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Large tumbler to hold 50 pound

Jewelry Discussion
#1

I would like to contact some dealers who have used or still use a
large size tumbler. I have a homemade tumbler that uses two 5 gallon
buckets for barrels. The rough grits down to the 220 grit work OK but
I don’t get a good polish even when I go with a long fine grit and
then a cerium polish. What I would like to get is some first hand
and ideas from experience. Since I am looking at the
rolling barrels I would like this for comparison.

How loud is it when running?

How long does it take for a good rough grind? (Does it usually take
two times with rough (36-90) grit to get the rounding done?)

How long does each other grit runs take to get the batch ready for
the next grit?

What proportion of “fist size” rocks can be put in each load and have
the load all come out in good polish?

Does the hex barrels work better than the round barrels? (From your
view.)

How much 36-90 grit is used per load (50 pound load or what ever your
tumbler holds.) And for each grit size after this.

I will have other questions I am sure but this is a start.

I have some catalogues from people like Covington, Star Diamond, but
have not seen a lot of available until the machine is
purchased. I would like the so I would be informed before
I either go buy a new commercial tumbler or do a major remodeling job
on my homemade tumbler/

Larry E. Whittington

#2

Howdy Larry,

I'm including a link to asite that has instructions for building

large tumblers.(truck tires #50) Also, I believe Home depot and
perhaps other similar stores carry fairly inexpensive cement mixers
(Chinese?)that could maybe be converted to large tumblers.
http://www.acc.umu.se/~widmark/lwtrumld.html Carl
1 Lucky Texan

#3

Regarding the truck tire tumbler, I’m all for innovations and this is
clever and cheap but I can quickly think of a serious problem: Have
you ever tried to dump water out of a tire? It’s difficult at best
because no matter how you move it, the water just sloshes around to
the bottom. The last quart of water has to be splashed out by throwing
the tire up in the air and letting it smash onto the ground – and
still it takes a few times doing this to accomplish a more or less
empty tire. This design, it seems to me, would mean that you couldn’t
easily clean it between charges of varying grit (perhaps solved by
haveing different tires for each stage); you’d have to scoop out the
last bit of stones each time, rather than simply dumping it on its
side.

One advantage though is that you could easily reach in and pick out a
piece to observe the progress because there’s no lid. It could be a
useful tumbler for finishing brass or base metal castings in volume,
tumbled in abrasive ceramic media where the objective would be a satin
finish. . . still, you’d have to scoop and pick out the last of it.
Alan Heugh

http://www.nas.com/~aheugh/

#4

Hi Alan,

Regarding the truck tire tumbler. It may be possible to eliminate the
’hard to remove water (and anything small)’ problem. One way is to
drill a relatively large, about 2 inch, hole in the center of the tire
tread. Then plug the hole from the inside with a rubber stopper. Get
one that doesn’t protrude beyond the tread on the outside. In the US,
there are stoppers available (in many sizes) that have a metal top &
bottom with a screw going through the center. When the screw is
tightened, it compresses the rubber causing it to bulge out, holding
tightly to what ever is constraining it.

Dave

#5

Hi Alan,

Regarding the truck tire tumbler. It may be possible to eliminate the
’hard to remove water (and anything small)’ problem. One way is to
drill a relatively large, about 2 inch, hole in the center of the tire
tread. Then plug the hole from the inside with a rubber stopper. Get
one that doesn’t protrude beyond the tread on the outside. In the US,
there are stoppers available (in many sizes) that have a metal top &
bottom with a screw going through the center. When the screw is
tightened, it compresses the rubber causing it to bulge out, holding
tightly to what ever is constraining it.

Dave

#6

from what i gathered in reading the text about the 50 lb tumbler they
just use 60 grit and never clean it. this would mean you would need
other tumblers to finish with, as the article states.

#7

Hi,

I use a tumbler I built that is the bottom 1/3 of a 45 Imperial (55
US) poly barrel attached to a shaft at about a 45 degree angle (much
like a cement mixer). My use is for rounding off the edges of slabs
and taking the saw marks off - generally to give them a more natural
look. It holds approximately 50 lbs per load.

The critical aspect of tumbler design is the speed the barrel
rotates. Too fast you will either get too aggressive cutting action
and damage from the rocks chipping each other or you will have the
rocks held against the outside of the barrel and nothing happening. To
get a rough idea of how fast the barrel should rotate - time a hobby
type tumbler (Lortone etc.) - then calculate the surface speed that
the outside of the barrel travels at. For the barrel I run my
reduction is approximately 30 to one - getting the barrel turning
about 60 rpm - which is good for the rough stage but may be a bit fast
for the polish cycles.

Also you may want to include either a bunch of small stones in your
mix or plastic pellets - helps cut down on the impact of the rocks
against each other. You also have to only load the tumbler about 3/4
full or there will be no room for the material to tumble.

How loud is my contraption when it is running? Well lets put it this
way, it lives at the end of 100 foot extension cord and is not run
after dark, and that is with a plastic barrel.

I was finding I could round the corners of the slabs (Moh hardness of
about 4.5) and remove any saw marks in less that 16 hours. It would
take a bit longer to get rough pebbles to smooth out. I just add a bit
more grit to the load when the cutting action seems to reduce.

The rest of your questions are not too specific to the process I use
my tumbler for but drop me a note if you would like more details on
the design or some of the research I did in building it. I am not
quite happy with the longevity of the poly barrels so I may resort to
building some neoprene lined steel ones.

Thanks, Cameron Speedie Island Gem and Rock
@Islndgem

#8

Dave Arens’ idea for a hole and a plug certainly would help,
nevertheless, if I wanted to make a big tumbler I’d try something on
the order of a cement mixer setup with a barrel that you could tip
over on a frame with pivots. There are used 55 gallon plastic drums
that can be had for about $10 each. This is all hypothetical for me, I
don’t believe I’ll be making anything in that sort of volume, but it’s
fun to think about. Alan Heugh

http://www.nas.com/~aheugh/