taongisurvivor
off to a rocking start
Member since March 2006
Posts: 6
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Post by taongisurvivor on Sept 7, 2013 14:46:23 GMT -5
I NEED HELP! I purchased 2 Model B tumbler's and 4 15-pound canisters approximately 10 years ago and they have really never worked properly. When I load a batch of rocks for tumbling, the canister will migrate over towards one of the plastic vertical bar "stops" on the rod. Then the edge of the canister will rub against the vertical stop. This will result in additional friction on the motor and belt, which causes the motor to get very hot and will eventually break the belt. This cycle will happen in less than 1 hour. Yes: the machines are level; the plastic guides are securely in the grooves at either end; the bushings are oiled; and the canisters are not warped. NO: the canisters are not overloaded. What is the deal?? I became so frustrated 8 years ago that I stopped doing this, but decided to clean the units up and have another try. Yep, within one hour the belts were broken. What is going on? I tried sending Thumbler an email asking for assistance but something is wrong with their www site. Has anybody else out there had this happen?
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Deleted
Deleted Member
Member since January 1970
Posts: 0
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Post by Deleted on Sept 7, 2013 17:15:03 GMT -5
I have a Model B and it rides near the plastic stops but not up to them and against. I'd say it sounds like the cutouts on the tumbler's frame are probably wider apart on the left than the right, causing the round barrel to ride to the left. Could you measure and see?
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taongisurvivor
off to a rocking start
Member since March 2006
Posts: 6
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Post by taongisurvivor on Sept 7, 2013 18:12:06 GMT -5
Just measured. One side center-to-center is 6 1/8 ( 6 and 8/64ths)" and the other is 6 and 9/64ths. Maybe just over 1/64ths difference. Enough to measure but hard to determine if this is the culprit. I elected to reduce the load to approximately 1/3 capacity of the canister and it has been running now for 3 hours without breaking. Maybe 5 pounds total rocks + water. So much for the advertised "15 pound capacity."
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Deleted
Deleted Member
Member since January 1970
Posts: 0
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Post by Deleted on Sept 7, 2013 19:32:25 GMT -5
Mine rolls perfectly fine with a full load. Are the roller bushings worn down inside?
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taongisurvivor
off to a rocking start
Member since March 2006
Posts: 6
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Post by taongisurvivor on Sept 7, 2013 20:03:08 GMT -5
Bushings are perfect. Going to wait until Monday then call Thumbler and talk with somebody. Again.
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quartz
Cave Dweller
breakin' rocks in the hot sun
Member since February 2010
Posts: 3,352
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Post by quartz on Sept 7, 2013 23:00:59 GMT -5
Suggestion: I've built and rebuilt several tumblers over several years. Never have liked the "rub bar" end thrust stops, for the reason you wrote. I've always made plastic rollers for the ends. This cuts way down on friction if a barrel rides against the stop. Not everyone has the ability to make them; I've seen several homebuilts using small casters mounted sideways for this purpose.
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Post by connrock on Sept 8, 2013 8:45:46 GMT -5
I've run 2 Model-B's for several years and even though I managed to get the barrels to center fairly well while running,I got fed up with their idea of side stop/guides. Just as "quartz" did,I made my own side stop/guides and all is well.
What I do to get the barrels to ride in the center and not hit the stop/guides may sound crazy to you but it's very easy to do and it won't hurt to try it.
With the barrel turning note what side the barrel is hitting a stop/guide.Put a single thickness of corrugated(brown) cardboard under the corner of same side of the frame,,,the side of the frame opposite of the motor. If this doesn't work try adding a single thickness of cardboard or something even thinner until the barrel centers itself. What I have found is that it's not the weight of the barrel or the entire unit being out of level,,,, that makes it move toward a stop/guide,,,,,,it's the barrel "screwing" itself on the rollers that causes it to move in that direction. By raising the barrel on the "problem side" the barrel can't "climb/screw" itself toward the stop/guides.
