A Diamond Is Forever

After I completed my Rotary Table (RT) angle plate fixture, I got to thinking about some projects that I could do with it. The ability to have precision access to another couple of axis is empowering. We all know X, Y and Z axis, but I don’t know if there is a term for these additional ones, so I’m calling them Axis R (rotation) and Axis RA (rotation + angle). Feel free to correct me if I’m wrong.

My wife and I like to frequent local gem shows (her jewelry/me rocks). I’ve always admired the craftsmanship that goes into cutting gemstones. I thought that the RT w/ Angle Plate should make it possible, so I decided to try and cut my own Diamond.

I had a leftover piece of 2” aluminum round bar and I thought that it would be a good starting point to practice on. I did a lot of research to find anything I could on diamond cutting. I needed angles, sizes, proportions, sequencing, lapping and polishing techniques. I found some great information in a gemologist club newsletter that gave me everything I needed. From there I figured out their lingo and formulas and I made a plan. I figured out a way to reliably hold the piece so I could accurately cut the 73 facets, a simple indexing system to retain continuity from end to end, and finally a way to finish it. Aluminum is so soft; you really have to be careful not to lose the crisp edges.

I included some build and finish pics, and the spec sheet I used with all of the info. I hope you like it.

Factiod: I calculated the weight of my diamond based on the specific gravity of aluminum and dimensions and it comes to about 450 Karats. A real diamond of the same size, cut and weight would cost 2 to 200 million dollars depending on the color, clarity, etc..

Fabrickator,

Absolutely brilliant! I can't wait to see you make one from cubic zirconia! Thanks for sharing.
Tormach calls the rotational axis the A axis but I don't know if that is convention.

Awesome, its looks as if all the meets are perfect.

WOWSER !!! That be cool man.

Chuck the grumpy old guy

Wow! Your brilliance is showing!!!

-brino

That's super duper, Fabrickator.

VERY impressive

Diamonds don't last forever on a surface grinder!

Very nice work

Nice work, hard to believe that people do that with a little stone. Great use of an excelently designed tool.

Thanks guys. It was a fun and mentally challenging project. Like I told my wife, it ended up being an exercise in concentration. I also learned a lot about cutting gemstones that I may actually try someday, when I can't stand up for hours on end at the machines anymore.