Hi all,

When I was about 8 or 9 years old I really, really wanted a stone
polisher. I think they were rather expensive and also (probably wisely)
my parents thought that I would be bored having to wait months for
results, so I didn't get one for my birthday. Anyway, 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 reckon I probably need about a
30 rpm drum speed and 50 W of power for a small polisher. But the drive
needs to be sturdy and energy efficient if I'm going to leave it running
in the shed all year. A mulit-stage belt drive will be fiddly and
probably not very energy efficient. It seems to me that the best
solution would be an oil-filled worm and wheel gearbox, but I'm not sure
where to scrounge one from. Can anyone think of pieces of industrial
equipment which use a suitable gearbox, which I could look out for in
piles of junk etc? Has anyone built one of these before? Any ideas would
be welcome.

Best wishes,

Chris

"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.

- Michael

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

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 suggesting eBay. I just had a look at a few machines on
there. The way in which the drum is supported on smaller rollers solves
the gearing problem rather neatly.

Chris

On Thu, 19 May 2005 07:19:13 +0000 (UTC), 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 suggesting eBay. I just had a look at a few machines on
there. The way in which the drum is supported on smaller rollers solves
the gearing problem rather neatly.

Chris

A local gentleman uses a 55 gallon drum with flanges welded inside to
provide a tumbling action, sprayed with bed liner for longevity. He
has it attached to the counterweight arms of a pumping unit here in
the oil fields. He can tumble a **** load of rocks at one time, for
little or no money G

Rather impressive how well it works.

Gunner

"Pax Americana is a philosophy. Hardly an empire.
Making sure other people play nice and dont kill each other (and us)
off in job lots is hardly empire building, particularly when you give
them self determination under "play nice" rules.

Think of it as having your older brother knock the **** out of you
for torturing the cat." Gunner

Hi Chris:

Dan Williams' pyrotechnics site:

http://www.wecreate4u.net/dwilliams/top.html

The ball mill is beautifully described under "tools" but there's so
doggone much interesting information elsewhere that you'll want to look
at everything. Giant fountains, giant sparklers, homemade balance
scale, etc., etc.

Best regards -- Terry

Big old probably obsolete copy machines the kind it would take a few
strong men to carry have some great strong gearmotors in them.

One standard 5- or 10-gallon propane tank, empty, flushed etc
Cut a square door in the side, hinge it, add a hasp or something to keep
it closed.
Line it with rubber sheet, held with good contact cement. The spray
bedliner might also work, you can get in in aerosol cans at any parts store.
Support it on a "Vee-block" of 4 inverted wheels - the stationary ones
that are used with casters.
2 additional angeled wheels at the ends keep it from moving axially.
Any small electric motor with a very small-diameter pulley on it.
Belt runs around the outside of the tank between the door and the top
(or bottom). Use a long thin flat serpentine belt. Might need a simple
spring tensioner.
Add rocks, carborundum power.
You'd probably want to tape the door after filling to make sure you
didn't leak carborundum all over the place.
- -
Rex Burkheimer
WM Automotive
Fort Worth TX

Christopher Tidy wrote:
Hi all,

When I was about 8 or 9 years old I really, really wanted a stone
polisher. I think they were rather expensive and also (probably wisely)
my parents thought that I would be bored having to wait months for
results, so I didn't get one for my birthday. Anyway, 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 reckon I probably need about a
30 rpm drum speed and 50 W of power for a small polisher. But the drive
needs to be sturdy and energy efficient if I'm going to leave it running
in the shed all year. A mulit-stage belt drive will be fiddly and
probably not very energy efficient. It seems to me that the best
solution would be an oil-filled worm and wheel gearbox, but I'm not sure
where to scrounge one from. Can anyone think of pieces of industrial
equipment which use a suitable gearbox, which I could look out for in
piles of junk etc? Has anyone built one of these before? Any ideas would
be welcome.

Best wishes,

Chris

So is there a consensus about how many RPM the barrel that holds the stones
(or in my case, old bolts from a project car) should be turning?

Peter

"Christopher Tidy" wrote in message
...
Hi all,

When I was about 8 or 9 years old I really, really wanted a stone
polisher. I think they were rather expensive and also (probably wisely) my
parents thought that I would be bored having to wait months for results,
so I didn't get one for my birthday. Anyway, 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 reckon I probably need about a 30 rpm drum speed
and 50 W of power for a small polisher. But the drive needs to be sturdy
and energy efficient if I'm going to leave it running in the shed all
year. A mulit-stage belt drive will be fiddly and probably not very energy
efficient. It seems to me that the best solution would be an oil-filled
worm and wheel gearbox, but I'm not sure where to scrounge one from. Can
anyone think of pieces of industrial equipment which use a suitable
gearbox, which I could look out for in piles of junk etc? Has anyone built
one of these before? Any ideas would be welcome.

Best wishes,

Chris

Peter Grey wrote:
So is there a consensus about how many RPM the barrel that holds the stones
(or in my case, old bolts from a project car) should be turning?

30 rpm was just my guess while I was thinking about a design this
morning. Having done a little more searching online I've found two
commercial models which run at 45 and 52 rpm, so this gives a rough idea.

Chris

Gunner wrote:
On Thu, 19 May 2005 07:19:13 +0000 (UTC), 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 suggesting eBay. I just had a look at a few machines on
there. The way in which the drum is supported on smaller rollers solves
the gearing problem rather neatly.

Chris


A local gentleman uses a 55 gallon drum with flanges welded inside to
provide a tumbling action, sprayed with bed liner for longevity. He
has it attached to the counterweight arms of a pumping unit here in
the oil fields. He can tumble a **** load of rocks at one time, for
little or no money G

Rather impressive how well it works.

