electricmonk
spending too much on rocks
Member since August 2011
Posts: 281
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Post by electricmonk on Dec 5, 2011 13:33:55 GMT -5
Anyone have an opinion on how difficult it would be to make a flat lap setup to use 8" or so magnetic diamond laps?
Based on the price of the few complete units I have seen it seems to me you could make one relatively easily/cheaply.
Aren't we talking about an arbor, steel (stainless?) platter and an enclosure that is waterproof and has a drain in it?
Anyone built one and have a source for a good platter? Could you mock one up out of plywood and and mount the arbor on a metal flange and just coat the thing in sealer of some sort?
Hmm...anyone have a used one for sale? ;D
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Post by jakesrocks on Dec 5, 2011 14:04:47 GMT -5
You have to first remember that you're not talking about just any arbor. You need an arbor that is designed to run vertically. Covington sells the arbors for $39.90 to $49.90, depending on your needs. You'll also need a motor which is designed to run vertically, such as an older washing machine motor. A stainless steel lap plate won't work. A magnet won't stick to stainless steel.
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electricmonk
spending too much on rocks
Member since August 2011
Posts: 281
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Post by electricmonk on Dec 5, 2011 14:12:18 GMT -5
You have to first remember that you're not talking about just any arbor. You need an arbor that is designed to run vertically. Covington sells the arbors for $39.90 to $49.90, depending on your needs. You'll also need a motor which is designed to run vertically, such as an older washing machine motor. A stainless steel lap plate won't work. A magnet won't stick to stainless steel. I KNEW THAT! ;D Not sure what I was thinking, lol Thanks for the thoughts, I see washing machine motors on Craigslist all the time, we are talking about the type that run the older "tub" style yes? As far as the arbor goes, that isn't too pricey assuming you can get the motor and some basic brackets cheaper. For that matter I am pretty sure that I remembered reading that some people have had success mounting a saw blade with the teeth removed to an aluminum plate to give the magnet a place to stick. I suppose you would have to seal it to prevent rusting...would prefer to find a steel lap plate that I could bolt to an arbor. Hmm...might just have to keep my eyes peeled on Ebay for a used flat lap in the size I want and just find a way to convert it to my purposes. Thanks!
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Post by jakesrocks on Dec 5, 2011 14:35:34 GMT -5
Motors for the older tub style washing machines will work. Most are only 1/4 HP, but if you can find a motor for a commercial machine, it should give you more power.
For your lap, you could always use a facetors aluminum master lap with a worn out lapidary blade epoxied to it. After using the lap, just remove your magnetic disc and dry the lap. then spray a little WD40 on it to prevent rusting.
You're going to need at least a 12" pulley on your arbor, and the smallest pulley you can find for the motor. Your lap wants to run at a fairly low speed.
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Deleted
Deleted Member
Member since January 1970
Posts: 0
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Post by Deleted on Dec 5, 2011 14:46:52 GMT -5
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Post by jakesrocks on Dec 5, 2011 16:16:18 GMT -5
There is in fact a difference in the bearings in a motor meant to be run vertically as opposed to horizontally. Suggest looking at pages 44 thru 46 of www.promshop.info/cataloguespdf/rolling.pdfMotors intended to be run vertically are designed with bearings which compensate for the thrust and weight of the armature pushing down against the the bearings. Motors designed for horizontal use don't use these special bearings. While a horizontal motor will run and work vertically, its life expectancy will be shortened.
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Post by johnjsgems on Dec 5, 2011 17:06:35 GMT -5
Don is right. I salvaged a few vertically mounted motors that had worn out the thrust washers until they would not start. They worked fine when I mounted them horizontally.
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Post by jakesrocks on Dec 5, 2011 17:55:39 GMT -5
It should also be pointed out that the special bearings in vertical mount motors can vary, depending on weather the shaft is to be mounted pointing up or down.
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Saskrock
fully equipped rock polisher
Member since October 2007
Posts: 1,852
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Post by Saskrock on Dec 5, 2011 19:52:57 GMT -5
Flat laps are super easy to build, talk nice to someone at you local heating/AC store and you can probably get a old furnace motor for free. At that price if you mount it vertical and the bearings go eventually who cares, just get another. Just make sure it is not a air over motor (fan blows air past motor). Here is a video of the one I built, it has done almost 1000 cabs now on the original free furnace motor. Its not magnetic but should give you some ideas. I'm sure you can improve on my design but it works.
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Deleted
Deleted Member
Member since January 1970
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Post by Deleted on Dec 5, 2011 23:42:24 GMT -5
Thank you saskrock Jim
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rockitman
freely admits to licking rocks
Member since September 2007
Posts: 771
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Post by rockitman on Jan 7, 2012 1:00:40 GMT -5
Monk. You are on the right track. But I say turn it up vertical! Most motors are made to run that way anyway. Like all the guys said above. Then you can get the horse power out of it. Also run as light a belt as possible as the bigger the belt the more vibration and noise. The diamond discs are cheap so you can keep fresh fast sharp discs at the ready. But you also will have all the worn ones that are so sweet. I do sapphires here on the east coast, and diamonds, start to finish are the only way. Crystalite still makes a 1/4 20 rubber flex disk that is great. Add the canvas and the diamond pastes and you are unlimited. Prepolish to polish. The magnetic disc is the trick though. Being able to swap disc in a few seconds is the ticket. They are great.
But! To make flat disc work so much easyier for cabbing. (Slow it down when its time to take the flat spots out.) A variable speed motor and control is the way to go.
Plus! Then it can be a polisher.
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sdgoldpanner
starting to spend too much on rocks
Member since January 2006
Posts: 226
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Post by sdgoldpanner on Jan 7, 2012 1:17:07 GMT -5
I have a solution for you on the vertical shaft setup. Most all older dryers have a hub on the back inside the case that holds a fan blade. Also included are three legs that connect the hub to the dryer. I have made several vertical shaft units and they all work great. The three legs work great for mounting it about 4" above the work table. I employ a 12" pulley on the unit and a 1" on the motor. The speed is just about perfect. I have another unit being used for making small spheres by hand. Just change the size of the pulley on the unit. If need be, I can take a pic in the morning of what the unit looks like. I could not be without my three units, all made from dryer hubs. Bob
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