Harbor Freight Tools 90979 - Manual (Page 4)

SKU 90979 For technical questions, please call 1-800-444-3353. Page 4
Unpacking
When unpacking, check to make sure all of the parts on page 8 are
included. If any parts are missing or broken, please call Harbor Freight Tools at
the number on the cover of this manual as soon as possible.
How a Rotary Tumbler Works
The motion in the Barrel of a Tumbler simulates the natural action of flowing water or
ocean waves. Beaches and riverbeds contain rocks and pebbles smoothed by water and the
abrasive sand it carries. As rocks grind upon one another with constant water and sand in the
mix, they begin to round and smooth. Although this is a constant process, it does not however,
naturally polish the rocks.
The Tumbler uses an abrasive media instead of sand. It is graded by grain size, from
fine powder sized grains, up to large sized grains. By changing (usually by weekly intervals)
the grain size, rotating from coarse, medium, to fine, the rock or gemstone is smoothed much
more quickly than the natural process.
To polish using a Tumbler, you add a metallic oxide compound (see step 4 on page 5).
The complete process for a gemstone or rock to go from rough to a smooth, polished finish,
usually takes from 4-6 weeks.
Operation
I. Location
Note: The Tumbler will be working 24 hours a day for several weeks at a time, and needs to
be in a convenient and safe location that will not interfere with family activities. It
generates a slight humming sound. The motor becomes hot to the touch. This is
normal.
1. Make it accessible. You will need to open it daily, in some cases.
2. Locate it near a power outlet. It must be located in an open area that is away from any
flammable materials. Do not use the Rotary Tumbler outdoors.
3. Do not put the tumbler on a table. The vibration of the unit may cause the tumbler to
crawl when placed on a smooth slippery surface.
4. Only use the tumbler in an extremely safe location such as a concrete garage floor.
5. Do not put it in a closet or drawer as it has a fan cooled motor and needs proper
ventilation.
6. Do not let it freeze, as the water in either of the Rubber Barrels (22) will freeze and
become unbalanced, overloading the motor. Avoid extreme temperatures.
7. It is possible for one of the Rubber Barrels (22) to break open and spill. Make sure the
location is safe for that possibility.
Caution: Always check on the tumbler on a regular basis to make
sure the unit is running properly and is not overheating. Make sure that