rallyrocks
fully equipped rock polisher
Member since November 2005
Posts: 1,507
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Post by rallyrocks on Mar 1, 2007 22:12:10 GMT -5
I don't know what is going on, but most of the belts I've bought lateley do not seem to be fitted right for my expando drum, they are all REALLY loose, to the point where they will walk right off the wheel and go flying across the room, that is- if they don't go off kilter and tear themselves to pieces first.
Do drums get tired of expanding?
Or have 3M and eastwind just lost track of the actual circumference of a 6" wheel?
I am pretty much dead in the water until I find a working solution, as there is only so much you can do with two hard wheels at 80 and 220, and only one belt at 3000 that will stay put......
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Post by rockds on Mar 1, 2007 22:49:14 GMT -5
Is buying nova wheels out of the question?
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Post by parfive on Mar 2, 2007 0:21:24 GMT -5
Have you got an old, useless belt lying around? Cut it side to side so it's now a strip, and put it inside the one you want to use. Or pad the inside of the belt with a strip of something else.
Rich
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agatemaggot
Cave Dweller 
Member since August 2006
Posts: 2,195
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Post by agatemaggot on Mar 2, 2007 1:10:46 GMT -5
I purchased some used expanding wheels at an auction recently and had the same problem
After struggling for several weeks I put a little bit larger pulley on my motor to try a little faster speed on the wheels.
That dun it!!!!!!
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Post by stoner on Mar 2, 2007 1:27:42 GMT -5
Well if you have loose Eastwind belts consider yourself lucky. The ones I got from them are so tight that I tore the edges trying to put the on and take them off. And, they don't last very long either. From now on when I buy belts I'm buying Raytec's True Circle belts. They have a mylar backing on them and are much better quality. But with your problem, speeding up the machine a little bit will take care of it.
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rallyrocks
fully equipped rock polisher
Member since November 2005
Posts: 1,507
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Post by rallyrocks on Mar 2, 2007 10:23:59 GMT -5
Is buying nova wheels out of the question? Well, given that they cost 110 bucks each, (320,400,600,1200,3000,8000,14000,50,000, I'd be looking at about a grand) and involve a wrench every time I change them, they really are not an option at this point. But I do have other pulleys and plenty of gaffers tape, I'll see what I can do to back them up and spin them a bit faster. Thanks for the suggestions! |
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stefan
Cave Dweller
Member since January 2005
Posts: 14,113
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Post by stefan on Mar 2, 2007 10:32:33 GMT -5
This sounds corny- But when was the last time you cleaned your drums??? I take mine off every 6 months or so- take em outside and hit them with the air compressor (about 50 to 75 psi) I'm amazed at the accumilation of dust in them! Then I rinse em off woth the hose and pop em back on- My drums are Ancient (Scott Murray brand) and they hold the belts as tight as can be!
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rallyrocks
fully equipped rock polisher
Member since November 2005
Posts: 1,507
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Post by rallyrocks on Mar 2, 2007 11:40:31 GMT -5
Another good suggestion, thanks Stefan- I have been spinning this one a whole year now, so you could very well be onto something there- I also have an extra expando wheel I'll try tonight
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Post by freeform on Mar 2, 2007 13:00:49 GMT -5
drums can wear out, but like any rubber, you'll notice rot and cracks in the rubber. If that the case it is time to get a new drum. Also depending on who sold you the belts. There are exact fit belt, and expando belts. thats why in my opinion its always best to buy such items from actaully lapidary suppliers, vers a rockshop or online rockshop which sells a bit of everything.
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rallyrocks
fully equipped rock polisher
Member since November 2005
Posts: 1,507
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Post by rallyrocks on Mar 2, 2007 14:11:05 GMT -5
Belts in question came from Kingsley North and Rio Grande, the fact that both mfg brands from both supply houses are giving me grief has me thinking it really has to be the drum, as that is the common denominator.
Just for fun I spun it without a belt and it does not appear- at least to the eye to do much expanding at all, so maybe its just stiffened up, I'll see if a good scrubbing loosens it up any.
I just noticed they are rated for use up to 2400 and I know I'm running closer to 1750 RPM, so going up a pully -or two even, might buy me some relief too.
And I do have another one to try out, I'll let y'all know what winds up working
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yogi
starting to spend too much on rocks
Member since March 2006
Posts: 175
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Post by yogi on Mar 2, 2007 18:22:25 GMT -5
Rallyrocks, increasing the speed would be a workaround, but the drums should be gripping the belts at like 500 rpm. It sounds like the rubber is stiff. Is your bench in a cold space? Could be just too cold. Might soak them in hot water. You could try some belt dressing to give the drum more grip, or some sort of rubber restorer. See what you can find at the auto parts store.
Bill
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rallyrocks
fully equipped rock polisher
Member since November 2005
Posts: 1,507
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Post by rallyrocks on Mar 2, 2007 19:50:14 GMT -5
At lunch I tried the next pulley up and that did certainly the trick.
But I will continue to look into some of the other suggestions, it has been rather cold, and the last couple of times I've fired up the rig I was using cold water (which not only keeps the rubber stiff, but it makes my fingers cold!).
So I'll fill up my water tray with warm water, adjust the drive pulley so its in line with #2 and I should be back at it tonight, hopefully....
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Post by rocklicker on Mar 3, 2007 0:42:24 GMT -5
Maybe you could put some veggie oil in the drum to soften it up more. I say veggie because petrolium based oils may degrade the rubber. Belts can sure vary in size too. I had a similar experience as Ed with tight Eastwind belts. I had to use a smaller expando drum.
Steve
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