Covington's Rolling Tumblers are stout American-made machines built to last. Our Rolling Tumblers feature a solid EVA barrel. These quiet running units utilize raised ridges inside the barrel which prevent sliding and promote a faster grind. The proper rotary speed is preset in factory to ensure maximum abrasion and polishing action.Units are powder coated for durability and longevity. The steel support shafts are cushioned by nylon bearings. The barrel rests on the steel supports and lifts off for easy inspection and cleaning. The steel support shafts are cushioned by nylon bearings and are supported in the middle to ensure that the shafts do not bend from the weight of the barrels. The barrels rest on the steel shafts. This unit ships complete with a small sample of Old Miser, instructions, and a product guarantee.
Solid EVA barrel Cast aluminum and steel chassis Heavy duty cast aluminum construction Powder coated frame and belt guard for durability and longevity Solid 1/2" steel support shafts DuPont nylon bearings Fan cooled motor Limited 220V, 50Hz availability. All others work perfectly with a voltage transformer!
251TUM - 1/21hp Motor, Single Gallon, 12 lb. capacity
Covington's Tumblers are designed for tumbling small to medium sized stones, gems, glass, jewelry castings, coins, bullet casings, and other small objects. The Roll-N-Tumble Gem Tumblers feature solid EVA barrels with two raised ridges to promote the grinding process by causing the media to fold over on itself instead of sliding down the barrel's side. These barrels are available in three sizes: one gallon, one half gallon, and one quart. Machines are available in sizes ranging from single barrel to triple barrel in each barrel size. Additional barrels are available for purchase and the larger units allow for you to mix and match barrel sizes. For instance, a double gallon tumbler will accommodate two gallon barrels, three half-gallon barrels, several quart barrels, or a mixture thereof. Some people like to have a barrel for each step of the grinding process which allows them to inspect their pieces and move them on to the next step without eliminating all of the grit from the first process.
Using a Tumbler
When tumbling, fill the barrel approximately two-thirds full of stone. For a one-gallon barrel, use about a cup of grit and a couple of tablespoons of Old Miser; increase or decrease proportionally according to barrel size. You want your tumbling media to be a slurry. This will appear to be the consistency of a thin hand cream. Keeping your media at this creamy state will ensure maximum grinding. This is merely a suggestion, not a hard and fast rule for tumbling. The best way to ensure you are receiving maximum effect for your tumbling is by keeping record of your tumbling process. Keep record in a journal noting the amount of grit you use, what type of grit you used, amount of water, how much stone, what kind of stone, et cetera. This will ensure that future tumblings are more effective. The best way to learn tumbling is by trial and error. Keeping notes allows you to remember exactly what worked and what didn't and how you can be better prepared for future tumblings.
Tumbling is a fun and easy way to grind and polish gemstones. Always remember to place pieces of equal or similar Mohs Hardness in the tumbler. If you mix stone hardnesses, you will find that the hard stones have not tumbled well and the soft stones have been ground down to nothing. A simple test for checking hardness is taking an iron wood nail and tying to scratch your stone. Iron is a 5 of the Mohs Scale and will scratch anything softer than a 5 but will not leave any mark on a stone harder than a 5.
When placing the barrel lid back on the barrel, make sure that the clamp is tightened around the top where the lid fits into the barrel's neck. If the clamp is tightened lower than the lid it can lead to premature wearing of the neck and possible leaking from the lid area. Please note, these barrels are a consumable item and wear out over time. They are not covered under warranty except if they are defective. These barrels tend to blacken over time. There is no way to prevent this from happening. Regularly maintain your tumbler by greasing nylon bearings on each side where the shaft rests in the aluminum casting. You can use marine grease or white lithium grease, both should be available at your local hardware supply store. Covington's tumblers are designed and built to last you a lifetime!
Covington sells a few different starter grit and polish kits so you can start tumbling. Each kit comes with a coarse grit (60/90), a medium grit (120/220), a fine grit (3F-400), Old Miser compound to mix with the grit and form a slurry, and Covington Tumbler Polish. These kits are available in several sizes to suit your needs. Smaller tumbler units will require less grit to complete a tumbling cycle, therefore you may choose to purchase either the Starter Grit & Polish Kit or the Tumbler Grit & Polish Kit which have smaller amounts per kit. A larger tumbler such as a 40 lb. Production Tumbler would require more tumbling media. Choosing a larger grit kit such as the Jumbo Grit & Polish Kit might be the most economical choice. The Tumbler Grit & Polish Kit will provide approximately one complete tumble cycle for a one-gallon tumbler so plan accordingly. Covington’s Tumbler Polish polishes a small percentage of stones. It is typically used as a “pre polish” rather than a final polish. We highly recommend Covington’s “Gold Polish” series for achieving a final tumble polish. Depending on what material you’re tumbling, you may also consider purchasing a pound of plastic pellets. These pellets are used during the polishing cycles; they act as a cushion when tumble polishing to help prevent fracturing of stones. The pellets will float to the top in water and can be scooped out, rinsed, and reused repeatedly.