Facet Machine

[Marc Soren]

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.

[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.

[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

[Marc Soren]

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 ?..."

[Marc Soren]

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)

[kkilst]

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!

[wjfiles]

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.

[KRainer]

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 ?