Poor Mans Ball Mill





Introduction: Poor Mans Ball Mill

About: One day I shall own a Delorean.

Make a cheap ball mill for light use.

I needed to grind up some cat little to test if it would be suitable as a source of bentonite clay, I needed a ball mill but I didn't want to spend a lot of time making a decent ball mill if the cat litter wouldn't suit my needs.

Step 1: What You Will Need

you will need the following


a plastic tub ideally with a screw top

a cordless drill

1 bolt

1 nut or wing nut

2 washers

and some lead balls, you can make these using the following instructable


Step 2: Prepare the Tub

Drill a hole in the top of the tub the same size of the bolt

put a washer on the bolt and push it through the lid so the shaft of the bolt is on the outside.

then put a washer on the bolt and put the nut on the bolt and tighten it up.

that's it, for the tub, just pour in the medium you wish to grind and put in the lead balls, screw the top on and move to the next step of this instructable.

Step 3: Prepare the Drill

preparing the drill is really easy

clamp the drill to a solid desk

put the bolt on the tub in to the chuck of the drill and lock it in place.

Step 4: Start the Milling

ok we are now ready to start milling.

using another clamp, a pump clamp would be ideal, tighten it around the grip of the drill depressing the button, do this slowly you don't want the drill to get out of control.

its best with this method of milling to go slowly, other ball mills run faster than this one, but this is not intended to be used a lot, it's a light mill.

have a look at it working.

after about an hour and a half it has turned the cat litter in to a fair powder, if it left it much longer it could be much finer.



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    9 Discussions

    In Australia, you can get bentonite at most farm supply places. It is apparently used as a stock feed supplement. It comes in a bag, and is granulated, so it still needs to be broken up. 1 bag lasts for a VERY long time. I don't bother grinding it up, I just get the appropriate quantity for the sand being used, mix it with water, stir it around until it is thoroughly wet, and soggy, and mix it through the sand. Keep mixing, until it is evenly distributed, then, bingo! You have green sand.

    Curious to know - is cat litter a good source of bentonite? And what do you use it for?

    1 reply

    i dont know if its a good source but its cheep, I use it to make plugs in pyrotechnics and also for sandcasting.

    This design would work better if you could form four or more evenly spaced longitudinal (parallel to the axis of rotation) ridges on the inner wall of your drum. This would allow the grinding media (balls) something to grab onto to be dropped creating a smashing force, instead of sliding on the smooth wall of the drum. They need not be very thick. Think; inside of a clothes dryer.

    Perhaps an epoxy putty could be used. Or maybe heating the plastic drum to soften, then forming the bumps by pressing in from outside of the drum.

    Just a thought...

    1 reply

    not a bad idea that, epoxy putty would be good, or you could as you say heat the plastic up maybe with a heat gun then push something in it.

    for me this was a quick and dirty solution

    well i'm just using it as a clay for green sand so for that it was fine

    I need to make something like this. One question, why Lead balls? are they just easier for you to obtain or is the lead's softness needed?

    2 replies

    leads heavy and i had lead already, its easy to mould, plus at a later stage i will build a proper ball mill for pyro technics so i will need lead to prevent sparks

    the whole point of building this is that it was quick and easy for me to test what i needed to do, its not suppose to be a perminant ball mill.