I just started the first run this morning. I got a jar full of small pebbles and divided them in half by hardness. I put each pile into a tumbler and started it up. I didn’t think to take a picture of the stones before putting them in (silly me). I will next time.
The plan is to do four stages about a week long with four different grades of sand in the machine.
I am making a machine that can hold four tumblers. The idea is that I can graduate the rocks individually to the next level. I think that will reduce labor. So instead of rinsing and cleaning the rocks and reloading the machine, I just pull whatever stones out from one stage, run water over them and then drop them into the next stage (probably wash them over the tumbler before to keep recycle the grit).
I managed to find a good supplier of sand/grit and have four grades on hand.