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Post by deb193redux on Oct 16, 2016 19:57:18 GMT -5
I am running the local club's C-40. It has been refit a few time by past members. Currently the RPM seems very slow because the large pulley is 10". I notice the new ones come with a 5" large pulley.
So what is the ideal barrel RPM?
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Post by orrum on Oct 16, 2016 20:35:07 GMT -5
Jamesp the madman tumbler needs to weigh in and also Chuck where r u?
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Post by Drummond Island Rocks on Oct 16, 2016 20:50:37 GMT -5
What is the current barrel rpm? With that barrel diameter I would expect somewhere between 20 and 30. Best bet is to have someone with a stock C40 tell you what they run at.
Chuck
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Post by glennz01 on Oct 16, 2016 20:51:09 GMT -5
I am running the local club's C-40. It has been refit a few time by past members. Currently the RPM seems very slow because the large pulley is 10". I notice the new ones come with a 5" large pulley. So what is the ideal barrel RPM? 30 rpm mine is stock
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Post by deb193redux on Oct 16, 2016 21:13:28 GMT -5
Thanks for replies. I am getting 26 RPM. I timed 30 revolutions at 1:16, or 72 seconds. The drive pulley is smaller than stock, and the driven pulley is larger. I think I might adjust both because right now the belt is very close to roller. (Actually, this could be Diamond Pacific).
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Post by deb193redux on Oct 16, 2016 21:15:40 GMT -5
Yes, it is Diamond Pacific. The pulleys do appear to be stock. I might leave well enough alone.
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Post by Drummond Island Rocks on Oct 16, 2016 21:36:39 GMT -5
26 sounds fine for that diameter barrel. If it were only used for stage one I am sure you could bump up the speed but I have never bothered.
Chuck
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Post by glennz01 on Oct 16, 2016 23:51:26 GMT -5
its a lortone... i'd just leave it alone
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jamesp
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Post by jamesp on Oct 17, 2016 6:10:43 GMT -5
That's a big barrel. 26 RPM for a 12 inch barrel = 52 RPM for a 6 inch barrel which is plenty fast. Actually fast for finishing, perfect for roughing.
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Post by glennz01 on Oct 17, 2016 12:13:03 GMT -5
That's a big barrel. 26 RPM for a 12 inch barrel = 52 RPM for a 6 inch barrel which is plenty fast. Actually fast for finishing, perfect for roughing. Comparing the 2 like that doesn't quite work that way... If you look at effectiveness and compare the numbers (9*12/40)26 = 70.2 so for a small barrel to have the same effectiveness that would have to be 70.2*4/(3.5*6) = 13.37 rpm or for a 12 barrel that would be 13.16 rpm which is about right for a 12 lb which is half the size so you would be overworking a 4 lb barrel to expect it to have the same efficiency as a 40 lb barrel.
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jamesp
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Post by jamesp on Oct 17, 2016 13:37:06 GMT -5
I have run 6-8-10-12. For all around coarse and finish work on Mohs 7 single speed I like 40-35-30-25 at most. Better is 30-25-23-20 for best results glennz01. I will stick to 26 for the big one for coarse, 20 for finish. Many factors could effect those numbers like media padding slurry etc. But Glenn, I do 55 on 6 inch in coarse or 30 in coarse depending on material and size of. 30 on 6 in finish steps. And don't use the big barrels any more. I find them to bruise easier. And if stuff goes wrong a lot of rocks are at risk. Would much rather have two 20 pound barrels. That's just me and my way. Not so much a math derrivitive but from experience.
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Post by glennz01 on Oct 17, 2016 13:55:48 GMT -5
I have run 6-8-10-12. For all around coarse and finish work on Mohs 7 single speed I like 40-35-30-25 at most. Better is 30-25-23-20 for best results glennz01 . I will stick to 26 for the big one for coarse, 20 for finish. Many factors could effect those numbers like media padding slurry etc. But Glenn, I do 55 on 6 inch in coarse or 30 in coarse depending on material and size of. 30 on 6 in finish steps. And don't use the big barrels any more. I find them to bruise easier. And if stuff goes wrong a lot of rocks are at risk. Would much rather have two 20 pound barrels. That's just me and my way. Not so much a math derrivitive but from experience. I'd have to try but that just seems a bit fast to me.