Nice idea. Do you have any pictures of the contraption? I'd love to see.

Chris

I'd expect 4 - 10 RPM would be about right. Slow enough to allow
sliding, fast enough to induce some tumbling.
Get a variable speed motor.

- -
Rex Burkheimer
WM Automotive
Fort Worth TX

Peter Grey wrote:
So is there a consensus about how many RPM the barrel that holds the stones
(or in my case, old bolts from a project car) should be turning?

Peter

"Christopher Tidy" wrote in message
...

Hi all,

When I was about 8 or 9 years old I really, really wanted a stone
polisher. I think they were rather expensive and also (probably wisely) my
parents thought that I would be bored having to wait months for results,
so I didn't get one for my birthday. Anyway, 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 reckon I probably need about a 30 rpm drum speed
and 50 W of power for a small polisher. But the drive needs to be sturdy
and energy efficient if I'm going to leave it running in the shed all
year. A mulit-stage belt drive will be fiddly and probably not very energy
efficient. It seems to me that the best solution would be an oil-filled
worm and wheel gearbox, but I'm not sure where to scrounge one from. Can
anyone think of pieces of industrial equipment which use a suitable
gearbox, which I could look out for in piles of junk etc? Has anyone built
one of these before? Any ideas would be welcome.

Best wishes,

Chris

Christopher Tidy wrote:

Hi all,

When I was about 8 or 9 years old I really, really wanted a stone
polisher. I think they were rather expensive and also (probably wisely)
my parents thought that I would be bored having to wait months for
results, so I didn't get one for my birthday. Anyway, 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 reckon I probably need about a
30 rpm drum speed and 50 W of power for a small polisher. But the drive
needs to be sturdy and energy efficient if I'm going to leave it running
in the shed all year. A mulit-stage belt drive will be fiddly and
probably not very energy efficient. It seems to me that the best
solution would be an oil-filled worm and wheel gearbox, but I'm not sure
where to scrounge one from. Can anyone think of pieces of industrial
equipment which use a suitable gearbox, which I could look out for in
piles of junk etc? Has anyone built one of these before? Any ideas would
be welcome.

Best wishes,

Chris

http://www.herbach.com

Great stuff. I haven't ordered from them in 15 years, but they were
good solid people the last time I dealt with them.

--
-------------------------------------------
Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

So is there a consensus about how many RPM the barrel that holds the stones
(or in my case, old bolts from a project car) should be turning?

30 rpm was just my guess while I was thinking about a design this
morning. Having done a little more searching online I've found two
commercial models which run at 45 and 52 rpm, so this gives a rough idea.

RPM must depend on size.

i

True. My figures were for machines with drums of around 6" to 8" in
diameter.

Chris

On Thu, 19 May 2005 16:14:26 +0000 (UTC), Christopher Tidy
wrote:

Gunner wrote:
On Thu, 19 May 2005 07:19:13 +0000 (UTC), 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 suggesting eBay. I just had a look at a few machines on
there. The way in which the drum is supported on smaller rollers solves
the gearing problem rather neatly.

Chris


A local gentleman uses a 55 gallon drum with flanges welded inside to
provide a tumbling action, sprayed with bed liner for longevity. He
has it attached to the counterweight arms of a pumping unit here in
the oil fields. He can tumble a **** load of rocks at one time, for
little or no money G

Rather impressive how well it works.

Nice idea. Do you have any pictures of the contraption? I'd love to see.

Chris

Ill see if he has a run going this weekend and take some pictures.

He also makes spheres using home made Stuff.

Gunner

"Pax Americana is a philosophy. Hardly an empire.
Making sure other people play nice and dont kill each other (and us)
off in job lots is hardly empire building, particularly when you give
them self determination under "play nice" rules.

Think of it as having your older brother knock the **** out of you
for torturing the cat." Gunner

Christopher Tidy wrote:

So is there a consensus about how many RPM the barrel that holds the
stones (or in my case, old bolts from a project car) should be turning?


30 rpm was just my guess while I was thinking about a design this
morning. Having done a little more searching online I've found two
commercial models which run at 45 and 52 rpm, so this gives a rough
idea.


RPM must depend on size.

There is probably an ideal FPM range, just like metal removal.
Might depend on the type of rock, so variable speed might be desirable.

Christopher Tidy wrote:

Hi all,

When I was about 8 or 9 years old I really, really wanted a stone
polisher. I think they were rather expensive and also (probably
wisely) my parents thought that I would be bored having to wait months
for results, so I didn't get one for my birthday. Anyway, 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 reckon I probably need about a
30 rpm drum speed and 50 W of power for a small polisher. But the
drive needs to be sturdy and energy efficient if I'm going to leave it
running in the shed all year. A mulit-stage belt drive will be fiddly
and probably not very energy efficient. It seems to me that the best
solution would be an oil-filled worm and wheel gearbox, but I'm not
sure where to scrounge one from. Can anyone think of pieces of
industrial equipment which use a suitable gearbox, which I could look
out for in piles of junk etc? Has anyone built one of these before?
Any ideas would be welcome.

Best wishes,

Chris

Ok...from scratch and hopefully building on what other's have said:

1) round is better. The goal is a rolling motion with very little
actual sliding as the sliding causes flat spots. Rather than speed
itself being the most critical (other than running so fast that they
don't tumble), load is more important. For example, a drum 1/8 full may
not tumble at all (will slide) but the same speed and tub will tumble
perfectly when half full of rocks.

2) Start with the harbor freight cheepie..at 20 bucks for your first
try it's a cheap way to find out if you hate waiting it or not.

