Message #205011

[lithicbeads]

 Most commercial cabs including circles are cut on a semi automatic machine that rotates the dopped cab into  a grinding wheel incrementally until it matches the model attached to the machine. Some folks put the dopped cab in a nattery powered drill gun and while handholding it run the edge slowly into the wheel. After the girdle is done you can slowly rotate the stone towards the top and crown it as well. Incresing the speed as the girdle preform becomes quite round will help make it better if you hold the drill carefully. Minute hardness differences in the stone lead to the small asynetries you are referring to in many cases but the way our hands rotate can also make a perfect circle very difficult when hand cutting. Obviously no stone circle is perfect but I hope you get some to the point they do not bother you. I have a very similar problem  when looking at certain shapes.