Australian Facetors' Guild Limited

International Faceting Challenge queries

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  • 28 Feb 2019 8:45 PM
    Reply # 7191434 on 7181286

    Hi Gordon,

     

    Reading through your first post again Gordon I can better understand your queries on both the 0.01mm tolerance and the confusing E5 rule. Good  that they have been addressed and noted on this thread.

     

    This will be my first time competing in the IFC and have already started the first stone. I find it much more interesting cutting stones for comps. And has revived an old hobby I’ve had for over 40 years.

     


  • 02 Mar 2019 8:07 AM
    Reply # 7194332 on 7181286
    Anonymous member (Administrator)

    Good for you Frank, hope you succeed. I like cutting for competition as well, keeps me on the ball to hone my judging skills as well. I'm not good enough for this comp. and because I'm the co-coordinator I can't enter.

    Paul

  • 13 Mar 2019 8:53 PM
    Reply # 7216528 on 7181286

    Section E Defiant Freeform.

    This freeform cut is also one of the optional stones in the annual comp. with some minor index changes to it and a specified material.

    The drawings for both competition stones are identical, yet the index settings for the IFC stone is the reverse. The rotation of the index numbers around the crown drawing are in the opposite direction than they normally go, which would create a stone opposite hand to the drawing.

    Also some of the indexes are wrong, the crown is an emerald style cut so all indexes should follow the girdle indexes, which they don’t.

    For example step 3 girdle index is 13 so step 7, 14, and 21 should be 13. But their not they are 15.

    This error is also in the annual comp. stone.


  • 14 Mar 2019 3:02 PM
    Reply # 7218202 on 7181286
    Anonymous member (Administrator)

    Frank, it's going in the reverse because on my Gemmasta index gear  the numbers go in a clockwise direction. I test cut this stone on a GF4, it does work.  What is your index rotation? Try putting  it into Gemcad before going too much further. 

    Paul

  • 14 Mar 2019 6:41 PM
    Reply # 7218319 on 7181286
    Anonymous member (Administrator)

    When doing a freeform stone you have to remember that the stone is not symmetrical and, therefore, girdle facets cut when doing the pavilion will not necessarily line up with the crown steps. When you do a symmetrical stone, a girdle cut at 96 index is actually 48 after transfer, but because there was also one at 48 that now becomes 96, you do not recognise the difference. For a non symmetrical stone, a girdle facet cut at say 11, becomes 96-11 i.e 85. I haven't checked all the numbers on the comp stone, but I suspect that is the answer, unless someone has made a mistake.

  • 14 Mar 2019 7:53 PM
    Reply # 7218354 on 7181286
    Anonymous member (Administrator)

    That's it Bruce in a nutshell. the diagram works, I've test cut it.

    Just watch your heights as you go around, each one is different. oops! too much information there Jan!


    Paul

  • 14 Mar 2019 8:06 PM
    Reply # 7218377 on 7181286

    Hi Paul,

    I got that wrong about the index numbers being incorrect on the crown and girdle. Getting myself confused by looking at both sheets at the same time and not picking up on the differences you mentioned Bruce.

    I know the IFC stone will cut regardless of which direction the indexes go, but I had two stones disqualified in last years comp. because they spiralled in the wrong direction.

    My fault for not reading all the rules and missing the part about spirals having to rotate in the correct direction. Below is the relevant rule.

     

    SPECIAL CONDITIONS C

    “All designs must be cut according to the diagram, i.e., the facet position, basic shape, direction of any spiral effect and meet points must conform to the diagram. However, facet sizes may be altered slightly if necessary, to achieve meet points”

     

    My stones spiralled the wrong way because my index wheel was numbered in a clockwise direction, creating an anticlockwise spiral. I have since changed the numbering on the index wheel.

    It normally does not matter which way its numbered. Round, oval, square, rectangle, triangle etc will all come out the same, but freeform cuts will be opposite hand.

    I don’t want to be a nit-picker Paul, but by the rules  judges could disqualify any stone cut opposite hand to the drawing.

     


  • 15 Mar 2019 7:45 AM
    Reply # 7224159 on 7181286

    Hi Frank,

    If you click on the number surrounded by the greater and less than symbols, usually <96>, you can change the direction of the index numbers to suit the orientation of the numbers and index orientation relative to the lap on your machine.

    Regards

    Gordon 


  • 15 Mar 2019 10:48 AM
    Reply # 7224809 on 7181286

    I’m going to reverse the indexes Gordon so the stone will cut according to the drawing. I only picked up on this when I started to cut the stone on Wednesday. But happy it’s sorted and I can carry on with it, the corresponding rule for this in the IFC is E2


  • 15 Mar 2019 3:49 PM
    Reply # 7225056 on 7218377
    Anonymous member (Administrator)
    Anonymous wrote:

    Hi Paul,

    I got that wrong about the index numbers being incorrect on the crown and girdle. Getting myself confused by looking at both sheets at the same time and not picking up on the differences you mentioned Bruce.

    I know the IFC stone will cut regardless of which direction the indexes go, but I had two stones disqualified in last years comp. because they spiralled in the wrong direction.

    My fault for not reading all the rules and missing the part about spirals having to rotate in the correct direction. Below is the relevant rule.

     

    SPECIAL CONDITIONS C

    “All designs must be cut according to the diagram, i.e., the facet position, basic shape, direction of any spiral effect and meet points must conform to the diagram. However, facet sizes may be altered slightly if necessary, to achieve meet points”

     

    My stones spiralled the wrong way because my index wheel was numbered in a clockwise direction, creating an anticlockwise spiral. I have since changed the numbering on the index wheel.

    It normally does not matter which way its numbered. Round, oval, square, rectangle, triangle etc will all come out the same, but freeform cuts will be opposite hand.

    I don’t want to be a nit-picker Paul, but by the rules  judges could disqualify any stone cut opposite hand to the drawing.

     


    Yes that's correct. If the facets are spiralling in the opposite direction to the competition schedule diagram, the stone doesn't match the diagram and is therefore ineligible. Something to watch out for. There are few designs in  current comps like that, 2019 Gemboree, the 2020 IFC and last years 2018 AFG Comp. which was not a deliberate trap. don't be complacent and just follow the diagram, check it out first and make sure you know how to cut it before cutting. All good. Paul
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