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Covington Tumblers

CHOOSING A TUMBLER

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 trying 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.
 

MAINTENANCE

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!