George G wrote:
A while ago there was some interest in building a sphere machine. I
made one with two motors that I had from old office equipment. You
almost have to build one around the motors you can get a hold off. The
cups are pipe reducers according to the size of the sphere you are
grinding. One third smaller. I mounted it on an old aluminum griddle.
I have made spheres up to 3" diameter of petrified wood, granite, agate
and obsidian. The main thing is to rough it down with a carborundum
wheel to a sphere as close as possible. Then use grits the same as
tumbling stones. After roughing your rock to a sphere, in 2 or 3 hours
you can have an obsidian sphere. I have made them as close as .001
diameter.
George

That is really neat. How do you supply the abrasive to the cups? Do you
ever find that a sphere gets stuck, so that it is only ground where it
touches the cups?

I might be tempted to build one of these myself.

Thanks for the picture!

Chris

George G wrote:
A while ago there was some interest in building a sphere machine. I
made one with two motors that I had from old office equipment. You
almost have to build one around the motors you can get a hold off. The
cups are pipe reducers according to the size of the sphere you are
grinding. One third smaller. I mounted it on an old aluminum griddle.
I have made spheres up to 3" diameter of petrified wood, granite, agate
and obsidian. The main thing is to rough it down with a carborundum
wheel to a sphere as close as possible. Then use grits the same as
tumbling stones. After roughing your rock to a sphere, in 2 or 3 hours
you can have an obsidian sphere. I have made them as close as .001
diameter.
George

That's really neat. How do you apply the abrasive? Do the spheres ever
get stuck so that they're only polished on two sides?

I'm tempted to build one of these sometime...

Thanks for the picture!

Chris

Christopher Tidy wrote:

George G wrote:

A while ago there was some interest in building a sphere machine. I
made one with two motors that I had from old office equipment. You
almost have to build one around the motors you can get a hold off. The
cups are pipe reducers according to the size of the sphere you are
grinding. One third smaller. I mounted it on an old aluminum griddle.
I have made spheres up to 3" diameter of petrified wood, granite, agate
and obsidian. The main thing is to rough it down with a carborundum
wheel to a sphere as close as possible. Then use grits the same as
tumbling stones. After roughing your rock to a sphere, in 2 or 3 hours
you can have an obsidian sphere. I have made them as close as .001
diameter.
George


That is really neat. How do you supply the abrasive to the cups? Do you
ever find that a sphere gets stuck, so that it is only ground where it
touches the cups?

I might be tempted to build one of these myself.

Thanks for the picture!

Chris

That looks easy - Used on in school. The grit is added on the outside as it
works on the outside lip and stone, not inside like most think. The inside
is hollow - as the center almost doesn't turn while the outer distances do...

It looks like a chunk of Onyx being made into a sphere. I did Obsidian (glass)(volcano)
and Lepadite (sp) - but it didn't work well. I mostly cut Sapphire in those days.
Some other exotic materials also.

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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"George G" wrote in message
...

- Two things:
1. Don't post attachments to non-binaries groups.
2. Your attachment isn't even coming through right anyway
("snapshot-filename"??).

Hm, WebTV, that explains it...

Tim

--
"California is the breakfast state: fruits, nuts and flakes."
Website: http://webpages.charter.net/dawill/tmoranwms

You devise a method to slowly drip water and grit. IV bag can drip your
water, and use a clock motor with a twisted piece of flat attached to it
that ends up being fluted. This passes horizontally through a small can or
plastic bottle full of grit. As it protudes out, when turning, it delivers a
small charge of grit to the sphere below.


"Christopher Tidy" wrote in message
...
George G wrote:
A while ago there was some interest in building a sphere machine. I
made one with two motors that I had from old office equipment. You
almost have to build one around the motors you can get a hold off. The
cups are pipe reducers according to the size of the sphere you are
grinding. One third smaller. I mounted it on an old aluminum griddle.
I have made spheres up to 3" diameter of petrified wood, granite, agate
and obsidian. The main thing is to rough it down with a carborundum
wheel to a sphere as close as possible. Then use grits the same as
tumbling stones. After roughing your rock to a sphere, in 2 or 3 hours
you can have an obsidian sphere. I have made them as close as .001
diameter.
George

That is really neat. How do you supply the abrasive to the cups? Do you
ever find that a sphere gets stuck, so that it is only ground where it
touches the cups?

I might be tempted to build one of these myself.

Thanks for the picture!

Chris