There are two different types of rock tumblers: 1) rotary rock tumblers and 2) vibratory rock tumblers. Each of these has advantages and disadvantages. The best thing that a person can do is to learn about each of them and then make an informed decision.
Rotary Rock Tumblers
A rotary tumbler has one or more barrels that the rocks are placed in. Multiple barrels allow you to tumble
two or more batches of rock at the same time. You can tumble two different types of rock. Or, you can
tumble two batches of rock at different stages of the tumbling process. The barrels are turned by a motor and the rocks tumble inside of the barrel,
rubbing against one another and wearing their way smooth.
A number of companies manufacture rotary tumbling machines. They are the most commonly used type of tumbler.
The photo below shows rotary rock tumblers from (left to right) Lortone, Inc.; Chicago
Electric Power Tools; and Thumler's Tumblers.
The tumblers shown above are made with metal frames, have durable hard rubber barrels and will tumble two or more pounds of rock at a time. They are designed to give years of reliable service if they are cared for properly. Also sold are plastic tumbling machines. These plastic tumblers cost a little bit less and are designed to tumble a small handful of rocks at a time. These lower-priced machines can last through a few batches of rocks if you are careful and do not overload them. They are suitable purchases if you simply want to try the rock tumbling experience and move up to a "real tumbler" if you enjoy the activity. We recommend buying one of the better tumblers at the start if you know that you will continue with the rock tumbling hobby.
Vibratory Rock Tumblers
Vibratory tumblers have a bowl instead of a barrel. Rocks, grit and water are loaded into the bowl, covered, then allowed to vibrate. This vibrating action causes the rocks and grit to smooth the rocks. Shown below are vibratory tumblers from (left to right) Johnson Brothers and Thumler's Tumblers.
Which one should you buy?
The type of tumbler that you should buy depends upon the types of material that you will be tumbling, how fast you need results and how much rock you have to tumble. Here are some advantages and disadvantages of each.
| |
Advantages |
Disadvantages |
Rotary |
* Very easy to use
* Lower cost than a vibratory tumbler
* Shapes rough into rounded stones |
* Difficult to polish fragile rocks
* Each tumbling step takes at least one week
* Requires more grit and polish
* Occasional leaks |
Vibratory |
* Tumbling takes a few days per step
* Requires less grit and polish
* Gentle action polishes fragile rocks
* Does not leak |
* Rough rocks receive minimal shaping
* More expensive |
In summary, if you are starting out with crushed or hammer-broken rocks
with jagged edges and desire tumbles that are nicely smoothed and rounded then a rotary tumbler is
best for you. A vibratory tumbler does not do a lot of shaping so if you put in angular rocks your finished product will be angular tumbles. On the other hand, if you are working with pre-shaped
rocks (such as beach stone or cut cabochons), thin slabs, or very delicate
material such as glass or obsidian then a vibratory tumbler would be more
effective.
Also, if you opt for a rotary tumbler, purchasing a double-barrel tumbler is
helpful in reducing tumbling time. Two barrels allow you to simultaneously tumble rocks
in two different steps of the tumbling process, or rocks of two different hardnesses.