3) Part of tumbling is critically choosing the stones to charge the
machine with. You want a load that is all roughly the same hardness.
Also, youwant a mix of sizes from large to small rather than mostly
unifrom sizes. All large or all small will not polish well as surface
contact between the pieces is reduced.

4) Because you will be going through at least 4 grit sizes (5 for
some), clenliness is CRITICAL. If even one piece of coarse grit makes
it through to the finer stages you may have to start all over to get a
goood polish. The best solution is to have different drums for each
grit. Of course, you have to meticulously wash the stone load when
changing grits.

5) harbor freight does sell grit but you can probably get it cheaper in
greater bulk (5 pound containers) if you are really interested. When
you get to the polish stage, you'll also need plastic pellets to add to
the mix. These are readily available and really improve the polish time
and quality. Following the last polish, most rocks benefit from a run
of several days in a clean tumbler with a little borax added to the
water. Oh yea....in the coarser grits, gas can build up in the drum so
you either need to "burp" a closed drum or have provision for the gas to
come out by itself.

6) For the impatient, a vibratory tumbler is a LOT faster. If you are
actually going to invest more than a hundred bucks in the project, go
with a vibratory. One nice thing about vibratories is that you can
diamond saw shapes and the finished stones will maintain roughly the
same shape rather than having all the "points" rounded off as a rotary
tumbler does.

7) There's almost no money it...you have to do it all for the pleasure
of finding "treasures". The only money is in the really good stuff like
meteorites and hard rock digging that you need a saw to slab the good
stuff from. You can get lucky and find some worthwhile stuff here and
there but it usually takes more effort than just wandering arond picking
up rocks. Richardson Ranch in central Oregon is a wonderful (pay by
weight) place to go in an effort to find some "better" items. Free
camping, about a buck a pound, and to the best of my memory, 15000 acres
of ground with several locations of thunder eggs, agate, jasper, and
other goodies already located for you to do the digging yourself. The
prinevill. OR chamber of commerce also holds several mining claims for
agate beds in order to kep them open free to the public and encourage
tourism. Heck, basically anywhere you go there is something to be had.
Many books on "sites" are available (many sites are mostly played out
as it used to be a popular hobby.)

I hope this gets you started....it can be a real joy for the family to
go on treasure hunts for suitable rocks. Although kids tend to not
understand that granite, sandstone and some similar don't polish well
(you have to find a way to tell them it's pretty for them to keep but
not to polish), they still love the looking for pretties at the beach
and elsewhere. Almost anywhere you go you have something to keep busy
doing. Heck, I found some of the most beautiful jasper pieces as the
gravel topping of the truck parking by a hotel in Ontario, OR.

If you have more questions, let me know. I aint an expert but might be
able to help a bit.

Koz

Actually, tumblers of this gigantic size are often used in industry for
deburring and polishing stamped metal parts, but not for much else.

Rock tumblers and the ball mills that the pyros use for the production
of black powder are generally much smaller, typically not much large
than 6-8" or so in diameter.

The commonly used drive mechanism employs a belt driven shaft and and
an undriven shaft, both covered with rubber for friction, with the
milling/tumbling vessel resting on top.

Lloyd Sponenburgh, a frequent poster to this newsgroup, has published a
book on the subject so he is the person that I would turn to for
detailed advice.

Harry C.

Here's a link to a site that sells ball mills for amateur black powder
milling. The photos may give you some ideas:

http://www.hobbyfireworks.com/Balltext.html

Here is another from a web page describining a home-built rock polisher
or ball mill:

http://beachredmonds.com/pyro/mill.html

Enjoy!

Harry C.

"Tim Wescott" wrote in message
http://www.herbach.com

Great stuff. I haven't ordered from them in 15 years, but they were good
solid people the last time I dealt with them.

Tim Wescott

The Surplus Center is also a great place for "stuff".
http://www.surpluscenter.com/
Lane

Christopher Tidy writes:

When I was about 8 or 9 years old I really, really wanted a stone
polisher.

Build a Sponenmill:

http://www.wecreate4u.net/dwilliams/mill/mill.html

Any tips for using your basic tumbler to shine/clean/restore old nuts and
bolts? I've heard from vintage car restorers that they were great for
this... I'd guess to use a polish and not an abrasive though...

-Tim
"Koz" wrote in message
...


Christopher Tidy wrote:

Hi all,

When I was about 8 or 9 years old I really, really wanted a stone
polisher. I think they were rather expensive and also (probably
wisely) my parents thought that I would be bored having to wait months
for results, so I didn't get one for my birthday. Anyway, 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 reckon I probably need about a
30 rpm drum speed and 50 W of power for a small polisher. But the
drive needs to be sturdy and energy efficient if I'm going to leave it
running in the shed all year. A mulit-stage belt drive will be fiddly
and probably not very energy efficient. It seems to me that the best
solution would be an oil-filled worm and wheel gearbox, but I'm not
sure where to scrounge one from. Can anyone think of pieces of
industrial equipment which use a suitable gearbox, which I could look
out for in piles of junk etc? Has anyone built one of these before?
Any ideas would be welcome.

Best wishes,

Chris

Ok...from scratch and hopefully building on what other's have said:

1) round is better. The goal is a rolling motion with very little
actual sliding as the sliding causes flat spots. Rather than speed
itself being the most critical (other than running so fast that they
don't tumble), load is more important. For example, a drum 1/8 full may
not tumble at all (will slide) but the same speed and tub will tumble
perfectly when half full of rocks.

2) Start with the harbor freight cheepie..at 20 bucks for your first
try it's a cheap way to find out if you hate waiting it or not.

3) Part of tumbling is critically choosing the stones to charge the
machine with. You want a load that is all roughly the same hardness.
Also, youwant a mix of sizes from large to small rather than mostly
unifrom sizes. All large or all small will not polish well as surface
contact between the pieces is reduced.

