westcoastwelder
off to a rocking start
Member since September 2010
Posts: 16
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Post by westcoastwelder on Oct 5, 2010 18:39:41 GMT -5
Hi,
I'm about to assemble my first DIY rock tumbler, I just thought I'd run it by you to see if there's anything screaming out that's wrong. I'm going basically off of kriegh's plans, using a 2X6 w/ plywood base, and a hinged piece of ply for the motor to sit on with a bolt down to adjust belt tension. The motor is from a dryer, it will be re-wired for 120 (professionally) with a switch.
The barrel is a piece of SDR pvc sewer pipe, 8" in diameter. I am going to use epoxy and stainless steel screws to attach a flat plastic plate as one end cap and use stainless bolts into a nut that is epoxied into a recess in the pipe as the loading end. I am using a rubber pipe adapter that is roughly 3/16" thick to line the inside of the barrel, using plumbers glue to attach it, as well as a rubber circle cut exactly to size and glued into the end plate. The removable cap will have a rubber seal where it contacts the pipe as well as rubber covering the inner surface as well.
The drive and second shaft will be 5/8, and I recently decided to buy new bearings because the ones I have I don't think will hold up well. They are simply a band of brass or w/e inside the hole that the shaft will rub on continually for a month, not that good. I ordered some ball bearing assemblies that will be better suited to continuous duty.
The whole thing will fit inside an elevated box with sturdy legs to double as a work top for a lap machine or a hand cutting center for my angle grinder set up. It will be insulated as discussed to keep the barrel water from freezing in the potentially -40 temp in the unheated and uninsulated garage.
Questions I have: The length of the barrel, it is 8" diameter,, how long am I supposed to make it to be well balanced for the job etc? I have about a 14" long piece and more available.
This barrel will be rigid, will the design/structure be compromised with the vaccuum effect of the tumbled rock?
What kind of bearings are on everything else? The ball bearings were hard to find and specially ordered in, what is common?
Thanks guys, I'll take photos as I go and post pics (properly this time I swear) as I assemble.
Ryan
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Post by Hard Rock Cafe on Oct 5, 2010 19:21:23 GMT -5
Hi Ryan, There are several threads on here with home built tumblers. The only reason to line the barrels with rubber is to cut down on the noise. That will only last until the rubber gets worn away. The weight of the motor will probably provide enough tension. You can always add a bolt later if you need it. You might consider running threaded rod through the inside of the tumbler to hold the ends on. You'll get more compression (better seal) that way and they'll act as lifters for the rocks. You can sleeve them with PVC if you want. If you can get a PVC end cap it will be better than other plastic. As for the loading end, I use a test plug. I would not plan on doing anything else on the box while the tumbler is running because the tumbler will cause a lot of vibration. At -40, only adding heat will keep it from freezing. Some people put a styrofoam cooler over the tumbler with a light bulb inside. You'll want pillow block bearings. There are several bearing supply companies: www.mcmaster.comwww.grainger.comwww.thebigbearingstore.com/Your local home center can supply cold rolled steel for shafts, or you can order precision shafts (not necessary) form mcmaster or others. As for length, it depends on how much you can lift and the horsepower of your motor. I have a 10" diameter barrel that is roughly 2 feet long; that's too big. Start with your 14" pipe and see what you think. No need to worry about "vacuum effect" (in fact, I've never heard of it); your PVC will stand up to a lot of loads without trouble. Hope that helps, Chuck
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drjo
fully equipped rock polisher
Honduran Opal & DIY Nut
Member since May 2008
Posts: 1,581
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Post by drjo on Oct 5, 2010 19:38:50 GMT -5
Nice sniping job Hard Rock Cafe, that's what I get for correcting spelling ;D. I have Lortone with a 7.5" dia barrel that's 4.5" wide, otherwise it depends on how much you want to grind at one time (as long as the shafts can hold it up, the motor can turn it and you can afford to feed it ) 'This barrel will be rigid, will the design/structure be compromised with the vaccuum effect of the tumbled rock?" Are you speaking of the falling rock creating a vacuum? If so it doesn't happen like that in a closed system. You actually have to content with pressure build-up from several sources. "What kind of bearings are on everything else?" Small machines use nylon, delrin and what I think you were describing above is bronze bushings thru the chassis (I've services 40 yr. old printing presses with original bronze bushings still going strong, you just need to take care of them) ... Larger ones use pillow block ball bearings and a few use needle bearings (lab quality machines). If you live on our side of the planet bearings shouldn't be hard to find...then there is always ebay...1893 hits on 5/8" ball bearings, 79 on pillow block. Have you checked out all the designs in this section for tumblers? Dr Joe .
