Which kind of tumbler is right for you? Each of the two basic forms of rock polisher -- rotary and vibratory -- has its advantages.
Rotary tumblers are an excellent way to get started tumble-polishing rocks. Good-quality tumblers, such as the Lortone models we carry, are much cheaper than comparable vibratory units. Getting good results on rocks that are Mohs 5 or greater in hardness is not difficult, and generally your batch will require checking only once every day or two. You can also tumble-polish metals in these units. Rotary tumblers with rubber barrels -- like the Lortone models -- are also noticeably quieter than vibratory tumblers.
Rotary tumblers are best for producing seaglass.
On the other hand, they take 4 to 6 weeks to produce results. This can be a sizeable disadvantage for some people.
Vibratory tumblers such as the MT-4SV can finish a batch of rocks in little more than a week. Types of appropriate loads are more varied, including very soft organic materials like ivory, with a hardness level down to Mohs 2½. One sort of processing that is possible only with vibratory units is dry polishing.
However, this versatility brings with it a fair degree of complication. Vibratory tumblers are also quite noisy, though this can be moderated to some degree by placing them on a piece of carpeting or other padding.
For many people, the initial high cost of these units is decisive. However, if speed is important to you, then you can process much more rock in the same amount of time with a vibratory tumbler.
So which sort is better for you? It depends entirely on your needs and resources.
Information from How to Tumble Polish Rocks into Gems by Edward E. Smith, and various other sources.