4) Because you will be going through at least 4 grit sizes (5 for
some), clenliness is CRITICAL. If even one piece of coarse grit makes
it through to the finer stages you may have to start all over to get a
goood polish. The best solution is to have different drums for each
grit. Of course, you have to meticulously wash the stone load when
changing grits.

5) harbor freight does sell grit but you can probably get it cheaper in
greater bulk (5 pound containers) if you are really interested. When
you get to the polish stage, you'll also need plastic pellets to add to
the mix. These are readily available and really improve the polish time
and quality. Following the last polish, most rocks benefit from a run
of several days in a clean tumbler with a little borax added to the
water. Oh yea....in the coarser grits, gas can build up in the drum so
you either need to "burp" a closed drum or have provision for the gas to
come out by itself.

6) For the impatient, a vibratory tumbler is a LOT faster. If you are
actually going to invest more than a hundred bucks in the project, go
with a vibratory. One nice thing about vibratories is that you can
diamond saw shapes and the finished stones will maintain roughly the
same shape rather than having all the "points" rounded off as a rotary
tumbler does.

7) There's almost no money it...you have to do it all for the pleasure
of finding "treasures". The only money is in the really good stuff like
meteorites and hard rock digging that you need a saw to slab the good
stuff from. You can get lucky and find some worthwhile stuff here and
there but it usually takes more effort than just wandering arond picking
up rocks. Richardson Ranch in central Oregon is a wonderful (pay by
weight) place to go in an effort to find some "better" items. Free
camping, about a buck a pound, and to the best of my memory, 15000 acres
of ground with several locations of thunder eggs, agate, jasper, and
other goodies already located for you to do the digging yourself. The
prinevill. OR chamber of commerce also holds several mining claims for
agate beds in order to kep them open free to the public and encourage
tourism. Heck, basically anywhere you go there is something to be had.
Many books on "sites" are available (many sites are mostly played out
as it used to be a popular hobby.)

I hope this gets you started....it can be a real joy for the family to
go on treasure hunts for suitable rocks. Although kids tend to not
understand that granite, sandstone and some similar don't polish well
(you have to find a way to tell them it's pretty for them to keep but
not to polish), they still love the looking for pretties at the beach
and elsewhere. Almost anywhere you go you have something to keep busy
doing. Heck, I found some of the most beautiful jasper pieces as the
gravel topping of the truck parking by a hotel in Ontario, OR.

If you have more questions, let me know. I aint an expert but might be
able to help a bit.

Koz

Where do you get those ceramic pieces they use in vibratory tumblers?
That and some fluid - kerosene maybe? should do it.
- -
Rex Burkheimer
WM Automotive
Fort Worth TX

TheMan wrote:
Any tips for using your basic tumbler to shine/clean/restore old nuts and
bolts? I've heard from vintage car restorers that they were great for
this... I'd guess to use a polish and not an abrasive though...

-Tim
"Koz" wrote in message
...


Christopher Tidy wrote:


Hi all,

When I was about 8 or 9 years old I really, really wanted a stone
polisher. I think they were rather expensive and also (probably
wisely) my parents thought that I would be bored having to wait months
for results, so I didn't get one for my birthday. Anyway, 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 reckon I probably need about a
30 rpm drum speed and 50 W of power for a small polisher. But the
drive needs to be sturdy and energy efficient if I'm going to leave it
running in the shed all year. A mulit-stage belt drive will be fiddly
and probably not very energy efficient. It seems to me that the best
solution would be an oil-filled worm and wheel gearbox, but I'm not
sure where to scrounge one from. Can anyone think of pieces of
industrial equipment which use a suitable gearbox, which I could look
out for in piles of junk etc? Has anyone built one of these before?
Any ideas would be welcome.

Best wishes,

Chris


Ok...from scratch and hopefully building on what other's have said:

1) round is better. The goal is a rolling motion with very little
actual sliding as the sliding causes flat spots. Rather than speed
itself being the most critical (other than running so fast that they
don't tumble), load is more important. For example, a drum 1/8 full may
not tumble at all (will slide) but the same speed and tub will tumble
perfectly when half full of rocks.

2) Start with the harbor freight cheepie..at 20 bucks for your first
try it's a cheap way to find out if you hate waiting it or not.

3) Part of tumbling is critically choosing the stones to charge the
machine with. You want a load that is all roughly the same hardness.
Also, youwant a mix of sizes from large to small rather than mostly
unifrom sizes. All large or all small will not polish well as surface
contact between the pieces is reduced.

4) Because you will be going through at least 4 grit sizes (5 for
some), clenliness is CRITICAL. If even one piece of coarse grit makes
it through to the finer stages you may have to start all over to get a
goood polish. The best solution is to have different drums for each
grit. Of course, you have to meticulously wash the stone load when
changing grits.

5) harbor freight does sell grit but you can probably get it cheaper in
greater bulk (5 pound containers) if you are really interested. When
you get to the polish stage, you'll also need plastic pellets to add to
the mix. These are readily available and really improve the polish time
and quality. Following the last polish, most rocks benefit from a run
of several days in a clean tumbler with a little borax added to the
water. Oh yea....in the coarser grits, gas can build up in the drum so
you either need to "burp" a closed drum or have provision for the gas to
come out by itself.

6) For the impatient, a vibratory tumbler is a LOT faster. If you are
actually going to invest more than a hundred bucks in the project, go
with a vibratory. One nice thing about vibratories is that you can
diamond saw shapes and the finished stones will maintain roughly the
same shape rather than having all the "points" rounded off as a rotary
tumbler does.

