Swede Posted April 23, 2010 Posted April 23, 2010 One of the very first major acquisitions any pyro makes, beyond the necessary chems, fuse, and tubes, is a decent ball mill. You can buy a rock tumbler, and it will work, but a much better option is to make your own. When I first joined APC, I did a blog on a basic ball mill that was designed to go together in literally a matter of hours by just about anyone. It uses all-thread rod (preferably stainless, two shafts, pulleys, plywood, and a motor. In the last couple of days, I did a retrofit of a conveyor-roller element that replaced two bearing blocks and a vinyl-covered steel shaft. The conveyor roller works spectacularly well compared to the expensive (and too stiff) traditional idler bar. So much so, I decided to blog it. There are no plans or kits for this mill, and none are required. It is pretty much self-explanatory. There are few tools a pyrotechnician can obtain that is more beneficial than a powerful ball mill of respectable capacity. Read about it here. http://www.5bears.com/firew/nbm06.jpg The goal - roll your own!
Fletcher Posted April 27, 2010 Posted April 27, 2010 (edited) how long did it take you to make? Edited April 27, 2010 by Fletcher
Arthur Posted April 27, 2010 Posted April 27, 2010 From my findings with mills (and rock tumblers! ) The drum diameter is important, and the bigger that you can get the diameter the better. I started with a 4" diameter jar and good milling took 12 hours and the batch was 200g. With a 8" diameter drum the same length as the original, (and more lead!) I can mill a kilo in 4 hours. Having a rubber drum means that during the day the noise is unnoticeable above traffic in the area so If I need powder I do a run 8 - 1 and a run 1 - 6 during the day and have enough for most things.
gordohigh Posted May 3, 2010 Posted May 3, 2010 (edited) Nice work Swede, I always enjoy your instructionals because you do such a nice job explaining things and the products are top notch !! I need to buy a few parts and build a new ball mill. I used to use my lathe with a piece of 1/2 in pvc as the driver but it was too much trouble moving it outside and my dual drum harbour freight tumbler is too slow. I am particularly interested in the motor you have, will definately check it out, thanks for taking the time for us all.. Edit.......Do you have the part number for that motor handy, they have quite a few pages of motors on that surplus site and I like the looks of the one you used, thanks. Edited May 3, 2010 by gordohigh
Swede Posted May 12, 2010 Author Posted May 12, 2010 I'm sorry, I don't have that exact motor number, and I think they may be out. It came with a switch, which was nice, and IIRC it is about 1/6 HP, which seems more than adequate. Pretty much any AC induction motor is going to be one of two speeds, either 3400 (approx) or 1700. With 50 Hertz mains, it will be slower. All you need is a single phase motor at the slower speed, a switch, and a pulley set to slow it down a bit. Anything from 1/6 on up should be OK. I'd be happier with 1/3 HP or greater. All the theory that goes into ball mill RPM's can really get people worked up, but if it isn't at a perfect RPM, it'll still do good work; it'll just take a bit longer is all. Anyway, those conveyor belt rollers are awesome for a ball mill. Those in the US can get them from Surplus Center. Those international just have to dig a bit and find a source. Good luck all.
Swede Posted May 12, 2010 Author Posted May 12, 2010 (edited) how long did it take you to make? With the hardware at hand, all it takes is to locate and drill the two plywood end plates. These are about 12" square. I used threaded steel inserts for the bearing block bolts, but there is no reason you couldn't use lag bolts, or bolts and nuts. To slap one together shouldn't take more than a few hours. You can pretty it up with plywood sheets and such, but the all-thread rod does a fine job. I did give the wood a few coats of NC lacquer to waterproof it. 90% of the work is in sourcing the components. Decide on the driven bar size you want to use; 12mm, 14mm, 1/2" or 5/8" and be sure the remainder of the hardware (pulleys and bearing blocks) match the driven bar - plus, the bar needs to be enveloped in vinyl tube or some other tacky rubbery tube to provide traction. Edited May 12, 2010 by Swede
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