Vince Pitelka on mon 10 nov 03
Taylor -
This sounds like the standard old Amaco ballmill that is so common in
schools. But they are great machines when in proper order. I have rebuilt
several of them.
To fix the rollers, you need to strip them completely of all residual
rubber. Then you need to take one of the bare shafts to a good auto supply
store (not CarQuest, AutoZone or any of those other crappy superstores -
BOYCOTT THEM!! - go to a good Napa store or a local place), and get some
fiber-reinforced rubber heater hose that will be a snug fit over the shafts.
Get the best quality stuff they have. Cut the hose to length. Mix a good
two part epoxy and coat the shaft, and poke some inside the end of the hose,
and then slide the hose on over the shaft. Normally we would use rubber
cement or contact cement to attach rubber to metal, but those adhesives need
to get tacky (partially dry) before the surfaces are joined, and you would
not be able to slide the rubber on over the shaft. If you slide it on when
the contact cement is still wet, it will not dry properly, because it needs
air to cure. Two-part epoxy will cure without air.
I don't know if you can replace those little hinge-top oil cups, but you can
simply apply oil, and then close them off with a little wad of rubber or
cork.
The ball mill speed does not change with different jar sizes. Same speed
for all. I don't think it matters at all whether you use the same kind of
grinding media or a mixture of sizes and shapes. And be sure you do not
overfill the jars. For good grinding, they should never be filled more than
halfway. For this kind of ballmill, you also need to be grinding a
water-suspension slurry. Fill the jar 1/3 with grinding media, then add
your shale slurry (50-50 ground shale and water) until the jar is half full.
With all the air spaces between the grinding media, the jar will actually be
more than 1/4 full of slurry.
Good luck -
- Vince
Vince Pitelka
Appalachian Center for Craft
Tennessee Technological University
1560 Craft Center Drive, Smithville TN 37166
Home - vpitelka@dtccom.net
615/597-5376
Office - wpitelka@tntech.edu
615/597-6801 x111, FAX 615/597-6803
http://iweb.tntech.edu/wpitelka/
http://www.tntech.edu/craftcenter/
David Hendley on mon 10 nov 03
Taylor, how much is the tuition at Baylor U.?
And they can't afford a working ball mill?
First of all, you are correct - it seems like the same set-up cannot
possibly work for both quart and gallon jars. One or the other, or
possibly both, will not be turning at the proper critical speed, and
no grinding will get done.
As for the grease cups - that is no big deal. These are not bearings,
they are bushings - common in slow speed, low torque applications,
such as ball mill rollers.
Just force more grease into the cups. You can still use a grease
gun - just hold it with your hand and get as much grease in as you
can.
Off the top, I think the easiest way to give the rollers some traction
would be your "rubber bands around the jars" idea, but use
industrial strength rubber bands. Maybe mold bands, that are
used in slip casting operations, maybe inner tube bands.
I got both round and cylindrical porcelain balls when I got my
ball mill. I was told that the spheres were for wet grinding and
the cylinders were for dry grinding. That is how I have done it
all these years, but I can't say for sure why, or if that is
standard practice.
Happy ball milling,
David Hendley
david@farmpots.com
http://www.farmpots.com
----- Original Message -----
Today wasn't a very fun day at school. I spend all my time
trying to ball mill some shale I collected from some local
road construction. I already crushed it with mortar and
pestle so it would pass a very rough kitchen sieve and I
was hoping to use the school's ball mill to render it super
fine, like me!
Here is what I have discovered about the school's ball mill.
We have what looks like gallon jars and quart jars. They are
nice porc jars with good porc lids. Well the quart doesn't,
but I just used a plastic yogurt container and some bailing
wire and that was that. The problem with the mill is the
rollers. Both of them are covered in deteriorating rubber.
It is now hard and slick, so the jars fail to rotate. The
bearings are also in need of some attention. Their nipples
at one time had little lids that closed them off to dust and
what not--not like the grease gun nipples that I am familiar
with. Baby greese cups? I think I can replace those no
problem.
Fredrick Paget on mon 10 nov 03
Besides the other fixes already proposed check the bearings. the
idler roll should spin freely. Sounds like it is dragging and causing
the slippage.
Fred
--
From Fred Paget, Marin County, California, USA
fredrick@well.com
Hendrix, Taylor J. on mon 10 nov 03
Howdy y'all:
Today wasn't a very fun day at school. I spend all my time=20
trying to ball mill some shale I collected from some local=20
road construction. I already crushed it with mortar and=20
pestle so it would pass a very rough kitchen sieve and I=20
was hoping to use the school's ball mill to render it super=20
fine, like me!