If the cardboard "shim" doesn't work by putting it under only 1 corner,,try putting some cardboard under both corners of the frame on the same side of the frame.
I use the cardboard as test "shims" and then swap them to thin pieces of metal as the cardboard tends to get "squeezed" down after the tumbler runs for a while.
I'm not a mechanical engineer and don't really know why this happens but I suspect it's because the rollers are not truly parallel to each other??
Good luck, connrock
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The Dad_Ohs
fully equipped rock polisher
Take me to your Labradorite!!
Member since September 2012
Posts: 1,860
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Post by The Dad_Ohs on Sept 8, 2013 11:12:36 GMT -5
I have the same issue with my Lortone QT66, but I went to the local thrift store and bought a set of roller blades for $2-3 dollars and pulled off the wheels, mounted 1 on each end so that which ever way the barrels shift they have a rotating wheel to stop them from hitting the edge & binding. Works like a charm!!
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quartz
Cave Dweller
breakin' rocks in the hot sun
Member since February 2010
Posts: 3,352
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Post by quartz on Sept 8, 2013 11:42:25 GMT -5
That's why roller blades work so much better than ice skates on pavement, applies to lots of other things too. connrocks method works too, but I had one that just wouldn't center no matter what, blamed the barrel itself. I use an inside micrometer to set shaft spacing, working within the roundness of the shaft cover. Larry
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taongisurvivor
off to a rocking start
Member since March 2006
Posts: 6
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Post by taongisurvivor on Sept 9, 2013 16:02:50 GMT -5
I called Thumbler this morning and talked with the owner. He was nice enough, but offered no advice or solution other than to make sure I oiled the motor. No "send it back and I'll send you another" or anything other than "I've sold thousands of these with no problems" and "you should have called me 10 years ago." Well, I can't remember, but I called somebody 10 years ago but I can't remember who but it probably was the dealer, not the factory. OK, my fault there. Also, when I told him his contact link on his www page did not work, his reply was "it never has." He seemed amazed when I told him that several other folks on this forum had the same issue, and stated that no one ever informed him of that fact. I don't find it a coincidence that neither the www site works and the owner of the company did not seem too interested in making it right and/or improving his product. If one thing is broke, it does not surprise me that the product won't work either. I could not sleep at night if I knew my www site was inoperative as that is a direct reflection on my company. Oh well, things have changed and not always for the better. It so happens that I purchased a serious bottle tumbler and the spacing on the horizontal rods may support the rock tumbler canister. It should be delivered today. If that works out, I will sell the Model Bs on Ebay then get on Amazon and give Thumbler a seriously marginal rating. Sigh......
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Post by connrock on Sept 10, 2013 9:54:37 GMT -5
Years ago before I retired I was running 9 rotary and 2 vibe units.It was pretty hectic trying to keep up with everything so I tried to think of ways to help me cut my "tumbling/maintenance" time down. One of the nastiest jobs that plagued me was cleaning that awful black oil residue off of the sides of the tumbler frames and plastic bearings/rollers. I tried all sorts of different oil and lubricants but still got the black "gunk"!
I took the rollers off of a Model-B,took the rubber off of the rollers and turned down the ends of both sides of the steel "shafts" to fit inside of 3/8" OD x 1/4" ID nylon tubing. The roller shafts would now have a nylon/nylon contact with the tumblers nylon bearings instead of nylon/steel contact. I applied a VERY thin coat of light oil to both the nylon bearings and the nylon on the shafts with a Q-Tip and ran this for several months without getting any black residue. I made detailed drawings of my changes to the shafts with specific details on the specs of the tubing I used,my running times using this idea,the type of oil,etc,etc,etc, and offered this to both Thumler's and Lortone FREE!
I never, to this day, have heard a single word from either of them!
They don't want to make changes in their designs because changes will cost them money and money is ALL they are interested in!
I KNOW my idea works and still have them on both of my Model-B's,,,,without any black muck!
connrock
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Post by johnjsgems on Sept 11, 2013 18:53:12 GMT -5
The "we have always done it this way" mentality is very common.
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