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  1. #1
    Join Date
    Sep 2005
    Posts
    91

    Facet Machine

    I am seriously thinking about trying to automate my facet machine. It doesn’t have to completely facet a stone from start to finish. I would like automating it as much as possible. Has any thought about the possibility of CNC retrofitting a facet machine. Any thoughts. It would really be nice if I could do something with GemCad and convert it to G code. Sounds insane but I bet it would be a fun project not to mention very profitable. People buy cut gemstones like crazy.

  2. #2
    Join Date
    May 2005
    Posts
    1810
    We are definately going to need pics for this thread.....

    I have no idea what a facet machine looks like and I have been around machines most of my life. I have a feeling I am not alone - I might be wrong.

    We definately need to see this machine with a brief (or detailed) description of the operation and process.

    Scott
    Consistency is a good thing....unless you're consistently an idiot.

  3. #3
    Join Date
    Sep 2005
    Posts
    91

    Crash Course

    I have a Mark IV found at this link.
    http://www.gravescompany.com/facetin...ting%20Machine

    A crash course in gem cutting can be found here
    http://www.rockhounds.com/rockshop/g...ns/index.shtml

    I have a small machine shop (lathe, mill, etc.) so I can make my own equipment and mods.

    Any thoughts?

  4. #4
    Join Date
    May 2005
    Posts
    1810
    Neat! Thanks for the education.

    It seems very possible to automate the equipment, sure. But since I have never faceted a stone I have no idea what portion is art and what portion is automatable.

    Automating the positioners would not be terribly difficult - it would be a task, but because the thing is relatively small it would likely be easier and less expensive than building a cutting machine that has to move a 500 pound gantry. I think you would want to use very accurate components and designs with zero backlash and high tolerances since any backlash or inaccuracies would likely be highly visibile at the intersections of the facets, etc.

    Looks like a very cool trade/hobby to know.
    Consistency is a good thing....unless you're consistently an idiot.

  5. #5
    Join Date
    Jul 2004
    Posts
    242
    Jarvis Tool actually made a CNC Facetron faceting machine

    http://www.facetron.com/index.html

    They used to have a few pics on the website but nothing anymore, I'm sure some googling would turn it up.

    Also for you DIY'ers, there are some plans to build your own faceting machine which would be a good project:

    http://www.gearloose.com/newgem.html

  6. #6
    Join Date
    Aug 2004
    Posts
    2849
    I suspect that the reason CNC is not used in the facetting of gemstones has alot to do with the use of dops and how the gemstone is attached to the dop....I think that slight bit of inaccuracy in attaching the gemstone to the dop to facet the table and then transfering the gemstone to facet the underside is the primary reason CNC is not used in facet machines.

  7. #7
    Join Date
    Jul 2004
    Posts
    242
    Quote Originally Posted by ViperTX
    I suspect that the reason CNC is not used in the facetting of gemstones has alot to do with the use of dops and how the gemstone is attached to the dop....I think that slight bit of inaccuracy in attaching the gemstone to the dop to facet the table and then transfering the gemstone to facet the underside is the primary reason CNC is not used in facet machines.
    No, that's not a valid reason. When you attach the rough to the dop, you just get it close for cutting the pavilion. Upon transfering to cut the crown & table you can pick up some inaccuracy in the transfer if you aren't careful.

    CNC would be ideal for faceting & prepolish but for the final polish, it will have to be done by hand in most cases. A number of facetable materials have different crystal planes and it's common for some facets to polish easier than others and that's where you have to have human interaction.

    Faceting gets pretty mundane & monotinous especially getting to the pre-polish stage. CNC would be nice for that.

  8. #8
    Join Date
    Jul 2005
    Posts
    12177
    Rustyoldo has it right; it is monotonous and the final details do need human intervention. I think the biggest users of automated facetting processes are the Ekati and Diavik diamond mines in Canada's Northwest Territories.

  9. #9
    Join Date
    Sep 2005
    Posts
    91

    My Thoughts

    I new it would be seriously difficult to automate the process from start to finish. My thoughts was to automate the preform steps and also if I could automate the facet cutting and ultra-laping. Then do the transfer and do the same on the opposite side. Mainly automate the indexing for the facets(single axis).

