140 replies to this topic

[damasta105]

Hi all,
I think this applies to chemistry as it is a process needed for the chemicals of BP...
But why are all ball mills designed the same way? They all work on the principle of a barrel rotating on rollers, why are no ball mills (that I have seen) designed to have the barrel rotating on an axis with a motor at the end, wouldnt this require a much smaller motor and obtain more efficiency as there would be negligeble power lost by friction to the rollers.
Would there be any problem with an axis running right through the mixing barrel?
If there is I suppose it could have 2 bolts out of each end (brass bolts of course!) so there is no axis in the barrel itself.
I was just wondering as it would significantly decrease the cost of such a machine and be more efficient? But I also posted as to ask about any flaws in the design, surely if it was good it would be used often in ball mill designs.

Rory.

[Chaz]

Its because most motors run at way too high RPM to attach the jar directly to the motor. My motor runs at 1800rpm, which is obviously way too much. You have to get a special geared motor to attach the jar directly to the axle.

I use a pulley systemfor my mill, to bring the RPM down to about 130.

My Ball Mill Page.

[Stuart]

Windscreen whipper motors run at the right speed to turn a barrel hooked straight up to the motor. I already use this design and consider it superior to the normal design on rollers as its considerably easier to assemble as there are no fancy parts like pulleys, bearings etc

My Ball Mill Page

The pictures are currently off but they will be on in a few days when my bandwidth is reset then you can see the read thing

Stuart

[paul]

http://deutsch.250x....kumue/kumue.htm

Thats my mill. Because my milling jar isn?t that big in diameter i can only make 100g blackpowder at once...

But thats not the problem

[BigG]

Its because most motors run at way too high RPM to attach the jar directly to the motor. My motor runs at 1800rpm, which is obviously way too much. You have to get a special geared motor to attach the jar directly to the axle.

I use a pulley systemfor my mill, to bring the RPM down to about 130.

My Ball Mill Page.

Chez, there are many motors that run at 60RPM. This would not stand for a reason to abundant the design.

There are many other points that can be raised against it.

1) How do you load such a jar comfortably? Afterall, it will have a rod going through it making things very starnge.
2) How do you protect from leakage?
3) Size ? having a jar rotating in the middle of the exile means your constraction need to be high enough to allow the jar to rotate freeley.
4) Multi Jars ? how do you allow more then one jar to be used together?


Overall, I consider the traditional design very simple and I don?t see the removal of an axial such a necessity. Designing the support for the jar with a single rod going through it seem more complicated to me.

[Stuart]

Don't need a rod through the middle. If you just have a nut and bolt on the lid and a nut and bolt on the back of the mill that does the same job.

1. Loading and uploading is simple. On my ball mill, there are threads on the bit that sticks out of the motor. I fix the bolt that is in the lid to this with a nut so uploading just means undoing the nut

2. Use an airtight container

3. Big wooden frame

4. You can use more than one jar but you can use big jars because unlike he traditional design, the bigger the jar, the faster it turns so a slow motor can be used

I will have a picture of my ball mill up in a few days so you can all see it then

Edited by Stuart, 28 April 2004 - 03:44 PM.

[willd]

and of course use aluminium or brass bolts.

[BigG]

Don't need a rod through the middle. If you just have a nut and bolt on the lid and a nut and bolt on the back of the mill that does the same job.

1. Loading and uploading is simple. On my ball mill, there are threads on the bit that sticks out of the motor. I fix the bolt that is in the lid to this with a nut so uploading just means undoing the nut

2. Use an airtight container

3. Big wooden frame

4. You can use more than one jar but you can use big jars because unlike he traditional design, the bigger the jar, the faster it turns so a slow motor can be used

I will have a picture of my ball mill up in a few days so you can all see it then

okay then Good luck. Let us know how it is coming along...

P.S. The bigger the jar the faster it turns??? I thought that with the design suggested will cuase the same RPM regardless of the jar size...

[Creepin_pyro]

I finally attempted making a ball mill last night. It consists of a 500g capacity cylindrical tub, sitting in a cardboard box, on two 5/8" dowels (fixed). An ice cream machine motor is attached to the outside of the box, which is attached to the centre of the tub lid through the box wall. No spinning dowels in sight. I've let it run all night with a load of charcoal, and it was happily tumbling away this morning - no hot spots or leakage. No time to check the results before work , so we'll see. I'm a little concerned about the size of my balls - I think they are about 30mm - should be smaller, right?

[damasta105]

well im glad that some people use this design, although i dont think that the design is more complicated, in fact i think it simplifies things!
There is also an amazing tool I have found to seal things up nice and good- silicone sealant
for the building of a support for the axis, an extremely simple X shaped bits of wood would suffice, of course there is the problem with motor RPM, that could easily be fixed with pulleys although I do agree that if you have a high RPM motor or plan on using more than 1 mill it would be easier to have a traditional design would be better, although for cheaper mills with smaller motors i think this design would be cheaper and easier to make?

Thanks for all the help.

[willd]

I think stuart means the outside of the jar turns faster.

[Charged]

What the tube should be made where the BP or other stuff goes in.What are suitable crushing balls or bolts to be put in to the ball mill.

[Creepin_pyro]

What the tube should be made where the BP or other stuff goes in.

I'm assuming you want to know what kind of materials can be used for milling jars, yes? I would stand back and think about what you're doing a little more carefully. I'd think about what you're going to put in the container, as this is what will kill you if you get it wrong.

Bad milling jar = possibility of a leak
Bad milling media/chemicals = possibility of flying pieces of death going everywhere

As for using bolts, that's a very BAD idea. Ferrous/chrome plated balls are OK for use with single chemicals, but if you want to mill anything mixed, you will need lead or antimony/lead media. I would not even consider milling anything except single chemicals without a professional ball mill containing the appropriate media.

[Rhodri]

Good reply!

[bmiller14]

I am soon going to try a chicken spit moter my mom got so she could cook whole chicken on the BBQ, I am hoping she wont notice.