7) There's almost no money it...you have to do it all for the pleasure
of finding "treasures". The only money is in the really good stuff like
meteorites and hard rock digging that you need a saw to slab the good
stuff from. You can get lucky and find some worthwhile stuff here and
there but it usually takes more effort than just wandering arond picking
up rocks. Richardson Ranch in central Oregon is a wonderful (pay by
weight) place to go in an effort to find some "better" items. Free
camping, about a buck a pound, and to the best of my memory, 15000 acres
of ground with several locations of thunder eggs, agate, jasper, and
other goodies already located for you to do the digging yourself. The
prinevill. OR chamber of commerce also holds several mining claims for
agate beds in order to kep them open free to the public and encourage
tourism. Heck, basically anywhere you go there is something to be had.
Many books on "sites" are available (many sites are mostly played out
as it used to be a popular hobby.)

I hope this gets you started....it can be a real joy for the family to
go on treasure hunts for suitable rocks. Although kids tend to not
understand that granite, sandstone and some similar don't polish well
(you have to find a way to tell them it's pretty for them to keep but
not to polish), they still love the looking for pretties at the beach
and elsewhere. Almost anywhere you go you have something to keep busy
doing. Heck, I found some of the most beautiful jasper pieces as the
gravel topping of the truck parking by a hotel in Ontario, OR.

If you have more questions, let me know. I aint an expert but might be
able to help a bit.

Koz

"Christopher Tidy" wrote in message
...
Hi all,

When I was about 8 or 9 years old I really, really wanted a stone
polisher. I think they were rather expensive and also (probably wisely) my
parents thought that I would be bored having to wait months for results,
so I didn't get one for my birthday. Anyway, 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 reckon I probably need about a 30 rpm drum speed
and 50 W of power for a small polisher. But the drive needs to be sturdy
and energy efficient if I'm going to leave it running in the shed all
year. A mulit-stage belt drive will be fiddly and probably not very energy
efficient. It seems to me that the best solution would be an oil-filled
worm and wheel gearbox, but I'm not sure where to scrounge one from. Can
anyone think of pieces of industrial equipment which use a suitable
gearbox, which I could look out for in piles of junk etc? Has anyone built
one of these before? Any ideas would be welcome.

Best wishes,

Chris

Here is a rather interesting rock polisher I ran across when I was looking
for info on a tumbler for some steel parts I cut.
http://www.acc.umu.se/~widmark/lwtrumld.html

Christopher Tidy wrote:

Hi all,

When I was about 8 or 9 years old I really, really wanted a stone
polisher. I think they were rather expensive and also (probably wisely)
my parents thought that I would be bored having to wait months for
results, so I didn't get one for my birthday. Anyway, 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 reckon I probably need about a
30 rpm drum speed and 50 W of power for a small polisher. But the drive
needs to be sturdy and energy efficient if I'm going to leave it running
in the shed all year. A mulit-stage belt drive will be fiddly and
probably not very energy efficient. It seems to me that the best
solution would be an oil-filled worm and wheel gearbox, but I'm not sure
where to scrounge one from. Can anyone think of pieces of industrial
equipment which use a suitable gearbox, which I could look out for in
piles of junk etc? Has anyone built one of these before? Any ideas would
be welcome.

Best wishes,

Chris

Make a thick rubber liner and you won't grind up your tub. Six sided is nice not a big bump.
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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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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There is one on the Net which uses a car tyre. 2 plywood plates fill
in the hole in the middle and it ran on a couple of bits of shafting.
IIRC the tyres lasted for years, despite being worn from the inside
out
Geoff

In article ,
Christopher Tidy wrote:

When I was about 8 or 9 years old I really, really wanted a stone
polisher. I think they were rather expensive and also (probably wisely)
my parents thought that I would be bored having to wait months for
results, so I didn't get one for my birthday. Anyway, 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.

Round & rubber is better than polygonal & steel. The setup at the local
serious rock shop back home was rather handy, if a bit large for a kid's
project - they had a set of tires on powered rollers - no fuss with
sealing the drum, and you could pull out a few to look at the progress
without it being the huge production it is with the small drums. Perhaps
for a smaller one you could scrounge a few lawn tractor tires - they
used car tires.

In article ,
geoff m wrote:

There is one on the Net which uses a car tyre. 2 plywood plates fill
in the hole in the middle and it ran on a couple of bits of shafting.
IIRC the tyres lasted for years, despite being worn from the inside

There is no need for anything in the hole with a car tire or tyre.
Simply keep the load size such that the fluid does not spew out the hole.

I built one years ago but it worked OK.

First I built a rectangle from Bed Frame angle iron. I mounted two
self aligning bearings at each of the short sides to hold 5/8 inch rod
parallel to the long sides. I made a couple of pulleys from some two
inch solid round bar and put one on each piece of 5/8 rod at one end.
I ran a heavy duty O ring (From some form of Caterpillar Dozer) on
those pulleys.

I mounted an old washing machine motor under the frame and welded legs
to the frame so the motor was not on the gound. The motor had a 3 inch
pulley and it drove an 8 inch? pulley attached to one of the 5/8
rods..

I used the commercial plastic barrels as they lasted forever and
weren't too expensive. The rectangular frame was long enough to run
three barrels at a time.

I only used self aligning bearings as a mate gave me them and the
housings. The 5/8 rod driving the barrels gave a really large amount
of downwards gearing.