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jamesp
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Post by jamesp on Oct 17, 2016 16:33:21 GMT -5
I have run 6-8-10-12. For all around coarse and finish work on Mohs 7 single speed I like 40-35-30-25 at most. Better is 30-25-23-20 for best results glennz01 . I will stick to 26 for the big one for coarse, 20 for finish. Many factors could effect those numbers like media padding slurry etc. But Glenn, I do 55 on 6 inch in coarse or 30 in coarse depending on material and size of. 30 on 6 in finish steps. And don't use the big barrels any more. I find them to bruise easier. And if stuff goes wrong a lot of rocks are at risk. Would much rather have two 20 pound barrels. That's just me and my way. Not so much a math derrivitive but from experience. I'd have to try but that just seems a bit fast to me. I learned that going from 6 to 8 makes a big difference. Moving up to 10 or 12 even more so. The 40 pounder has an octagonal barrel which allows higher speeds I believe. Look at the avalanche on the top of the barrel where most of the grinding action is. a 12 inch barrel has twice the length of slope as a 6 inch barrel.
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Post by glennz01 on Oct 17, 2016 18:11:19 GMT -5
I'd have to try but that just seems a bit fast to me. I learned that going from 6 to 8 makes a big difference. Moving up to 10 or 12 even more so. The 40 pounder has an octagonal barrel which allows higher speeds I believe. Look at the avalanche on the top of the barrel where most of the grinding action is. a 12 inch barrel has twice the length of slope as a 6 inch barrel. I know that the octagonal barrels help to force rocks to move around and tumble down the slope. Lortone 3lb barrels also have the same principals in them. At higher speeds i'd think the rocks in small barrels would try to stick to the outside of the barrel at least at 50 rpm... not sure how to really modify a tumbler to get to that speed easily as well.
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jamesp
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Post by jamesp on Oct 17, 2016 18:26:11 GMT -5
Not sure about 3 pound barrels but 6 inch barrels at 55 do fine glennz01. Not enough centrifugal force to make them stick to the walls.
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Post by glennz01 on Oct 17, 2016 19:58:13 GMT -5
Not sure about 3 pound barrels but 6 inch barrels at 55 do fine glennz01 . Not enough centrifugal force to make them stick to the walls. I might have to play around with my smaller tumblers some time then
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jamesp
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Post by jamesp on Oct 17, 2016 21:54:29 GMT -5
Not sure about 3 pound barrels but 6 inch barrels at 55 do fine glennz01 . Not enough centrifugal force to make them stick to the walls. I might have to play around with my smaller tumblers some time then Been running the 6 inch PVC barrels 3-4 at a time for 4 years. I know them well. Have 2 sets of shafts each with 2 speeds and tinker a lot w/speeds.
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Post by glennz01 on Oct 17, 2016 23:08:40 GMT -5
Ah I see, I was thinking a standard thumblers or lortone... I do have an old base from a 40s or so tumbler that I can get running some day.
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jamesp
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Post by jamesp on Oct 18, 2016 5:09:33 GMT -5
Ah I see, I was thinking a standard thumblers or lortone... I do have an old base from a 40s or so tumbler that I can get running some day. Nothing wrong with Lortone barrels. I have a 12 pound. I find the seal takes effort to clean well before sealing it back up. Occasionally leaks. This is my tumbler. 55 RPM on back shafts, 30 RPM on front shafts. The left rear barrel and the front two right barrels are not finished yet.(they are bouncing and need the lip ground off) All barrels empty except the big barrel. You can hear a steady but fast rumble. The bigger barrel is 4 years old.and note that it's rubber end cap bulging due to some gas build up. Those caps come off quick and easy for pressure releases, clean outs, grit additions and slurry adjustments. Four finished barrels running on 55 RPM shaft. All full of rocks. Sounding correct, steady smooth rumble with no knocking. Nice heavy slurry, SiC 30 grit will be used up by morning and ready for fresh SiC 30 and clay slurry thickener. Each barrel has a 1-2 pound rock in it yet no knocking. May sound like it, but not. The PVC is telling, noisy albeit, but makes sound that lets you know if rocks are grinding gently.
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Post by glennz01 on Oct 18, 2016 12:43:12 GMT -5
That looks like something I need... but for 4 barrel sizes
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