Here is what I have discovered about the school's ball mill. =20
We have what looks like gallon jars and quart jars. They are=20
nice porc jars with good porc lids. Well the quart doesn't,=20
but I just used a plastic yogurt container and some bailing=20
wire and that was that. The problem with the mill is the=20
rollers. Both of them are covered in deteriorating rubber. =20
It is now hard and slick, so the jars fail to rotate. The=20
bearings are also in need of some attention. Their nipples=20
at one time had little lids that closed them off to dust and=20
what not--not like the grease gun nipples that I am familiar=20
with. Baby greese cups? I think I can replace those no=20
problem.
I tried using first the gallon jar to mill my entire batch of=20
shale, but as soon as the rollers heated up, the jar began=20
slipping. Little if any milling was being done at that point. =20
I then tried the much lighter quart jar, but it too began to=20
slip quickly. Roughing up the surface of the rollers didn't=20
help and probably just made the covering worse. Putting rubber=20
bands around the jar to improve traction might have worked if=20
they could have held up to all that friction. They snapped=20
shortly after I turned on the mill.
Does anyone have any suggestions for how to refurbish the=20
rollers? Tool dip? I want to pull the maintenance on this=20
machine just for the experience. I don't think anything will=20
get done in the near future otherwise. Because I am itching=20
to try this local material in some glaze testing, the ceramic
studio is going to get some free repair.
Now I have some general questions. The grinding media is porc=20
balls. Some of the balls are spherical and some are cylindrical. =20
Is it important to have a mixture? Should one only charge a jar=20
with the same shape media? Also, unless the switch was hiding
somewhere, I don't know how the mill changes speed for the=20
various size jars. Won't the critical speed change from the=20
gallon jar to the quart jar? Are we counting on slippage of=20
the jars to regulate milling speed? Gosh my head hurts.
So what up with that?
Taylor, in Waco
Earl Brunner on mon 10 nov 03
Not for grease Taylor, for oil, that's what you put in the fittings with
the little lids.
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG] On Behalf Of Hendrix,
Taylor J.
Sent: Monday, November 10, 2003 4:15 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Ball mill repair etc.
Howdy y'all:
Their nipples
at one time had little lids that closed them off to dust and
what not--not like the grease gun nipples that I am familiar
with. Baby greese cups? I think I can replace those no
problem.
wayneinkeywest on mon 10 nov 03
Taylor:
Maybe a stupid question, as I've never seen a ball mill.
Could one use some of that closed cell foam
pipe insulation from (gasp!) Home Despot, and rubber band those to the
rollers instead of trying to alter the jars?
Wayne Seidl
80 this am, 70 this pm, and blowing 25 knots
from the south. Wind chimes are going nuts
and all the birds are grounded.
----- Original Message -----
From: "Hendrix, Taylor J."
To:
Sent: Monday, November 10, 2003 7:14 PM
Subject: Ball mill repair etc.
Howdy y'all:
Today wasn't a very fun day at school. I spend all my time
trying to ball mill some shale I collected from some local
road construction. I already crushed it with mortar and
pestle so it would pass a very rough kitchen sieve and I
was hoping to use the school's ball mill to render it super
fine, like me!
Here is what I have discovered about the school's ball mill.
We have what looks like gallon jars and quart jars. They are
nice porc jars with good porc lids. Well the quart doesn't,
but I just used a plastic yogurt container and some bailing
wire and that was that. The problem with the mill is the
rollers. Both of them are covered in deteriorating rubber.
It is now hard and slick, so the jars fail to rotate. The
bearings are also in need of some attention. Their nipples
at one time had little lids that closed them off to dust and
what not--not like the grease gun nipples that I am familiar
with. Baby greese cups? I think I can replace those no
problem.
I tried using first the gallon jar to mill my entire batch of
shale, but as soon as the rollers heated up, the jar began
slipping. Little if any milling was being done at that point.
I then tried the much lighter quart jar, but it too began to
slip quickly. Roughing up the surface of the rollers didn't
help and probably just made the covering worse. Putting rubber
bands around the jar to improve traction might have worked if
they could have held up to all that friction. They snapped
shortly after I turned on the mill.
Does anyone have any suggestions for how to refurbish the
rollers? Tool dip? I want to pull the maintenance on this
machine just for the experience. I don't think anything will
get done in the near future otherwise. Because I am itching
to try this local material in some glaze testing, the ceramic
studio is going to get some free repair.
