playin4funami
noticing nice landscape pebbles
Member since March 2011
Posts: 87
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Post by playin4funami on Apr 15, 2011 15:28:45 GMT -5
no problem, got the pulley mounted and a belt installed. Have not got any pics yet or had time to do much lately, did run it for about an hour just to see how things went, it worked great, still need to do some things to it yet though. just used a 10 inch peice of pipe to test run it filled with stainless steel ball bearings like a ball mill, currently running at 70 rpm on the barrel. also have been thinking about building three smaller barrels so I can run different stuff at the same time, might still make a big barrel for big loads though.
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Post by connrock on Apr 16, 2011 7:22:56 GMT -5
I'm not sure what the right speed is for a 10" round barrel but my Thumler's Model B runs at about 28-30 RPM's wich leads me to believe that your barrel may be turning a little too fast??
connrock
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quartz
Cave Dweller
breakin' rocks in the hot sun
Member since February 2010
Posts: 3,341
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Post by quartz on Apr 16, 2011 21:44:34 GMT -5
Been thinking the same as connrock; run our 12" at 17, 10" at 28, and the 3 1/2" at 57 R.P.M. These speeds were arrived at by following recommendations in "Gem Tumbling and Baroque Jewelry Making" by The Victors, which was our starting point. Considerable experimentation showed about 20-25% slower than book value worked much better for us. We run near all quartz [pet wood incl.] in round barrels.
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playin4funami
noticing nice landscape pebbles
Member since March 2011
Posts: 87
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Post by playin4funami on Apr 18, 2011 9:41:54 GMT -5
Hmm thanks for the advice guys, I was going by another thread I had read somewhere recommending a higher speed, would you think that it mainly being a rough stage unit only machine it would work faster with a higher rpm or grind rock better at a lower rpm? I can swap out pulleys very easy due to my design, takes about 15 seconds so maybe I will rig up a larger quick release secondary pully and try that out also. my test spin was with a 10 inch ballel but the ones I am making are going to have a 12 inch running surface, don't know how big a difference thats going to make till I get one built, busy lately,lol.
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quartz
Cave Dweller
breakin' rocks in the hot sun
Member since February 2010
Posts: 3,341
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Post by quartz on Apr 19, 2011 9:30:07 GMT -5
What you want is a constant moving, clicking, tumbling [there's that word] sound. Too fast, the rocks will ride up the barrel and fall on the ones below, too slow will cause sliding that grinds flat spots on them. We set our speeds based on careful listening and the quality of product at each cycle change. Not to say the speeds I wrote above are perfect, but they work for us. Machines I've built for other people have proven very satisfactory using the figures I described. Connrock says his Model B runs at 28-30 R.P.M., our mid-size one is about the same dia., runs at the same speed, don't think we are too far off.
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playin4funami
noticing nice landscape pebbles
Member since March 2011
Posts: 87
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Post by playin4funami on Apr 20, 2011 13:30:31 GMT -5
great advice guys, I think I will need to slow it down then, and don't think I am not appeciating the advice, I certainly am, and you are saving me alot of "trial by error" mechanics and I thank you all. the rods will be covered with some automotive heater hose when I get to that part, which is a tough rubber hose that should work well. sure there will probably be some rebuilding in the future to "fine tune" this beast and it should provide many lbs of rough tumble material to send to the smaller 3 lb barrels for finishing. Also need to go out collecting pretty soon and see what agates and other goodies I can pick up for our glacial deposts, we have quite an assortment and the kids absolutely love the rock hunting part, as it may be their favorite part of the whole deal. other than showing off their finished rocks,lol.
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Post by connrock on Apr 21, 2011 7:44:20 GMT -5
After all is said and done and you think you have the right speed maybe you can make a temporary plexiglass cover and run a load with the right size rocks and just water to actually see what's going on inside there? As "quartz" mentioned listening to what's going inside the barrel is key but it's hard to explain what that actual "good' sounds is like. It's a nice "swooshing" sound and not a klickity clack type of sound,,,,,see what I mean about explaining that sound? LOL
Good luck,,,
connrock
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playin4funami
noticing nice landscape pebbles
Member since March 2011
Posts: 87
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Post by playin4funami on Apr 21, 2011 10:47:00 GMT -5
yeah I know the sound from my other tumblers, on them it seems to matter alot on the fill level in the barrels, to little material and they don't do near as good a job as when full to the right spot,lol. I think when I get around to it I am going to build one large barrel and also three smaller ones that can run at the same time, this should allow me alot of options, hopefully I get some time to mess with it this weekend. I am gonna slow it down a bit with a different pulley but keep the one I have on it now also, might make a good experiment to try a faster tumble on larger rough stuff to see what happens. and the speed might change under a full load load also? instead of turning an empty barrel?
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Post by connrock on Apr 22, 2011 7:14:13 GMT -5
Don't forget that even though you may try doing large rocks you still need a LOT of small rocks to get that surface contact needed!
I doubt you will see any difference in RPM's when the barrel is loaded.
The load in your barrel will actually weigh more when it's loaded with a lot of smaller rocks then it will with bigger rocks too! Fill a pick-up with as many huge rocks as you can,,,,weigh it. Now fill that same truck with pea gravel and weigh it!
connrock
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playin4funami
noticing nice landscape pebbles
Member since March 2011
Posts: 87
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Post by playin4funami on Apr 22, 2011 11:46:48 GMT -5
lol, yeah I don't think weight will be an issue, I think it is gonna handle anything I can throw at it as far as total weight of the barrel I am gonna build. I do want to do a few larger rocks but will probably only add a few bigger stones to each load so I don't loose surface contact. I have been adding a small handfull of BB size gravel to my 3 lbers for awhile as sacrificial rock and it helps alot. can't wait to get a tumble going in it but have other things right now that are forcing me to put it on the back burner for a few more days at least.
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Post by connrock on Apr 23, 2011 9:04:47 GMT -5
I wore out about 40-50 "Back Burners' before I retired! I wasn't using them at all now so I donated them to the young guy next door who seemed to need a couple more! LOL
connrock
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playin4funami
noticing nice landscape pebbles
Member since March 2011
Posts: 87
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Post by playin4funami on Apr 23, 2011 19:05:46 GMT -5
haha yes I know how that goes,lol. got to work on it for a few minutes today and cut some barrel sections, but forgot to take any pics, went rock picking yesterday, but good finds for tumbling media were few and far between, managed to pick up about two canvas sacks full for about 10 lbs altogether then went to leave and found a flat tire, and the lug wrench missing,grrrrr.
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