Bob T (in Kojonup WA)

On Thu, 19 May 2005 09:16:33 -0500, Rex B wrote:

One standard 5- or 10-gallon propane tank, empty, flushed etc
Cut a square door in the side, hinge it, add a hasp or something to keep
it closed.
Line it with rubber sheet, held with good contact cement. The spray
bedliner might also work, you can get in in aerosol cans at any parts store.
Support it on a "Vee-block" of 4 inverted wheels - the stationary ones
that are used with casters.
2 additional angeled wheels at the ends keep it from moving axially.
Any small electric motor with a very small-diameter pulley on it.
Belt runs around the outside of the tank between the door and the top
(or bottom). Use a long thin flat serpentine belt. Might need a simple
spring tensioner.
Add rocks, carborundum power.
You'd probably want to tape the door after filling to make sure you
didn't leak carborundum all over the place.
- -
Rex Burkheimer
WM Automotive
Fort Worth TX

Christopher Tidy wrote:
Hi all,

When I was about 8 or 9 years old I really, really wanted a stone
polisher. I think they were rather expensive and also (probably wisely)
my parents thought that I would be bored having to wait months for
results, so I didn't get one for my birthday. Anyway, 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 reckon I probably need about a
30 rpm drum speed and 50 W of power for a small polisher. But the drive
needs to be sturdy and energy efficient if I'm going to leave it running
in the shed all year. A mulit-stage belt drive will be fiddly and
probably not very energy efficient. It seems to me that the best
solution would be an oil-filled worm and wheel gearbox, but I'm not sure
where to scrounge one from. Can anyone think of pieces of industrial
equipment which use a suitable gearbox, which I could look out for in
piles of junk etc? Has anyone built one of these before? Any ideas would
be welcome.

Best wishes,

Chris

There is a major distinction here. The "plasticky" tumblers are
available from toy stores as children's toys and most certainly are
trash. However, most any reputable gem and mineral store will carry
the professional grade tumblers. The most common brand is Loretone.
They come in different sizes and the price increases with size. I
would definitely buy the drum but making the motor housing would be a
good project. Another money saving tip: the good brands are nearly
indestructible, so a used one is a good buy. Also, the drums wear out
more frequently than the motors, so if you wanted to have one sure of
not leaking, I would try to find a used motor unit with a new drum.
Another thought when it comes to size: the silicon carbide abrasive is
expensive. My large tumbler, a 12 pounder, uses a pound of abrasive
per step and costs almost $30 per load to fill with the proper
material.
Hope this info is useful.

Thanks for all the useful information from different perspectives. I'm
starting to assemble some ideas about the kind of machine I might build
and the parts I'll need.

I think I have a suitable motor which I picked up from a skip when a
laboratory was being cleared last autumn. It's a shaded pole induction
motor rated at 30 W and it's really nicely built (they don't make them
like this anymore). It took me a while to work out the motor speed as I
sold my tachometer when I needed some cash. So I put a sticky label on
the shaft and held a pencil against it so it made a clicking noise. Then
I recorded the sound on the computer and looked at the waveform, and it
turns out the motor runs at 1425 rpm. I took a picture of the motor and
put it online:

http://www.mythic-beasts.com/~cdt22/...pole_motor.jpg

The most important question is how big a barrel I can turn with this
motor? I found one page showing a Thumler tumbler which had a 22 watt
motor, but it didn't list the barrel capacity. I was thinking of two 1.5
lb plastic barrels, which are 11.5 cm diameter, but they're actually
pretty small. The rubber 2.25 kg barrels (17 cm diameter) look nice but
they're expensive. I also have a 50 W at 950 rpm shaded pole induction
motor. It suffered a bit when the shed roof leaked, but it could
probably be restored. The 30 W motor has the advantage of being totally
enclosed so that no gunge can get inside, whereas the 50 W motor is
open. What do people think about power requirements?

I've found a 2.5 mm pitch toothed belt and aluminium pulleys for about
£12, which will provide the right reduction, and I can buy 15 mm round
stainless bar to make the rollers (about £4 for each roller). But the
bearings seem to be a problem. I really wanted to use those nice
self-aligning ball races in cast iron pillow blocks (probably with a 10
mm bore), but they cost a fortune - about £20 each! I could perhaps
afford £20 for all four. Any ideas where I might find surplus bearings
in the UK? I want the quality of my machine to be decent but I can't
afford to spend £80 on bearings. What do people think?

Once again, thanks for all the ideas.

Best wishes,

Chris

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 suggesting eBay. I just had a look at a few machines on
there. The way in which the drum is supported on smaller rollers solves
the gearing problem rather neatly.

Chris


A local gentleman uses a 55 gallon drum with flanges welded inside to
provide a tumbling action, sprayed with bed liner for longevity. He
has it attached to the counterweight arms of a pumping unit here in
the oil fields. He can tumble a **** load of rocks at one time, for
little or no money G

Rather impressive how well it works.

Nice idea. Do you have any pictures of the contraption? I'd love to see.

Chris


Ill see if he has a run going this weekend and take some pictures.

He also makes spheres using home made Stuff.

Thanks. Would be fascinating to see. What kind of spheres does he make?

Chris

"Christopher Tidy" wrote in message
...
Thanks for all the useful information from different perspectives. I'm
starting to assemble some ideas about the kind of machine I might build
and the parts I'll need.

I think I have a suitable motor which I picked up from a skip when a
laboratory was being cleared last autumn. It's a shaded pole induction
motor rated at 30 W and it's really nicely built (they don't make them
like this anymore). It took me a while to work out the motor speed as I
sold my tachometer when I needed some cash. So I put a sticky label on the
shaft and held a pencil against it so it made a clicking noise. Then I
recorded the sound on the computer and looked at the waveform, and it
turns out the motor runs at 1425 rpm. I took a picture of the motor and
put it online:

http://www.mythic-beasts.com/~cdt22/...pole_motor.jpg

The most important question is how big a barrel I can turn with this
motor? I found one page showing a Thumler tumbler which had a 22 watt
motor, but it didn't list the barrel capacity. I was thinking of two 1.5
lb plastic barrels, which are 11.5 cm diameter, but they're actually
pretty small. The rubber 2.25 kg barrels (17 cm diameter) look nice but
they're expensive. I also have a 50 W at 950 rpm shaded pole induction
motor. It suffered a bit when the shed roof leaked, but it could probably
be restored. The 30 W motor has the advantage of being totally enclosed so
that no gunge can get inside, whereas the 50 W motor is open. What do
people think about power requirements?