Now I have some general questions. The grinding media is porc
balls. Some of the balls are spherical and some are cylindrical.
Is it important to have a mixture? Should one only charge a jar
with the same shape media? Also, unless the switch was hiding
somewhere, I don't know how the mill changes speed for the
various size jars. Won't the critical speed change from the
gallon jar to the quart jar? Are we counting on slippage of
the jars to regulate milling speed? Gosh my head hurts.
So what up with that?
Taylor, in Waco
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Jan L. Peterson on mon 10 nov 03
Some of our old mills at the mines used balls. The garnet mine down In St.
Maries still does, I think. I would get hold of an old ball mill hand and ask
him about those things. He's know. Or a mining supply store. They would.
Me, I would thing that the rollers would have to be taken off, and new rubber
sleeves would have to be put on. Individually. Rollers all re-aligned. What
the different shapes are for, or whether they'd make a difference in speed, if
the mill has more than one speed, I don't know. I saw the one at the garnet
mill working, but failed to ask about it. Jan, the Alleycat
Hank Murrow on mon 10 nov 03
On Nov 10, 2003, at 4:14 PM, Hendrix, Taylor J. wrote:
> Here is what I have discovered about the school's ball mill.
> The problem with the mill is the rollers. Both of them are covered
> in deteriorating rubber. It is now hard and slick, so the jars fail
> to rotate. Does anyone have any suggestions for how to refurbish the
> rollers?
Dear Taylor;
Your dept. has a gem in you. What I recommend is going to an industrial
hose supply store with your rollers in hand. They will probably be able
to outfit you with lengths of rubber hose that will barely (with soap)
slide onto the shafts to provide a new surface. I found heavy duty hose
that fit my 7/8" shafts perfectly, and it has held up well.
> Now I have some general questions. The grinding media is porc
> balls. Some of the balls are spherical and some are cylindrical.
> Is it important to have a mixture? Should one only charge a jar
> with the same shape media? Also, unless the switch was hiding
> somewhere, I don't know how the mill changes speed for the
> various size jars. Won't the critical speed change from the
> gallon jar to the quart jar? Are we counting on slippage of
> the jars to regulate milling speed?
The cylindrical media grinds faster, that's all. Good to have a mix of
sizes.....1/2" and 3/4" for example. 1" for larger jars (3 gallon +).
Look up the formula for critical speed as well as application
suggestions in Cardews book in the appendices. It is 54.19/ square
root of the internal radius in feet. You may need to build a controller
for the motor.
> Gosh my head hurts.
Take some time to work on it, head will get better.
Cheers, Hank
www.murrow.biz/hank
Richard Aerni on mon 10 nov 03
On Mon, 10 Nov 2003 18:14:35 -0600, Hendrix, Taylor J.
wrote:
The problem with the mill is the
>rollers. Both of them are covered in deteriorating rubber.
>It is now hard and slick, so the jars fail to rotate. >
>
Roughing up the surface of the rollers didn't
>help and probably just made the covering worse. Putting rubber
>bands around the jar to improve traction might have worked if
>they could have held up to all that friction. They snapped
>shortly after I turned on the mill.
>
>Does anyone have any suggestions for how to refurbish the
>rollers?
Taylor,
I'll tell you what I did for my ball mill, and it worked fine. It's a Red
Green type answer...duct tape...
I just took duct tape and put on two bands about 1/4 inch thick on each
roller. I've got heavy steel rollers without any rubberized coating, just
the duct tape. Works fine.
Before you give an expensive and complicated fix a try, get yourself a roll
of duct tape.
Best,
Richard Aerni...half of Bloomfield, half of the new studio, NY
Cat Yassin on tue 11 nov 03
In a message dated 11/10/2003 6:38:12 PM Central Standard Time,
Taylor_Hendrix@BAYLOR.EDU writes:
> Now I have some general questions. The grinding media is porc
> balls. Some of the balls are spherical and some are cylindrical.
> Is it important to have a mixture?
Taylor, I'm no expert... but I would think a variety of sizes would make for
a faster and finer grinding. Imagine only having 3/4 " balls (talking ball
mill balls here) and if you laid them out on a table touching each other there
would be large gaps between each one. (Ok, stop snickering) If you took a
variety of sizes they would "fit" better against each other, the smaller ones
filling in the gaps and thus more surface would be grinding your shale at any given
time.
-Cat Yassin
San Antonio, Tx
Yeehaw.
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