Two types of tumblers are used by most hobbyists: 1) rotary rock tumblers; and, 2) vibratory rock tumblers. Each of these has advantages and disadvantages. If you want to buy a rock tumbler or a rock tumbler kit, the best thing that you can do is learn about each of them and make an informed decision.
There are also inexpensive tumblers made to introduce children to the hobby. These kids tumblers have plastic barrels - they make a LOT of noise and will wear out quickly - but they have a lower price.
For beginners we recommend a hobbyist-quality rotary tumbler with a metal frame and a soft rubber barrel. They cost a bit more but they run quietly and will last for years.
In summary, rotary rock tumblers are the most popular. They have the ability to transform angular rock fragments into rounded rock fragments in five to six weeks. In contrast, vibratory tumblers do little to alter the shape of the rock, instead they are more efficient at smoothing the surfaces of the rock quickly - they require about one to two weeks to process a batch of rock. So, if you want nicely rounded stones get a rotary machine. If you want angular stones get a vibratory machine.
Rotary rock tumblers are typically less expensive than vibratory tumblers. Expect to spend at least $80 for a small rotary tumbler with a rubber barrel or about $200 for a small vibratory tumbler.
The best of both worlds is to process the rocks in a rotary tumbler for the coarse grind to achieve a rounded shape. Then use the vibratory tumbler to quickly do the fine grind, pre-polish and polishing steps.
What Are 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 at the top right of this page shows rotary rock tumblers from (left to right) Lortone, Inc., and Thumler's Tumblers. We own several Lortone tumblers and two Thumler's tumblers and recommend both of these brands.
The tumblers shown are made with metal frames, have durable 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.
Plastic tumbling machines for children are also sold. These plastic tumblers cost less and are designed to tumble a small handful of rocks at a time. These plastic-barrel tumblers make a LOT of noise and will last for just a few batches of rock if you are careful and do not overload them. They are suitable purchases if you simply want to introduce a child to the rock tumbling experience and move up to a "hobbyist's tumbler" if the activity is enjoyed. We recommend buying a full-size rotary tumbler with a metal frame at the start if you know that you will continue with the rock-tumbling hobby.
More about rotary tumblers.
What Are 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 friction between the rocks and grit and results in rocks with smooth surfaces. The action in a vibratory tumbler does little to round the shape of the rocks. Vibratory tumblers can process a load of rocks in about 50% of the time required by a rotary tumbler. Shown in the photo at the top of this page 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.
Very easy to use - best for beginners.
Lower cost than a vibratory tumbler.
Shapes rough into rounded stones.
They run quietly if you get a rubber barrel.
Each tumbling step takes about one week.
Requires more grit and polish.
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.
A bit more challenging to use.
More noise than a rubber-barrel rotary machine.
Vibrations! They can "walk" or shake the building.
Some must be attached to a weight or to the floor.
In summary, if you are starting out with crushed 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.
There are two basic types of rock tumblers: rotary tumblers that process the rocks in a rotating barrel and vibratory tumblers that process the rocks in a vibrating bowl or barrel. The rotary tumblers at top are made by Lortone and Thumler's. The vibratory tumblers on bottom are made by Thumler's and Lot-O-Tumbler.
This video explores the differences between rotary and vibratory tumblers and suggests a method of tumbling that takes advantage of the strenghts of each type of tumbler.
Rock tumbling kits are a very popular and easy way to get started. Most kits include the tumbler, grits, polish and rough. The machine above has a metal frame which will last a long time. It also has rubber barrels which will run quietly.
Photograph of a "Rolling Stones" rock tumbler by Natural Science Industries, Ltd. This is an example of an inexpensive rock tumbler for children. The frame and the barrel are made of plastic - they make a LOT of noise. They are durable enough to process a few small loads of rock. They can be purchased for under $50.