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Post by johnjsgems on Oct 5, 2010 21:31:00 GMT -5
As Dr. Joe said bronze bushings would work OK. That is what Highland Park/Contempo/Diamond Pacific used/uses on up to 65 lb. tumblers. Ball bearings would last longer. Bronze bushings are cheap and easy to replace.
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quartz
Cave Dweller
breakin' rocks in the hot sun
Member since February 2010
Posts: 3,339
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Post by quartz on Oct 5, 2010 21:51:17 GMT -5
Things I've experienced with the ten tumblers I've built; 3 for us and the remainder are with people I know: Use hanger bolts [fastener with wood screw on one end and machine screw on other, available from Fastenall, and others] to attach the removable end. Very doubtful epoxy will hold nuts for long. Most plastics don't glue well. Make the gaskets, I use truck inner tubes, in a ring shape instead of solid. I found solid gaskets wear thru in the middle and become a great grit catcher/holder. The 8" double barrel unit I built had plastic barrels 7 5/8" inside dia., 10 15/16" long gave 1 1/2 gallon capacity. Prefer building barrels to some even number for ease of grit measuring. The longer the barrel, the farther you end up reaching into the stuff to empty it. I have had no problems with unlined barrels, the plastic is quite abrasion resistant. All screw holes need to be pre-drilled, can't drive screws into plastic. Other bearing sources are Applied Industrial Technologies and U.S. bearings. Bronze bushings and babbit work fine, but must be regularly lubed. Look at page 4 for pics. of double 5-gallon unit I built for us. Not trying to pick you apart, sharing experience; the school of hard knocks is a wonderful teacher. Post some pics, always like seeing other peoples projects.
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Post by Hard Rock Cafe on Oct 5, 2010 22:06:10 GMT -5
Sorry Dr. Joe! Us DIY nuts have to stick together!
Chuck
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westcoastwelder
off to a rocking start
Member since September 2010
Posts: 16
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Post by westcoastwelder on Oct 13, 2010 0:27:01 GMT -5
OK so I am ready to assemble this thing, I've decided that my motor is strong enough to turn quite a few pounds of rock so I'm gonna stack the barrels in a way that they turn each other and I'll do the 4 stages at once. I have enough pipe and parts to do it so why not. I've also decided to use the rods as suggested to go through the end caps but I'm going to route them to the outside of the pipe so they don't touch the rocks and just have the caps oversize so they turn on the shafts at the ends and not on the pipe itself. I'll take photos as I go and try to update frequently, I'll most likely start this weekend. So you guys are sure that 8" of just the pipe (no rubber liner) will turn the rocks over alright, getting nice tumbling action? I'm just afraid of them sliding down the side and not tumbling over. I trust when you say you've had no problem you means it . Anyways thanks for the replies and tips, very much appreciated.
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drjo
fully equipped rock polisher
Honduran Opal & DIY Nut
Member since May 2008
Posts: 1,581
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Post by drjo on Oct 13, 2010 5:41:00 GMT -5
This could be a great tutorial.
If you are not happy with the tumbling action, you can always install some small PVC pipes or pieces (cut a piece of 1/2" PVC pipe long ways) inside the barrel with the solvent cement to create more action when tumbling.
Dr Joe
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Post by Hard Rock Cafe on Oct 13, 2010 8:14:17 GMT -5
I agree on the PVC pieces. I would do it before the first load, though, so that you have clean surfaces to glue.
I'm eager to see the pics!
Chuck
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quartz
Cave Dweller
breakin' rocks in the hot sun
Member since February 2010
Posts: 3,339
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Post by quartz on Oct 17, 2010 9:55:11 GMT -5
Your thought of stacking the barrels is a great space saver, running them parallel can take up lots of room really quickly. Personally, I don't agree with putting "kickers" in the barrels to get "more action" in the tumble, contributes to cracking and breakage in that large a tumbler. Proper speed will make the contents tumble quite well, you can hear it. Too slow, the rocks will slide; too fast, they will stick to the barrel then fall as they approach the top [breakage]. You want to hear a nice, even rolling and clicking sound. I would suggest about 22 R.P.M. for your barrels.
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