the pavillion, you need to go 6 graduations in the other direction when you transfer and cut the crown. E.g. +3 - -6 = -3 or 3 stops past 0 in the other direction.
I reasoned the same thing is happening with the crown facets, because they are not evenly spaced on the index wheel. My first attempts used the same index numbers for the crown as the girdle and the girdle tapered as I cut. The facet I mentioned as being out was set as a result of setting 3 meetpoints so Gemcad returned both angle and index as I could not get a level girdle fudging it in either direction.
It was about .4 of an index out, so I selected the closest index then recalculated the angle for the chosen index using one girdle meet point and the edge spacing on the curve for that facet.
I supose the only way to confirm is to cut it on a 64 index wheel in something cheap like quarts or TV glass and see if it works.
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I am not sure if anyone has done this since Pegatha's 25 July 2014 post, but here is a 64 index version I re-engineered using Gem Cad. There is an error in the design posted by Moonshaddow_dancer, two of the tiers are transposed.
I started re-engineering the design yesterday on the 27th as an exercise and have just finished it.
The length of the edges around the curve are the secret to the design, they need to progressively increase at an ever increasing rate, the girdle also needs to stay flat, otherwise it progressively thins and ultimately starts cutting the pavilion facets.
I have also uploaded a version optimised for quartz. It has a much higher Crown than the original design.
http://aussielapidaryforum.com/forum/index.php?action=media;sa=item;in=6999 (http://aussielapidaryforum.com/forum/index.php?action=media;sa=item;in=6999) for the 64 index Yin Yang optimised for Quartz
http://aussielapidaryforum.com/forum/index.php?action=media;sa=item;in=6998 (http://aussielapidaryforum.com/forum/index.php?action=media;sa=item;in=6998) for the 64 index Yin Yang using angles approximating the 96 index design posted by Moonshaddow_dancer.
enjoy.
Hi FlashGP, is there any chance you have the design pattern to share for the 64 index wheel. I need another challenge and I only have a 64 and a 60 index. This looks like a fantastic design. Regards Cliff
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Changed it to 64 for you. From facetdiagrams.org
(http://aussielapidaryforum.com/forum/gallery/8/5704-081117074843.jpeg)
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Alternatively cut 32 pavilion facets instead of the indicated 16.
Regards, Ghost.
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Thanks Makky Brown and to FlashtGP for the design. Have you guys cut this design on 64 wheel? I think I'll stick to a 16 index pavilion. Ghost must be pulling my leg with a 32 index cut. But wouldn't that be something....Regards Cliff
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Some design on the Gemmology Project Website include 24 and 32 single angle pavilions, and have very nice effects. Very easy to do as only one angle and no meets except one at the culet The advantage with yin-yang is that the pavilion will match the crown at the girdle.
An SRB has 16 Break facets on the girdle and another 8 Mains that reach the girdle, thats 24.
The US Facetor's Guild has a design for a 12 main SRB, which has 24 Break facets on girdle and 12 mains reaching the girdle making 36.
Don't be afraid to experiment.
Regards, Ghost.
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Thanks Makky Brown and to FlashtGP for the design. Have you guys cut this design on 64 wheel? I think I'll stick to a 16 index pavilion. Ghost must be pulling my leg with a 32 index cut. But wouldn't that be something....Regards Cliff
Sadly, no. I only have a 96 and 120 index wheels. I may have to get a 64 index as the Gemboree Novice comp has a few 64 index designs and one of them has fractional indexes when converted to a 96 infexx design.
Regards
Flash
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The Ventilatore design by Marco Voltolini on the Gemology Project has four vanes instead of the two in the Yin Yang design. It also has the single angle 32 facet pavilion I mentioned above. Ventilatore instructions are for a 96 index but will convert to a 64 perfectly.
Just divide each index number by 3 and multiply by 2.
http://www.gemologyproject.com/wiki/index.php?title=Voltolini_-_Ventilatore
Regards, Ghost.