steveinnmi
off to a rocking start
Petoskey, MI
Member since February 2015
Posts: 9
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Post by steveinnmi on Feb 7, 2015 11:30:56 GMT -5
I have been collecting small rocks for a long time but have never done anything with them until now. My rocks are usually local ones I've picked up while walking or while on vacation to other places. I have never tumbled rocks before so this is all new to me. I had an electric motor, (2) 5/8" shafts and (4) bearings so I thought building a tumbler rather than buying would be a good way to start. As it turns out I probably should have just bought a small tumbler but I didn't so here I am now trying to get the finished product up and running. I have been looking at other tumblers that your members have built so I fashioned mine using others designs and I believe it is working quite well but I have a few questions I would like some help with. 1) Best RPM's- My 4" pvc barrel is turning around 43 RPM's when sitting on the bare shafts or about 58 RPM's when sitting on the rubber tubing that I have slid on the shafts. 2) The size of the barrel- I would like to do small loads to start with until I get the process down and so I'm not wasting grit and polish. The barrel I made is 4" pvc 12" long. I was hoping for a barrel that would hold about 3# or less. I used a 16oz (1#) cottage cheese container to measure with and put 3 of these in my barrel filling it about 1/2 to 2/3rd full. It seems like more than 3# in the barrel. I don't have a scale that would measure a pound so I'm just guessing. What would be a good way to estimate the amount of rocks I'm using?
I tried to post some pictures but I'm getting an error so I'll have to see how to do this later. I think they are to large.
Steve
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Post by captbob on Feb 7, 2015 11:52:18 GMT -5
Not too sure about the specific gravity of cottage cheese, but... a container that holds 16 oz of cottage cheese is going to hold much more in rocks. I don't know the size of your rocks, but if they are smalls and not leaving a bunch of voids (air space) in the container, I'd guess at least 3 pounds of rock per container - maybe more.
Your barrel is turning WAY too fast. Like 3 or 4 times too fast. You are going to need to change out the drive pulley to reduce your RPMs.
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Post by captbob on Feb 7, 2015 12:00:17 GMT -5
Put in a load of rocks and empty them in a plastic bag. Take the bag to your local grocery store (maybe stash it in your wife's purse) and throw it on a scale in the produce department. That outta give you a good idea on your average load weight - BEFORE adding water and grit.
A cup of water weighs 8 oz. So if you add two cups there's another pound.
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steveinnmi
off to a rocking start
Petoskey, MI
Member since February 2015
Posts: 9
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Post by steveinnmi on Feb 7, 2015 12:07:09 GMT -5
Not too sure about the specific gravity of cottage cheese, but... a container that holds 16 oz of cottage cheese is going to hold much more in rocks. I don't know the size of your rocks, but if they are smalls and not leaving a bunch of voids (air space) in the container, I'd guess at least 3 pounds of rock per container - maybe more. Your barrel is turning WAY too fast. Like 3 or 4 times too fast. You are going to need to change out the drive pulley to reduce your RPMs. captbob, thanks for the reply. So what RPM's should I be trying to obtain? 20 or 30? Steve
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Post by captbob on Feb 7, 2015 12:12:36 GMT -5
We have a member here, jamesp, and he is a master at these PVC barrels. He's out freezing his butt off rock hounding today, but he's the guy to answer this. I'd guess that you are looking for less than 20 RPM on the barrel. Someone will be along to answer for sure. Many are busy on weekends, so it's kinda slow today. So check back. And, welcome to the forum! Lots of folks here doing the same stuff you're getting started on, so stick around.
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Post by Jugglerguy on Feb 7, 2015 12:58:39 GMT -5
Hi Steve. I'm over in Alpena. Besides jamesp, Drummond Island Rocks might be able to give you some advice on homemade tumblers. I just went down and timed my tumblers. My Lortone 33b has a 4.5 inch diameter barrel that runs at 46 rpm. My Lortone QT66 has a 7.75 inch diameter barrel that runs at 23 rpm. I know the speed varies some due to belt wear and load (these were fully loaded). I had worn out plastic bearings on my 33b said while ago that really slowed them down. So my speeds may not be perfect. You're not trying to tumble Petoskey Stones, are you?
