I am often asked the question of which type of tumbler is better--rotary or vibratory.
The real question people should ask is "what type of rocks do I want when I am finished?"
A good rotary tumbler (Thumler's or Lortone) will take your rough stones and make them beautiful rounded, polished gems. A vibratory type tumbler (Thumler's) will take your rough stones and polish them only. Vibratory type tumblers do NOT round or shape the rock. Whatever shape you put in is the polished shape you will get out.
"So why get a vibratory tumbler?" you ask. They have a very useful purpose. They don't change the shape of your stones. If you have stones that you have cut and ground to a specific shape and you want to polish a lot of them at once, then you can use a vibratory tumbler. This is great if you have made a lot of pre-formed cabs and want to polish them without changing the shape. I know a lady who cuts out little dinosaur shapes from slabs on a diamond band saw, and then fills her vibratory tumbler to polish all the dinosaurs at once. This process will save her a lot of time and money in the long run.
Another advantage with a vibratory tumbler is that they only take 7-10 days vs. 30-45 days with a rotary tumbler. The trade off is that vibratory tumblers are usually a lot more expensive.
There is another type of tumbler on the market that I am often asked about. That is the -sonic type tumblers. These type use ultrasonic vibrations to create the action that polishes the rock. Once again, they are like a vibratory tumbler except they tend to not last long, as the transducers are easily broken with prolonged use.
If you have other questions, e-mail me at firstname.lastname@example.org, or call 1-888-Rock-Shop (1-888-762-5746).