Ball Mills

thecult:
i got the milling jar from that guy. The deal was quick and no hassle, but he only takes cheques.
Anyway, the tumble master looked about right, but with the barrel from it 1/2 full of lead media, it weighs about 4.5 kilos. which is more than the tumble master could handle.
Thats why i made my own. It probably works out about the same price to make one yourself, but you can make it to handle much heavier loads. Either way, its much easier to buy one, but you might have to load it less.

broadsword:
no sorry im not a fisherman, just find fishing line handy to have around! actually i think it might be good for spiking shells. its much "sharper" could kinda "cut" through the casing. i might try that sometime. anyone think it could work?

Edited by ProfHawking, 09 March 2005 - 12:12 AM.

Mr Cult wanted to know how i made this thing & what i used, but i thought i may as well post it here incase anyone else is interested. here is what i can remember:

milling jar - http://www.stonepolishing.co.uk/ - ?5
nice bog standard tube with caps. needs vanes glued to inside to break things up a bit.

motor - http://www.mainlineg.../mless/main.php - ?16
I got the "big motor" but thats probably not ideal, although i got it working, i think its a 3phase motor? there are extra wires that i dont know are for. It is slow spinning and high torque tho, hence my unusual gearing. you are probably better off with the "mains motor" and use a different gearing on the belt. (small to big, instread of big to small)

bearings - JJB sports - ?8
come as a pack of 8 for skateboards

go-cart tyre - random guy, sorry lost details. - ?4
i found someone from up north advertinsing tyres for ?4. this rolls nicely, and saves you from having to make ajustable rollers to switch between jar&tyre. However I havent tried rolling comps yet in it, so i dont konw how well it will work, but better than nothing im sure.

belt - http://rswww.com product id: 475-0232 - ?2.50
pullys - http://rswww.com id: 350-6286 & 350-6321 - ?2.90 & ?3.80
but you might want to change pulley ratios & belt length etc

other stuff used, you can get from any decent hardware store:
mdf board
M8 nuts & threaded bar (for the rollers. I used a latex/rubber type glue on them for grip)
screws etc
rubber strips & feet (for gripping motor & vibration limiting)
springs
steel wire
hinges

i got that lot from university stores so only cost me ?5 caus they buy in huge bulk. You might have to pay more.
I also made use of some heavy tools, like a lathe, bandsaw and milling machine.
You could probably get away with doing everything by hand except for the lathe. i dont know how you could machine the pulleys without one. I drilled them out and tapped one to fit on the M8 rollers, and used a grub screw to fix the other on the motor spindle. Might be tricky without a nice workshop. Im sure you could find one somewhere.

so adding all together ~= ?47
not too bad i suppose. still a little cheaper than buying one of the same spec. tho this one is more likely to break!

thanks for all of that, should be arther helpful.

One thing though, the '240v mains motors' is probally not the best one to use, in its Description is says "Looks quite powerful. Perhaps from a food mixer? "

If it did come from a food mixer then it wouldn't have been designed to run for long periods of time. So i will hvae a hunt around on that site and see if i cna find a motor for me.

Thanks again for all the info, wish me luck in building my ball mill.

TheCult

EDIT: I like the MR cult hehe

Edited by thecult, 09 March 2005 - 09:03 AM.

Thanks ahead of time for your help and useful post, both Burlhorse and Lloyd E. Sponenburgh for speedy and extremely helpful emails.

After attempted use of a dual drum rock tumbler that failed miserably... My BP quality was garbage so Im finally getting around to building my own mill.

If anyone else decides to get the same drum as I did you have your calculations already done right here. I have the same drum from there > http://www.unitednuclear.com/mills.htm its the 15lb capacity drum, except I didnt spend $75 on it.

I got the drum in measured it and found it to be 29.25" circumference. So Pi*D=C. 29.25/Pi=9.31 diameter. My rollers are 1.5" diameter, as per recomended by Burlhorse, which gives it a 4.71" circumference.

29.25/4.71=6.21 which then equals the number of rotations the roller has to rotate for the drum to rotate once. For myself I was utilizing a 6" ID drum with 1/2" media so according to Ball Milling Theory and Practice by Sponenburgh my optimum rpm for the drum is 73. So 73*6.21= 453rpm at the roller for the drum to reach 73 rpm.

My motor runs at 1725 rpm. 1725/453=3.81 reduction. The ratio is 3.81:1 if I am utilizing a 1" pulley at the motor. So for a 3L belt I need a pitch diameter of 3.81" for the roller pulley and 1" at the motor pulley. Closest I found was 3.86" pitch diameter and 1.05" pitch diameter. This is a ratio of 3.86:1.05 which equals 3.68.