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steveinnmi
off to a rocking start
Petoskey, MI
Member since February 2015
Posts: 9
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Post by steveinnmi on Feb 7, 2015 13:28:05 GMT -5
Hi Steve. I'm over in Alpena. Besides jamesp, Drummond Island Rocks might be able to give you some advice on homemade tumblers. I just went down and timed my tumblers. My Lortone 33b has a 4.5 inch diameter barrel that runs at 46 rpm. My Lortone QT66 has a 7.75 inch diameter barrel that runs at 23 rpm. I know the speed varies some due to belt wear and load (these were fully loaded). I had worn out plastic bearings on my 33b said while ago that really slowed them down. So my speeds may not be perfect. You're not trying to tumble Petoskey Stones, are you? Jugglerguy, I'm not tumbling Petoskey Stones. At first I'll try tumbling stones I've found around my house. I'm not sure exactly they all are but most are like Basalt Granite and a few pudding stones. I'd attach some pictures but I keep getting an error when I try.
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Post by Jugglerguy on Feb 7, 2015 20:03:02 GMT -5
I use Flickr for my pictures. There's almost unlimited space for free. To post here, select your photo in Flickr, click the curved arrow in the bottom left corner and select "BBCode". Copy and paste the code here.
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,155
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Post by jamesp on Feb 7, 2015 20:53:45 GMT -5
A small barrel is fine at those two speeds Steve. Bigger diameter barrels need to be slower. Obsidian and glass are best run slower. Basalt and puddingstone and agates should be fine. welcome to the forum
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steveinnmi
off to a rocking start
Petoskey, MI
Member since February 2015
Posts: 9
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Post by steveinnmi on Feb 8, 2015 10:08:22 GMT -5
A small barrel is fine at those two speeds Steve. Bigger diameter barrels need to be slower. Obsidian and glass are best run slower. Basalt and puddingstone and agates should be fine. welcome to the forum jamesp thanks for the reply. I think I'm ready to give the tumbler a try. With the 4" barrel should it be filled 2/3rd or so full? I haven't put any lifters inside the barrel.
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steveinnmi
off to a rocking start
Petoskey, MI
Member since February 2015
Posts: 9
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Post by steveinnmi on Feb 8, 2015 10:14:31 GMT -5
Put in a load of rocks and empty them in a plastic bag. Take the bag to your local grocery store (maybe stash it in your wife's purse) and throw it on a scale in the produce department. That outta give you a good idea on your average load weight - BEFORE adding water and grit. A cup of water weighs 8 oz. So if you add two cups there's another pound. captob, I borrowed a scale and now have a good idea of what 1lb of rocks is. I had to resize my barrel a little so I could have 3# of rocks fill the barrel around 2/3rd full.
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,155
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Post by jamesp on Feb 8, 2015 10:49:44 GMT -5
A small barrel is fine at those two speeds Steve. Bigger diameter barrels need to be slower. Obsidian and glass are best run slower. Basalt and puddingstone and agates should be fine. welcome to the forum jamesp thanks for the reply. I think I'm ready to give the tumbler a try. With the 4" barrel should it be filled 2/3rd or so full? I haven't put any lifters inside the barrel. It is the surface speed that counts Steve. 4 X 3.1415 X 43 Rot/min = 540 inches per minute 4 X 3.1415 X 58 Rot/min = 728 in per minute My 6 inch PVC barrels run at 600-1000 inches/minute. 728 in a small 4 inch barrel should be fine for about all except maybe glass. And fine for glass if you use filler. Good luck on your endeavor. I would keep the length under 10 inches for good width to diameter ratio for grit mixing. They should last a lifetime. I do run my PVC on straight steel, but both shafts are driven. But it makes more noise on straight steel...
