RogueRose
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Make LARGE ball mill (4 5gal buckets) with a treadmill & still be able to use treadmill as intended!
So I was trying to figure out how i was going to build a mill for a 5 gal bucket - or even up to 4 buckets at once. It would require a good bit of
building until I realized that I already had something that was 90% finished, had more power than I could ever need, very accurate speed control, was
professionally built (not a fire hazard) and didn't need to be taken apart. A treadmill!
So I thought of ideas on how this could work. I found some old wheels off a baby stroller at a thrift store, these are about 8" diameter x 1" wide,
the "tire" part is super nice soft grippy rubber and the tire is "domed" and gives about 1/8"-1/4" contact when sitting on edge with no weight. I
thought these would be great "drive wheels" for the mill. They would roll on the treadmill belt. They had a 3/8" hole in the center and they
glided/spun very nicely with little friction (it is a hard plastic of some kind). There is a 1.25" extruding ring surrounding the center hole with
the lip around the ring being about 5/8" high - so this would accept a 1.25" bearing perfectly inside of this and epoxy it in place. I'd do this for
all 4 wheels and these will all be in contact with the belt and will be the drive wheels for the buckets.
2 2x4 of about 7ft long will be used to hold the 4 drive wheels. holes will be drilled about 1/2" from the top of the 2x4's width (so about 1" of the
wheel is below the bottom of the board) on both boards, directly across from each other. I'll either use a metal rod (size of the ID of the bearing
hole) to hold the wheels and put nuts on the outside of the 2x4 to keep the rod in place. The width will be wide enough so that the buckets rest on
the 8" wheels - offset
I also have 8 roller blade wheels, 2 of which will be used for each bucket and they can be adjusted to accept smaller than standard 5 gallon buckets.
These wheels roll freely and are used to support the bucket and keep it in place.
There would be a few braces keeping the 2x4"s at proper distance apart. I mentioned an axel on the 8" wheels but those aren't 100% necessary, I did a
trial without them and it worked fine.
Now you will need to secure this setup so it doesn't slide off the treadmill belt when it is running, not hard to do, use a rope and clips to attach
to the vertical "beams" that the control rests upon. If you are worried about is sliding from side to side, it's possible to place a bumper on the
side of the treadmill (off the belt) where one would stand when waiting for the belt to slow/stop.
Here is a pic of the design. I've made a smaller model that can run 2 buckets and isn't near as sturdy as my final design.
[Edited on 7-25-2018 by RogueRose]
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CouchHatter
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That looks like it can handle a LOT of media!
If you can get ahold of paint or pickle buckets, they're a lot thicker than the hardware store brands.
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RogueRose
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Quote: Originally posted by CouchHatter  | That looks like it can handle a LOT of media!
If you can get ahold of paint or pickle buckets, they're a lot thicker than the hardware store brands. |
I don't know about pickle ones but I have some that coconut oil came in and it is very thick (maybe 120 mil vs 70 mil standard).
I didn't include the way to modify it so it can handle smaller bottles as well, like 1 gal bottles (ones maple syrup comes in is very thick walled).
I had build a couple mills and they were a PITA to change sizes and didn't work well with mixing sizes and having the motor be one speed, unless I
worked out a gear ratio. With this, I can put a pulley on the axel that connects the 8" wheels to turn the gallon jugs at a different speed. and
when it isn't being used it stands up in the corner with the treadmill (which collapses as well). It was free so I thought I'd give it a try.
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RogueRose
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I just found this seller on ebay that has some REALLY good prices on steel balls from carbon steel, chrome, stainless, etc in any size you might
realistically want in quantities from 10 to 10,000
https://www.ebay.com/str/BC-Precision/Slingshot-Ammo/_i.html?_storecat=745152719
I'm torn between getting steel balls or ordering aluminum oxide or Al2O3/ZrO balls or rods from china. The latter won't spark if I'm doing things
that are volitile, but you never know what you gonna get ordering from alibaba.
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Deathunter88
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For non-sparking you really want to be using lead media, not ceramic.
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Loptr
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Your arrows are going the wrong way. 
"Question everything generally thought to be obvious." - Dieter Rams
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RogueRose
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You won't believe how many times I switched the arrows thinking it was one way, then the other. But I am correct that each barrel will roll the
opposite way (when they are on the same drive wheel), correct?
Well if lead is best, I have plenty of it but I just need to make some moulds. I do have a couple 1.5" thick Al blocks (3" x 10" x 1.5") but IDK the
best way to drill a spherical hole. I think aga did something awhile back with a washer welded onto a bolt or something, but I fear I will have less
success, though I do have a drill press now instead of a hand drill, so that should help.
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Loptr
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In order for the arrows to go the opposite direction, something would have to be squeezing between the two buckets going up, otherwise, assuming the
tread is coming from the right, the left bucket would roll clockwise, and the right bucket would go counter clockwise.
[Edited on 26-7-2018 by Loptr]
"Question everything generally thought to be obvious." - Dieter Rams
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