635 replies to this topic

[Pyrogeorge]

my charcoal is from grapevine..thats why is it so fast

[neo]

Hi!

I wonder if it's safe to use copper plated leadballs as milling media?
I've read on some pages that copper dont spark, and on other it says that it dose..

[Pyrogeorge]

Hi,
I make my new ball mill and i have a problem..
the jar is like to "stop and start" when i turn on the machine(with lead media inside 4kg).It does't make a full rotation continuously ..
what goes wrong??Here is the photos of my mill





I moved the wheels close to each other but it is the same..

Edited by pipipi, 11 December 2008 - 02:27 PM.

[paul]

Too slippery, not enough contact. Thats it. Really
Use another material (no garden hose) for your driver, sth more rubber-like.

Second: That plastics the jar is made of is even worse, regarding grip.
Wrap rubber-like duct tape or sth. around it.


Edit: And please, COVER that open motor

Edited by paul, 11 December 2008 - 03:55 PM.

[chris17]

Previous post summed it up pretty much! Look for rubbery fuel hose for the roller. As for the jar, you can buy a set of inner tubing for bicycle wheels. Cut the rubber tubing to strips and glue around the jar with epoxy for best durability

[spanner]

Hi,
I make my new ball mill and i have a problem..
the jar is like to "stop and start" when i turn on the machine(with lead media inside 4kg).It does't make a full rotation continuously ..
what goes wrong??

The jar looks like it's about 6" in diameter. If so, you want the roller to drive bar spacing to be 4-1/2", measured from the nearest distance from each other- O<-->O.

Taken another way, the angle between the c/l of the jar and both the drive and driven rollers should be 60 degrees. Your mill looks to have more spacing than that.

The drive bar should be "lifting" the jar- so the motor should be rotating counterclockwise, as viewed from the pulley end. This may well be the major problem, as many motors rotate CW rather than CCW.

If there's still slippage, try covering the drive bar with a tight-fitting piece of rubber hose (automotive heater hose is often used), or wrap the jar with "friction tape" (as opposed to, say, electrical tape- which is slippery). Some swear by duct tape.

If the jar's capacity is a gallon, you are undercharged, media-wise. If using lead media, it takes about 30 pounds to fill a 1 gallon jar properly. But whatever the capacity of the jar, the media should occupy 1/2 the jar's volume, the material being processed should be equal to about 1/4 of the jar's volume, i.e. the material should fill all the space between the media PLUS one media diameter more.

Lastly, check the RPM of the jar. A 6” jar with ½" media should run about 73 RPM, 1” media is about 77 RPM.
A 5" diameter jar with 1/2" media is 81 RPM.

EDIT- Sorry for the non-metric measurements.

Edited by spanner, 11 December 2008 - 04:18 PM.

[cooperman435]

it will also help if your powered roller drives the bottom of the jar towards the ideler rollers as this will increase grip whereas if it drives away it will help it slip.

I dont know which way it drives now so you may already have that direction in your set up.

Nice jar btw :-) Ballmill looks good too!

[digger]

And to state the obvious 2 driven rollers are better than 1.

[Pyrogeorge]

thanks for your replies.
i will make some modifications and i will inform you again

[Pyrogeorge]

i glue inner tube on the roller and now is better but the jar do some "shakes"
maybe i will put inner tube to the jar too..

[Pyrogeorge]

Too slippery, not enough contact. Thats it. Really
Use another material (no garden hose) for your driver, sth more rubber-like.

Second: That plastics the jar is made of is even worse, regarding grip.
Wrap rubber-like duct tape or sth. around it.


Edit: And please, COVER that open motor

why to cover the moter?maybe will heat more if it covered

[digger]

why to cover the moter?maybe will heat more if it covered

The answer to this is to protect the motor from any explosive dusts that could be ignited by the motor.

This is however open to debate. If you have the mill in a safe area where no powders are mixed or used and the mill jar is opened and closed in a different area then there are only the risks of the jar splitting or the lid screwing off to consider. These risks can obviously be mitigated by jar design and regular checks on the condition of your jar.

[paul]

why to cover the moter?maybe will heat more if it covered

Because you aren´t always aware of what your motor does, eh? There is ALWAYS the risk of
sparks or parts of the motor running hot.

Just seperate your two parts, motor and milling cabinet. Always use the safest possible way.

Sorry, this is in NO way meant arrogant but I would never have asked the why-seperate-the-both-question!
It is YOUR safety there. You´re not playing with 10g of lightly con tained black powder. That jar looks
like you´re gonna make a lot more at once.

So, take that tip and add at least one layer of thick wood between motor and jar, so no powder can directly fall onto/into
the motor.
Mo overheating issues then! I´m using the same design on my mill.

[Pyrogeorge]

ok,i will put a wood between motor and jar.

thanks!

[Arthur Brown]

It's easy not to spill anything when the drum is empty! When the drum is full and has 12 hours to run it's almost impossible to go long without a dust of something showing.

If and when the mill jar wears out and the contents spill on the motor.......