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steveinnmi
off to a rocking start
Petoskey, MI
Member since February 2015
Posts: 9
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Post by steveinnmi on Feb 8, 2015 11:32:50 GMT -5
I use Flickr for my pictures. There's almost unlimited space for free. To post here, select your photo in Flickr, click the curved arrow in the bottom left corner and select "BBCode". Copy and paste the code here. First attempt to post pictures with Flicker. 1st pic is the barrel sitting on the tubing. This will turn at around 58 RPM 2nd pic is the barrel sitting directly on the steel shafts and will turn the barrel at around 43 RPM. 3rd pick is the machine showing the belt to drive the other shaft
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Post by Jugglerguy on Feb 8, 2015 13:11:02 GMT -5
That looks like a solid machine. Choose a larger size when you post your pictures. I also delete everything outside the img tags, just to clean it up, but you don't have to do that.
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Post by Jugglerguy on Feb 8, 2015 13:20:24 GMT -5
Steve, I dont know what type of rock you're collecting, but chert tumbles well and there's some pretty nice stuff in Norwood, which is near you. Norwood ChertHere is my Petoskey trip report from last year. We had much better luck looking for Petoskeys in Alpena later in the summer.
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steveinnmi
off to a rocking start
Petoskey, MI
Member since February 2015
Posts: 9
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Post by steveinnmi on Feb 8, 2015 14:04:55 GMT -5
Steve, I dont know what type of rock you're collecting, but chert tumbles well and there's some pretty nice stuff in Norwood, which is near you. Norwood ChertHere is my Petoskey trip report from last year. We had much better luck looking for Petoskeys in Alpena later in the summer. Rob, the Norwood Chert are beautiful I'll have to visit there this spring to see what I can find. I was fooling around with the Flickr account and managed to delete the pictures. I'm a little computer challenged. Here are the rocks I plan to try first. Steve P1050910 by steve in n mi, on Flickr
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,155
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Post by jamesp on Feb 8, 2015 18:17:01 GMT -5
Steve: You can also stick a 4 to 3 inch reducer bushing in the coupling, and then a short stub of 3 inch pipe. That would allow a band clamped rubber cap, and 3 inch hole for an opening. these 6 inch with 6 to 4 inch reducing bushing, 4 inch stub pipe to accept rubber cap.: rubber cap:
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Post by Jugglerguy on Feb 8, 2015 20:54:41 GMT -5
I tumble mixed beach rocks from Lake Superior a lot. Some will turn out nice and others will be disappointing. Granite will get shiny, but the black parts will undercut. People go nuts for pudding stone. The jaspers will get super shiny, but the matrix will always have little holes all over. I have some small pieces of pudding stone in the tumbler now that I'm making beads from for a friend. Keep your eye out for unakite. It's red and green. It's about the only green rock you'll find. It shines up really nice. I haven't found too much in Lake Michigan, but there is some. Quartz will shine up nice, but it almost always has fractures all through it.
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steveinnmi
off to a rocking start
Petoskey, MI
Member since February 2015
Posts: 9
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Post by steveinnmi on Feb 9, 2015 21:16:05 GMT -5
jamesp,thanks for the pictures of your tumblers/barrels. That gives me a lot of great possibility's. I think I'd like to try the rubber caps you are using. Steve
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steveinnmi
off to a rocking start
Petoskey, MI
Member since February 2015
Posts: 9
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Post by steveinnmi on Feb 9, 2015 21:23:37 GMT -5
I tumble mixed beach rocks from Lake Superior a lot. Some will turn out nice and others will be disappointing. Granite will get shiny, but the black parts will undercut. People go nuts for pudding stone. The jaspers will get super shiny, but the matrix will always have little holes all over. I have some small pieces of pudding stone in the tumbler now that I'm making beads from for a friend. Keep your eye out for unakite. It's red and green. It's about the only green rock you'll find. It shines up really nice. I haven't found too much in Lake Michigan, but there is some. Quartz will shine up nice, but it almost always has fractures all through it. Rob, were you referring to the rooks in my picture I posted? Guess I'll have to study a bit. Steve
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