  10. #10
    Join Date
    Apr 2003
    Posts
    42

    Into the DARK CLOSET OF PARTS 'N PROJECTS UNDONE

    Well, it got me started thinking about faceting again....but making very small gems hasn't been introduced into my blood yet....how about much larger ? We did make a sphere machine and we also worked out a method of going through the various stages of grit without grit, (up to 10,000 or so, and in about 1/4 the time...from 1" stone spheres to basket ball size.....)

    And the reason we did not go larger is because we put it on the same table as a home brewed lap table, made from a chipper anvil....so we can now make and use up to 16 inch flat laps instead of chipping trees and petrified trees look really cool polished out.

    LARGER GEMS...THAT has our interest....we would like to be able to facet much larger material than is usually associated with jewelery....We have enough room to brew and attach a big arm....just got too carried away with other stuff....so it got sentenced to the dungeon of CNC parts and supplies.

    My question has to do with holding stones (semi-precious, jaspers, agates, jades, and so forth) onto the large spinning lap....

    1. since we would be creating REALLY LARGE "facet jewels", could not the process be automated and using vacuum instead of DOP?

    2. Using larger facets (pardon incorrect use of lapidary lingo here) and perhaps vacuum, could most stones be faceted without DOP (would not need the precsion, right?) but also by USING TWO OR AT THE MOST THREE MOUNTINGS VIA VACUUM CLAMPING?

    NO DOP...JUST TURN UP THE "VACUUM CLAMP" ON THE ARM.....and use one of the adapted arm designs to be built using existing CNC machine tools, and so forth???

    gadz...just what we need....more unfinished projects in the dark closet of machine tool mystery parts....

    POSSIBLE? or just wheel the sphere machine/monster lap machine into the closet again??? (hmmmm....better make a couple more spheres while it is out...no takers out there for trading laser for driver development, etc.)

    Marc and boyz....
    still holding out for a laser swap....it really works!!!

  11. #11
    Join Date
    Sep 2005
    Posts
    91

    Questions

    Who is we to start with? I suppose you could use a vacume to hold the stone. You could lap oneside by hand to start with and vacume to that side. How large a stone are we talking? Could you post a few pics of the sphere machine? I would like to see it. I have always wanted a sphere machine.

  12. #12
    Join Date
    Nov 2004
    Posts
    320

  13. #13
    Join Date
    Apr 2003
    Posts
    42
    Quote Originally Posted by jhwatts
    Who is we to start with? I suppose you could use a vacume to hold the stone. You could lap oneside by hand to start with and vacume to that side. How large a stone are we talking? Could you post a few pics of the sphere machine? I would like to see it. I have always wanted a sphere machine.
    I will endeavor to post two pictures to this.
    Who is we? Myself, and three sons....the twins are 17 and their younger brother is 10.

    Our question had to do with larger stones....not nec. the kind hanging around a neck.
    Maximum size would have largest measurement of around 2 foot.....smallest facet would have one dimension of perhaps an inch or so....rather large, so they would not be the expensive materials...something that would look cool sitting on a coffee table, or mantle, like the spheres...idea is to show off patterns inside the stone, as well as the clarity of "clear" minerals of other materials.
    The machine with boys photograph is simple two motor sphere machine we made with hand tools about 2 years a go or so...boys are bigger now...but cups used fin photo formed 3 or 4 inch spheres. The two spheres in other photo are about 3 inches in diam. with a black piece of obsidean and the other is petrified wood. We read in the Yahoo Spheres newsgroup. They have other machines in photo section and are a helpful group.
    Attached Thumbnails Attached Thumbnails The+boyz.jpg   obs n wood.jpg  

  14. #14
    Join Date
    Jul 2005
    Posts
    12177
    Marc;

    Have you ever taken a micrometer to the spheres to find out how round they really are? I suspect very good, on the order of thousandths of an inch.

    I have seen these spheres and machines at Rock Hound exhibitions but never near enough to measure even if I did carry a 4" micrometer around.

  15. #15
    Join Date
    Sep 2005
    Posts
    91

    Cool

    Nice machine and nice work. I can’t image trying to facet something 2 foot in diameter. I suppose it would be possible. I have a piece of obsidian that is 19 inches in diameter. I can get all the jasper you want. I can also get very large pieces if needed (up to 2 foot round). I have a piece of Nickel-Iron that is about 20 inches long. I would love to get it lapped on one side. You can view some of my collection at this link.

    http://mathandstuff.freeservers.com/photo.html

  16. #16
    Join Date
    Apr 2003
    Posts
    42
    Quote Originally Posted by Geof
    Marc;

    Have you ever taken a micrometer to the spheres to find out how round they really are? I suspect very good, on the order of thousandths of an inch.

