Petrified Colla Wood Sphere - Updated 9-8-17, Completed

I missed that RTH now has a section specifically for sphere making! I have been cutting spheres off and on for about two years. I hadn't been cutting many because the waste breaks my heart lol I am lucky that I met someone who has been making spheres for 30 years. He and I have become good friends and he has been teaching me what he has learned over the years.

I have been preforming on the saw using an angle jig. Once all the cuts are made, an angle grinder to cut off the points and round the preform. From what I have been reading here, that seems to be the norm.

I have two spheres I am currently working on. The first is Gneiss with hornblende and garnets from Austria. I didn't take photos of the rough or any of the stages to get to this point. I didn't know we had this forum =\

I need to measure it but I think it is right around 2". This is after all the preforming and angle grinding.


A shot of it wet


This second is petrified "colla" wood. I don't have a photo of the rough piece but it is cut from a 15lb chunck. I am shooting for a 4" finished sphere. This is "the cube".





This is some of the "scrap" from preforming the cube.
This piece is 6 1/2" long and has the golden/yellow and tourqouise all the way through it. Unfortunately it was on the thinner end of the rough.  would have liked to capture some of it in the sphere. I debated making two 1-1/2" spheres but decided the cabs it will make are going to be more fun.


If it weren't for this piece I would have gone for a 6" sphere. There was a fracture in the rough that opened up a bit further after the second cut. When I was turning it I tapped it twice with a hammer and this peice calved. There was saw oil all the way through. I was surprised it hadn't come off in the saw.


One of the slabs I cut after making the first "face" cut. I had a hard time making the decision to move forward with the sphere after this cut lol
Side 1

Side 2


I made the other cuts and am ready to start grinding off points. I will try to remember to take more progress photos.

Update 8-22-17

photos showing the preform after all 26 cuts made. The pictures were taken in direct sun and aren't the best.









It is looking to come in right around 3.75" when finished.

The next step is to grind it down to round.

Update 9-8-17

I broke out the angle grinder and ground down my preform this week.





Thursday a new toy arrived..


I bought a HP High Speed Sphere Machine (HSSM).


Setup was easy, though the thing weighs a ton.



In 45 minutes I had it setup, cups on, and grinding.


This is the preform after 15 minutes on coarse.

Still has a few flat areas so it will need to go back to coarse.



After another 10 minutes on coarse, I did 5 minutes on 400, 5 minutes on 800, 2 minutes on 1200, and 10 minutes on a low speed machine with cerium oxide.








The sphere finished out at 3.8". Total time from preform to completed sphere was about an hour with the HSSM. The machine is a beast.

Roger