Paul Herman on thu 5 nov 09
Hank, Doug and Lee,
I don't know if any of you have ever used an impact mill, but I sure
like mine a lot. It makes a jaw crusher look like a slow moving
glacier by comparison. For crushing granodiorite, feldspar and other
medium-hard stuff it's very fast. The feed material has to be broken
down to about 1 inch and smaller. There is a four vaned paddlewheel in
a steel canister that spins at 2,000 rpm and batters the stuff down to
about 10- mesh, then blows it into the collector. Most of it is much
finer. I sift it to 16- and put that material in the pebble mill. The
impact mill is like a hammer mill, but without the swinging hammers. I
bought it for a hundred bucks (sans motor) from a guy who came in the
driveway one day because he thought I might need it.
I started out with a small electric powered jaw crusher that a friend
built for me. He's a guy who likes the challenge of this kind of
stuff. I didn't have $500 for the really good bearings, so it has worn
out bearings and is awaiting repair in my shop. I imagine they might
be $800 by now. It was a slow proposition to crush stuff in it.
I also bought one of the "mini mills" that Lee is writing about. It's
a great little hand powered jaw crusher for making samples and small
runs of a pound or two, but more than that can get tiresome. One jaw
is stationary and one moves up and down in a slight curve.
It's always nice to find material that Mother Nature has milled for us.
Good milling,
Paul Herman
Great Basin Pottery
Doyle, California US
www.greatbasinpottery.com/
On Nov 5, 2009, at 3:57 PM, Hank Murrow wrote:
> On Nov 5, 2009, at 1:33 PM, douglas fur wrote:
>
>> Lee
>> OK,so when I imagine "two steel plates that are set closer at the
>> bottom than the top." I get the picture that they make a narrow
>> "vee",
>> touching at the bottom. I imagine then, that one wheel is passive
>> (rotates
>> freely) and the other is driven so that the material gets rolled
>> between the
>> plates and consequently the material transmits some of the rotation
>> to the
>> passive disc.
>> Sounds like a nice idea but does it match reality?
>
> Well, Duff;
>
> Hank, not Lee here........
> It certainly does. My jaw crusher and plate mill will take hardball-
> sized rocks(the harder the better) down to 18_10 mesh in the jaws and
> the plate section will take that down to -100 mesh. The ball mill is
> used to go finer. it does take a five horse B&S motor to do the work
> but it is fast...... can process feldspar at 1000#s a day.
>
> Cheers, Hank in Eugene
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