    I have seen these spheres and machines at Rock Hound exhibitions but never near enough to measure even if I did carry a 4" micrometer around.
    Geof
    Well, you made us curious all weekend...so we finally checked one....and in design, it is said that a two motor design makes for rounder spheres, but three motor goes faster. We were in a bit of a hurry when we made it, and just slapped it together with no cnc....figured to do it "right" later...
    Be danged if we didn't come in at under 1 thousand...we will see if one of them in Texas can be measured, but petrified wood can get rather hard...."whodathunkit ?..."

  17. #17
    Join Date
    Apr 2003
    Posts
    42
    Quote Originally Posted by jhwatts
    Nice machine and nice work. I can’t image trying to facet something 2 foot in diameter. I suppose it would be possible. I have a piece of obsidian that is 19 inches in diameter. I can get all the jasper you want. I can also get very large pieces if needed (up to 2 foot round). I have a piece of Nickel-Iron that is about 20 inches long. I would love to get it lapped on one side. You can view some of my collection at this link.

    http://mathandstuff.freeservers.com/photo.html
    cool pictures...
    Biggest reason we are doing CNC related things now is that my poor old body got too banged up to haul it up and down the ropes anymore spelunkings...THAT TRUMPS...

    Point in replying has to do with size when contempating CNC faceting....from our point of view...we prefer about 3 inch spheres or even smaller as it is an interesting way to "see" what is "inside" a sample. I only mentioned a two foot upper size because I would like to do one out of something more homogenious, like obsidian, and then for the challenge...Too big might leave too much "hidden" ??
    We rather like smaller stuff, BUT we are trying to imagine what those of you with experience have already played with. We have some samples that we will only polish as cubes, or triangular pyramidal, and long at that....it all depends on the stone....I imagine some complicated jasper would be visually "jangly" or disturbing if done with too many sides, even if technically excellent....matter of taste I am sure. We like to polish etc. just to compliment what we found when we first licked it....but we be weird....

    Maybe 2 foot is wayyyy too big...one of our goals is to do a two foot jasper or something like that....wanna do a trade perhaps? Many folks do a trade of material for labor....send two chunks, we return one sphere...(no guarantee of 0.001" esp. for 15 inches!!!)

    Is there something we could do to contribute to the discussion of eliminating tedium for faceting or to advance the thread? After tipping over the 24" diamond saw (DON'T ASK!) we are afraid to try a big cut...but....maybe some advise from you all if we did screw it up. WHAT IS THE LARGEST SPECIMUM SOMEBODY HAS A PICTURE OF? IS THERE SOMETHING PARTICULAR DIFFICULT ABOUT VERY LARGE FACETS ? (OTHER THAN TRYING TO STAY AWAKE...)
    wanna think about trading for some big stuff you mentioned? perhaps some of that large jasper and so forth? Post us a note privately as it might not be particularly relevant to large faceting facillitated by CNC, but we are open to it. (sorry for mistakes....falling asleep here)

  18. #18
    Join Date
    Mar 2006
    Posts
    24

    Faceting/Reducing attachment

    This is my faceting, reducing machine for producing veru intricate small
    parts, such as crystal button hob. Machine can be run automatically
    for days, with pick-feed of 0.025mm, resulting surface is smooth.
    Any commend welcome!

  19. #19
    Join Date
    Jun 2005
    Posts
    199

    cnc faceting.

    I have spent many years building and using all types of gem cutting machines.
    Yes I have thought a lot about automating faceting.
    To start in that direction all you would need would be a small stepper to replace the index wheel. Another on the side of the yoke for angles. and one under the post to control the depth of cut.

    This unit could be mounted in the middle of three laps with speed control.
    I don't know that you will ever get away from transfering dops but this is not a difficult process if you use metal dops and an accurate key system.
    This is not to over simplify but rather to provide you with some food for thought
    Hope it helps.
    Incidendally I have almost completed an automatic bead making machine along the lines of a centreless grinder and I am about to use steppers for the cycles on this.
    Bfiles.

  20. #20
    Join Date
    Mar 2010
    Posts
    4
    I try to built a automatic faceting machine. Can anybody help me. I am a german student in mechtronic engineering and have a little shop with cnc milling and turning machines. What kind of software can i use to program the machine and are some pictures from existing projects alive ?

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