Christopher Tidy wrote:

DeepDiver wrote:

"Christopher Tidy" wrote in message
...

I woke up in the night and it occurred to me that a stone
polisher (or rock tumbler as some people call them) would
make a great home shop project.

I figure I can make a drum (probably cube-shaped) from
welded 1/4" plate. The drive is going to be more of a
challenge (I don't have a great deal of cash to spend on
this).


I remember seeing plans for a DIY rock tumbler many, many years ago in
my childhood subscription to Popular Mechanics. But there's a huge
price difference between consumer commodity products of back then and
of today. I strongly suspect that you could buy a decent-quality used
one off Ebay (or a cheap new one for $20 from Harbor Freight) for the
same amount of money -- or less -- than building one yourself (by the
time you factor in the costs of all the materials, parts, and
fasteners -- not to mention your time and labor). Unless you are
really looking for a new home project to undertake.

If you do decide to build one yourself, you won't want to make the
drum out of steel (or any other metal) and you certainly don't want it
to be a cube:

1. Steel is too hard and would cause the stones to fracture and scratch.
2. Aluminum also would not provide enough cushioning (and might get
embedded with abrasive).
3. Even if breaking and scratching is not an issue, a metal drum would
be very noisy.
4. A cube shape is too "angular" a geometry: the stones would tumble
too violently and fracture or scratch.

Ideally, what you want is a rubber drum that has an octagonal profile.
The stones should be rolling and sliding against each other (not
dropping and crashing), with the octagonal sides providing just enough
tumbling action. If you must make a drum out of metal, you'll probably
want to glue rubber sheet all over the inside. (Of course, then you
have to worry about abrasive getting trapped in the seams. Remember,
you will need to progress from course to medium to fine to polish.)

Even if I were going to make my own tumbler base station, I'd probably
still buy the hard rubber drum.

Btw, tumblers can also be used for deburring, derusting, and cleaning
small metal parts.


Thanks for the message. It's so long since I looked into this subject
that I'd forgotten about the need for abrasive. I thought you just put
the stones in and let them tumble together. My idea might also be partly
based on my recollection of a concrete mixer with a specially made steel
drum used for smoothing and cleaning flame cut metal parts at a place
where I had a summer job once. But I really did intend it as a home shop
project (i.e., one in which much of the fun is to be had in the
construction). I also suspect I'd get something of a rather higher
quality than the consumer products, which look a little plasticky to me!

Best wishes,

Chris

Check out how it is done. Might surprise you. And a source of supplies.

Here is one I found: [ I have no contact with these or this person.)
http://www.rocks4u.com/

Martin
--
Martin Eastburn
@ home at Lion's Lair with our computer lionslair at consolidated dot net
NRA LOH, NRA Life
NRA Second Amendment Task Force Charter Founder

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