New addition to the tool stable. An old lathe
(1946 South Bend 9", Model A)
for manufacturing grinding/polishing cups!
How to create a sphere
1- Find a suitable rock.
2 - Use saw to create rough pre-form.
I use a device that allows for even, indexed cuts which helps in the initial shaping.
3 - Take the polygonal shaped rock and run it on a grinding wheel to knock down the high spots.
(The more time you take here makes for quicker rounding.)
4 - A pipe fitting (1" - 1-1/2" bell fitting shown) with diamond embedded brazing rod applied makes the initial round pre-form.
5 - Diamond pads glued to pipe fittings are used in the polishing of the sphere.
These diamond pads are available from 30 grit to 10,000 grit (buff). This set I built myself.
6 - Display your spare!