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Post by HankRocks on Nov 23, 2017 10:57:54 GMT -5
One of my Thumlers Model B has started stalling, I cleaned the pulleys and the belt - no change. The issue seem to be with the barrel itself moving towards the Guide on the idler shaft. As soon as the rim of the barrel contacts the Guide on the idler shaft it quickly comes to a halt. Tried some graphite on the Guide and on the barrel rim. I also tried leveling the base to keep the barrel from drifting, no luck as the barrel always seems to drift in the direction of the lid. That may be a barrel issue.
The Guides themselves are not completely aligned in a perpendicular plane to the shaft. Have tried lining them up with no success as one they are very difficult to move at all and slight adjustment are seemingly impossible as each adjustment just tilts it out of alignment somewhere else. Suppose I could rig up a standing guide that touches the center of the barrel on the lid end and keeps it from going into the guide itself, that will take a bit of doing to build and to drill the base of the tumbler to hold in place. Any suggestions?
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doublet83
starting to spend too much on rocks
Member since March 2016
Posts: 118
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Post by doublet83 on Nov 23, 2017 12:17:33 GMT -5
Yeah this happens to me too with the model B. I just put enough newspapers to raise one side of the tumbler and tweak around it it until the barrel stops moving to one side. (beyond just looking to level it)
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,175
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Post by jamesp on Nov 23, 2017 22:08:29 GMT -5
Yep, I run my rotaries on a slant. Been doing it for 8 years. I only have end rollers on one side. Tilt tumbler till barrel wants to hunt between end guides.
Not parallel shafts can create some serious steering forces. Does not take much out-of-parallel Or a barrel smaller in diameter on one side verses other. If system allows put bottom of barrel facing north instead of south.
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Post by HankRocks on Nov 24, 2017 7:54:25 GMT -5
Finally got the barrel to stop drifting by raising one side enough. The barrel still stops after a few rotations. Tested with another barrel on that base and it also stops, Both barrel run fine on the other base, so not a barrel issue. It's not an idler shaft issue so it must be somewhere in the drive assembly. cleaned both pulleys very well, new belt, same issue so it must be the driver shaft, maybe the rollers on the shaft. Bought replace rollers a few years back, but not sure how to change them out as they will not budge. Could cut the old ones off, but sliding the new ones on seems very difficult to do. Any ideas on how to slide those on easier without damaging them or the shaft?
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Post by captbob on Nov 24, 2017 8:29:19 GMT -5
Hey Henry,
I too have bought spare rollers, but seldom use them. I just buy the entire complete shaft(s) to have spares on hand. For less than 10 bucks for a complete shaft, it's not worth the hassle. To remove & replace rollers, I have used pliers and a hammer. Open pliers around the shaft standing shaft on end. Pliers around shaft against roller and tap with hammer to slide (force) the roller off.
Hate to even ask, but you do oil your white rollers on the end of the shafts frequently don't you?
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jamesp
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Member since October 2012
Posts: 36,175
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Post by jamesp on Nov 24, 2017 8:33:45 GMT -5
Finally got the barrel to stop drifting by raising one side enough. The barrel still stops after a few rotations. Tested with another barrel on that base and it also stops, Both barrel run fine on the other base, so not a barrel issue. It's not an idler shaft issue so it must be somewhere in the drive assembly. cleaned both pulleys very well, new belt, same issue so it must be the driver shaft, maybe the rollers on the shaft. Bought replace rollers a few years back, but not sure how to change them out as they will not budge. Could cut the old ones off, but sliding the new ones on seems very difficult to do. Any ideas on how to slide those on easier without damaging them or the shaft? I have slid rubber tubing on pipes using liberal doses of Dawn dish soap and heated hoses. One thing that helps with sliding rubber or plastic on a steel shaft is heat. Plastics and rubbers have high thermal expansion, steel does not. Crank up a pot of hot water on the stove to 130 to 150F and warm up the rollers as hot as your fingers can handle. The higher temperature will surprise you how it enlarges it. Add liberal soap and see how it goes. analogy, plumbing with sch 80 polyethylene tubing and barbed fittings. Take a hot air gun and heat the end of that totally rigid poly pipe and the barbed fitting will slide into it with little effort. soap helps but not necessary. Try the same stunt with the pipe cold and you will never get it on the barbed fitting.
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jamesp
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Member since October 2012
Posts: 36,175
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Post by jamesp on Nov 24, 2017 8:34:42 GMT -5
Buying the whole shaft with rubbers makes perfect sense as captbob mentioned.
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Post by HankRocks on Nov 24, 2017 8:43:34 GMT -5
Yes, I do oil the white bushings/bearing on the shaft ends periodically, it was the first thing I tried. Have tried the hammer and pliers method before, thought I was going to damage the shaft I was hitting it so hard. I might pull out one of my old driver shafts and see about rebuilding it as I have a new set of rollers. Wife's cousin has a better shop than I and with his assistance we can probably do a more professional job with it at his place.
If all that fails will order a new driver shaft. Thanks Henry
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Post by HankRocks on Nov 24, 2017 8:46:43 GMT -5
The heat method is a good idea, will try that later today. Thanks
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jamesp
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Member since October 2012
Posts: 36,175
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Post by jamesp on Nov 24, 2017 9:00:28 GMT -5
The heat method is a good idea, will try that later today. Thanks When heating them in water make sure you leave them in the water long enough for the heat to travel deep into the bushing. Even 120F water has a huge impact on making plastics and rubbers increase in size. Or for that matter hot tap water slowly running into a pot to keep temp elevated with the rubber bushings in the pot. After cooling heated parts like that are about impossible to remove lest you reheat. You can try the hot water trick on the shafts to remove the old bushings you were threatening to cut off to get an idea if the heat will help install them.
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Fossilman
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Member since January 2009
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Post by Fossilman on Nov 24, 2017 9:39:01 GMT -5
Lots of oiling and extra shafts on hand....I do the same here also...I don't like downed tumblers...
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jamesp
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Member since October 2012
Posts: 36,175
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Post by jamesp on Nov 24, 2017 10:05:37 GMT -5
Lots of oiling and extra shafts on hand....I do the same here also...I don't like downed tumblers... Spare parts is best way. 24/7 machines catch hard duty. IMO you can't have an over built rotary.
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