I've found a 2.5 mm pitch toothed belt and aluminium pulleys for about
£12, which will provide the right reduction, and I can buy 15 mm round
stainless bar to make the rollers (about £4 for each roller). But the
bearings seem to be a problem. I really wanted to use those nice
self-aligning ball races in cast iron pillow blocks (probably with a 10 mm
bore), but they cost a fortune - about £20 each! I could perhaps afford
£20 for all four. Any ideas where I might find surplus bearings in the UK?
I want the quality of my machine to be decent but I can't afford to spend
£80 on bearings. What do people think?

did you check ebay? i bought self aligning 1.5" pillow blocks for about $10
each.

Once again, thanks for all the ideas.

Best wishes,

Chris

Charles Spitzer wrote:
"Christopher Tidy" wrote in message
...

Thanks for all the useful information from different perspectives. I'm
starting to assemble some ideas about the kind of machine I might build
and the parts I'll need.

I think I have a suitable motor which I picked up from a skip when a
laboratory was being cleared last autumn. It's a shaded pole induction
motor rated at 30 W and it's really nicely built (they don't make them
like this anymore). It took me a while to work out the motor speed as I
sold my tachometer when I needed some cash. So I put a sticky label on the
shaft and held a pencil against it so it made a clicking noise. Then I
recorded the sound on the computer and looked at the waveform, and it
turns out the motor runs at 1425 rpm. I took a picture of the motor and
put it online:

http://www.mythic-beasts.com/~cdt22/...pole_motor.jpg

The most important question is how big a barrel I can turn with this
motor? I found one page showing a Thumler tumbler which had a 22 watt
motor, but it didn't list the barrel capacity. I was thinking of two 1.5
lb plastic barrels, which are 11.5 cm diameter, but they're actually
pretty small. The rubber 2.25 kg barrels (17 cm diameter) look nice but
they're expensive. I also have a 50 W at 950 rpm shaded pole induction
motor. It suffered a bit when the shed roof leaked, but it could probably
be restored. The 30 W motor has the advantage of being totally enclosed so
that no gunge can get inside, whereas the 50 W motor is open. What do
people think about power requirements?

I've found a 2.5 mm pitch toothed belt and aluminium pulleys for about
£12, which will provide the right reduction, and I can buy 15 mm round
stainless bar to make the rollers (about £4 for each roller). But the
bearings seem to be a problem. I really wanted to use those nice
self-aligning ball races in cast iron pillow blocks (probably with a 10 mm
bore), but they cost a fortune - about £20 each! I could perhaps afford
£20 for all four. Any ideas where I might find surplus bearings in the UK?
I want the quality of my machine to be decent but I can't afford to spend
£80 on bearings. What do people think?


did you check ebay? i bought self aligning 1.5" pillow blocks for about $10
each.

I did but I only checked eBay UK. Might be worth the postage from the US
if they're really cheap I guess. I'll take a look.

Thanks,

Chris

TheMan wrote:

Any tips for using your basic tumbler to shine/clean/restore old nuts and
bolts? I've heard from vintage car restorers that they were great for
this... I'd guess to use a polish and not an abrasive though...


Because the threads are so small don't they use the magnetically stirred
burnisher type machine in a liquid? Basically it's lots of little
stainless wires (needles) in a liquid and the magnet impinges them on
the parts to be deburred/cleaned (or vice versa depending on the
magnetic nature of the parts and media). From what I saw, you could do
it on a small scale with a standard lab magnetic stirer if the media
could be found.

Koz



-Tim
"Koz" wrote in message
...


Christopher Tidy wrote:



Hi all,

When I was about 8 or 9 years old I really, really wanted a stone
polisher. I think they were rather expensive and also (probably
wisely) my parents thought that I would be bored having to wait months
for results, so I didn't get one for my birthday. Anyway, 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 reckon I probably need about a
30 rpm drum speed and 50 W of power for a small polisher. But the
drive needs to be sturdy and energy efficient if I'm going to leave it
running in the shed all year. A mulit-stage belt drive will be fiddly
and probably not very energy efficient. It seems to me that the best
solution would be an oil-filled worm and wheel gearbox, but I'm not
sure where to scrounge one from. Can anyone think of pieces of
industrial equipment which use a suitable gearbox, which I could look
out for in piles of junk etc? Has anyone built one of these before?
Any ideas would be welcome.

Best wishes,

Chris



Ok...from scratch and hopefully building on what other's have said:

1) round is better. The goal is a rolling motion with very little
actual sliding as the sliding causes flat spots. Rather than speed
itself being the most critical (other than running so fast that they
don't tumble), load is more important. For example, a drum 1/8 full may
not tumble at all (will slide) but the same speed and tub will tumble
perfectly when half full of rocks.

2) Start with the harbor freight cheepie..at 20 bucks for your first
try it's a cheap way to find out if you hate waiting it or not.

3) Part of tumbling is critically choosing the stones to charge the
machine with. You want a load that is all roughly the same hardness.
Also, youwant a mix of sizes from large to small rather than mostly
unifrom sizes. All large or all small will not polish well as surface
contact between the pieces is reduced.

4) Because you will be going through at least 4 grit sizes (5 for
some), clenliness is CRITICAL. If even one piece of coarse grit makes
it through to the finer stages you may have to start all over to get a
goood polish. The best solution is to have different drums for each
grit. Of course, you have to meticulously wash the stone load when
changing grits.