As Burlhorse said work backwards to check work. 1725rpm/3.68=468.75 which is the actualrpm at the rollers. 468.75*circumference of roller=2208.932 inches the roller travels in one minute. 2208.932/circumference of jar= 75.5 rpm.

That is only 2.5 rpm over optimum, Lloyd said it was no problem so I dont mind. Unfortunately I was unable to find 1/2" hardened lead media I found 1" hardened lead media. The optimum rpm for a 6" jar with 1" media is 77, even better only 1.5 rpm off!

Will have parts by monday and everything finished within 2-3 weeks.

If anyone has questions for builidng their own mill I would be more than willing to help.

italteen3 - I'm considering building a mill along the same lines as you, so here are a couple of questions:

According to several earlier posts in this thread you ought to about half fill the drum with media. Your drum has about an 8,5 liter volume. If you half fill this with lead spheres (packing fraction about 70%) this translates to about 3 liters of lead which is about 34kg (!!!!) of lead media - this LARGE mass excludes the mass of stuff you are milling.

So the questions are:
Are you actually going to fill over 30kg of lead into your machine??
Where do you buy your 1 inch hardend media and what's the price?

Oh - and you say the drum you got is the same as unitednuclear sells for 75$, but you got it for less? -Care to share how you got it cheaper?

BTW. I wonder what "15lbs" refers to when you load about 80lbs total into the drum?

Cheers,
Peter

italteen3 - I'm considering building a mill along the same lines as you, so here are a couple of questions:

According to several earlier posts in this thread you ought to about half fill the drum with media. Your drum has about an 8,5 liter volume. If you half fill this with lead spheres (packing fraction about 70%) this translates to about 3 liters of lead which is about  34kg (!!!!) of lead media - this LARGE mass excludes the mass of stuff you are milling.

So the questions are:
Are you actually going to fill over 30kg of lead into your machine??
Where do you buy your 1 inch hardend media and what's the price?

Oh - and  you say the drum you got is the same as unitednuclear sells for 75$, but you got it for less? -Care to share how you got it cheaper?  

BTW. I wonder what "15lbs" refers to when you load about 80lbs total into the drum?

Cheers,
Peter

Alright glad I can help! First you say my drum has an 8.5 liter volume. Not sure how you came about that but it seems a bit much. The company I got it from claimed a tad under 1 1/2 gallons or about 5.5 liters. That seems right as I can just fit a gallon jug into it that is taller than my jar.

Yes you are correct you are supposed to fill the jar 50% media and 25% charge. The media is actually 1" cylinders, with rounded edges, for $65. I am not sure of the total weight, I have to call the supplier. Im going to buy it at hobbyfireworks.com

I honestly cannot remember the place I got it for cheaper. If I could find the website I would gladly let you know.

The 15lb thing at united nuclear refers to what the motor on the tumbler they sell can handle. Im using a 1/2hp motor which should hopefully be able to handle around 60 lbs worth of media, jar, charge, etc.

Yay! Easter coming up! I will have 4 days to get my ball mill started. I have a motor and jar and only need everything else!

Yay! Easter coming up! I will have 4 days to get my ball mill started. I have a motor and jar and only need everything else!

The everything else is still a lot. If you can get all you need and build in 4 days I will be impressed.

It was meant to be a joke. I am well known for my poor sence of humor.

Be impressed Andrew! I have made my ball mill in TWO days!

Its got a pretty weak motor so I can only mill small batches at a time. As I have no spark proof media I have to mill fuels and oxidiser seperately, but it beats the mortar and pestel by a long shot!

Be impressed Andrew! I have made my ball mill in TWO days!

Its got a pretty weak motor so I can only mill small batches at a time. As I have no spark proof media I have to mill fuels and oxidiser seperately, but it beats the mortar and pestel by a long shot!

I'm well impressed. It took me two whole weekends of bodging to complete my first mill.

Have you got any pictures?

Dont you need to have your own site to do that? I have a digital camera but no way of puting thom on here. and by the way, I cant figure out how you edit your posts. How do you do it?

Dont you need to have your own site to do that? I have a digital camera but no way of puting thom on here. and by the way, I cant figure out how you edit your posts. How do you do it?

Simply click the edit post button at the bottom right of your post.

Thanks!

Hey, i just bought a ball mill and started off by milling some little clay pieces so that i can use them later for nozzles, and because its raining outside so i wanted to mill something safe if i was going to do it inside...

anyway, while i was milling, i heard that after a minute, what would happen is that you could hear the balls roll, then silence for a moment, then roll, then silence, then roll.... seems like theyre not continuously rolling, but rather they are staying in place until they get high enough up the side of the container, and then roll to the bottom... is this correct? if so, is it a problem? what should i do to fix it? add more media, take media away? any help would be appreciated

sorry if it has been discussed before, i tried a search but didnt know what to search for...