5) harbor freight does sell grit but you can probably get it cheaper in
greater bulk (5 pound containers) if you are really interested. When
you get to the polish stage, you'll also need plastic pellets to add to
the mix. These are readily available and really improve the polish time
and quality. Following the last polish, most rocks benefit from a run
of several days in a clean tumbler with a little borax added to the
water. Oh yea....in the coarser grits, gas can build up in the drum so
you either need to "burp" a closed drum or have provision for the gas to
come out by itself.

6) For the impatient, a vibratory tumbler is a LOT faster. If you are
actually going to invest more than a hundred bucks in the project, go
with a vibratory. One nice thing about vibratories is that you can
diamond saw shapes and the finished stones will maintain roughly the
same shape rather than having all the "points" rounded off as a rotary
tumbler does.

7) There's almost no money it...you have to do it all for the pleasure
of finding "treasures". The only money is in the really good stuff like
meteorites and hard rock digging that you need a saw to slab the good
stuff from. You can get lucky and find some worthwhile stuff here and
there but it usually takes more effort than just wandering arond picking
up rocks. Richardson Ranch in central Oregon is a wonderful (pay by
weight) place to go in an effort to find some "better" items. Free
camping, about a buck a pound, and to the best of my memory, 15000 acres
of ground with several locations of thunder eggs, agate, jasper, and
other goodies already located for you to do the digging yourself. The
prinevill. OR chamber of commerce also holds several mining claims for
agate beds in order to kep them open free to the public and encourage
tourism. Heck, basically anywhere you go there is something to be had.
Many books on "sites" are available (many sites are mostly played out
as it used to be a popular hobby.)

I hope this gets you started....it can be a real joy for the family to
go on treasure hunts for suitable rocks. Although kids tend to not
understand that granite, sandstone and some similar don't polish well
(you have to find a way to tell them it's pretty for them to keep but
not to polish), they still love the looking for pretties at the beach
and elsewhere. Almost anywhere you go you have something to keep busy
doing. Heck, I found some of the most beautiful jasper pieces as the
gravel topping of the truck parking by a hotel in Ontario, OR.

If you have more questions, let me know. I aint an expert but might be
able to help a bit.

Koz

On Fri, 20 May 2005 16:26:31 +0000 (UTC), Christopher Tidy
wrote:

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 suggesting eBay. I just had a look at a few machines on
there. The way in which the drum is supported on smaller rollers solves
the gearing problem rather neatly.

Chris


A local gentleman uses a 55 gallon drum with flanges welded inside to
provide a tumbling action, sprayed with bed liner for longevity. He
has it attached to the counterweight arms of a pumping unit here in
the oil fields. He can tumble a **** load of rocks at one time, for
little or no money G

Rather impressive how well it works.

Nice idea. Do you have any pictures of the contraption? I'd love to see.

Chris


Ill see if he has a run going this weekend and take some pictures.

He also makes spheres using home made Stuff.

Thanks. Would be fascinating to see. What kind of spheres does he make?

Chris

He takes a chunk of rock, sorta kinda knocks the corners off with a
saw, and then turns them into highly polished spheres using a wierd
looking but really neat grinding arraingment of motorized cups and
grinding media.

Like these

http://www.therockshed.com/spheres.html

Gunner

"Pax Americana is a philosophy. Hardly an empire.
Making sure other people play nice and dont kill each other (and us)
off in job lots is hardly empire building, particularly when you give
them self determination under "play nice" rules.

Think of it as having your older brother knock the **** out of you
for torturing the cat." Gunner

Gunner wrote:
On Fri, 20 May 2005 16:26:31 +0000 (UTC), Christopher Tidy
wrote:


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 suggesting eBay. I just had a look at a few machines on
there. The way in which the drum is supported on smaller rollers solves
the gearing problem rather neatly.

Chris


A local gentleman uses a 55 gallon drum with flanges welded inside to
provide a tumbling action, sprayed with bed liner for longevity. He
has it attached to the counterweight arms of a pumping unit here in
the oil fields. He can tumble a **** load of rocks at one time, for
little or no money G

Rather impressive how well it works.

Nice idea. Do you have any pictures of the contraption? I'd love to see.

Chris


Ill see if he has a run going this weekend and take some pictures.

He also makes spheres using home made Stuff.

Thanks. Would be fascinating to see. What kind of spheres does he make?

Chris


He takes a chunk of rock, sorta kinda knocks the corners off with a
saw, and then turns them into highly polished spheres using a wierd
looking but really neat grinding arraingment of motorized cups and
grinding media.

Like these

http://www.therockshed.com/spheres.html

Very neat. Must have taken some ingenuity to build a machine that can
grind those.

Chris

"Ignoramus32374" wrote in message
...
On Fri, 20 May 2005 17:33:25 GMT, Gunner
wrote:
He takes a chunk of rock, sorta kinda knocks the corners off with a
saw, and then turns them into highly polished spheres using a wierd
looking but really neat grinding arraingment of motorized cups and
grinding media.

Like these

http://www.therockshed.com/spheres.html

That's most interesting. I would like to learn a bit more about that
process...

i

using one of these http://www.covington-engineering.com...e_machines.htm

regards,
charlie
http://glassartists.org/chaniarts

As an aside, we recently went camping about 25 miles NNW of Tonopah, Nevada.
We found an old mining operation where obsidian balls (called Apache tears
after polishing) were being taken out of a mountainside. There were
bazillions of them.

I often wondered how a large operation like that would process them. Or, if
they used them for something else besides tumbled stones for jewelry.

Any hints?

Steve