thomtap
starting to spend too much on rocks
Member since December 2007
Posts: 237
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Post by thomtap on Apr 2, 2009 17:47:09 GMT -5
I posted this in the home made equipment section but I haven't heard anything from it, so I thought this would be the next best place to post... here's my idea: I have an idea for a tool for small round cabs. It probably has already been done before, but most everything has! Anyway, the idea is this. A cone shaped grinding and polishing tool. If my uploading skills work, my rough image of the device will show better than my words will. The small end would fit into a chuck, or onto a shaft. Grit would be applied to the inside of the cone, and the stone would be worked around inside the cone to produce a good high dome. Polish would continue with another such tool for the polishing compound.
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MikeS
fully equipped rock polisher
Member since January 2009
Posts: 1,081
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Post by MikeS on Apr 2, 2009 18:38:41 GMT -5
interesting....what would you make it out of?
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agatemaggot
Cave Dweller
Member since August 2006
Posts: 2,195
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Post by agatemaggot on Apr 2, 2009 19:09:49 GMT -5
Saw some concave wheels on the Jadecarver web site that would do round top cabs perfectly. All you have to add is water. They sometimes go for $40.00 to $60.00 on his E-Bay auctions. I bought several wheels there at about $40.00 on average. Picked up a 6 in. 90 grit for $18.00 one time, These are all diamond I forgot to mention. If you keep your eye open there is often a treasure to be had there !
Harley
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agatemaggot
Cave Dweller
Member since August 2006
Posts: 2,195
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Post by agatemaggot on Apr 2, 2009 19:23:40 GMT -5
Never mind this week. just checked the Jadecarver store and it's all buy it now. concave wheels , some factory seconds are running $50.00 to $60.00 . 6" x 1" 120 to 600 grit Diamond. Not a bad price but a little short of a great bargain . Harley
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thomtap
starting to spend too much on rocks
Member since December 2007
Posts: 237
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Post by thomtap on Apr 2, 2009 20:13:20 GMT -5
Thanks Harley - I'll have to check them out. I would make the tool out of steel for grinding and wood or phenolic for polish. So far I haven't found any existing tools that I can use to do try this with. I guess it would have to be made expressly for this. Or, as Harley said, buy one of the diamond versions...
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onewomanarmy
has rocks in the head
Carpe Silicis!
Member since January 2007
Posts: 645
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Post by onewomanarmy on Apr 2, 2009 21:01:25 GMT -5
Interesting idea Thom because I was trying to come up with something almost the exact opposite! I'm trying to polish the inside edge of a cut bottle and having some trouble getting the results I like. I'm not very good with the dremel - or I'm not very patient with it - or a combination of the two. Anyway, what I was trying to come up with was an upside down cone with grit on the outside that I could bring the bottle down on top of to polish the inside lip. Was trying to figure out how to make something that might attach to a flat lap type grinder. Even wondered about using some of the Ameritool adhesive grinding/polishing discs. Since I only have access to a flat grinder was trying to figure out how to get a convex edge that would reach that inner edge. When you talk about making something Thom, I assume you are a machinist or have access to that kind of tools? If not, I'd love to hear what you are thinking as far as making something like this. Not that I wouldn't still like to hear how you do it even if you are going to machine it actually, I just won't be able to copy you at all. Cool idea though - seems like it would really help with uniformity. Please keep us posted on what you come up with!
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Post by Tonyterner on Apr 3, 2009 8:22:43 GMT -5
I'm far from the most learned person here but I would concerned that the grit would quickly wear away the steel altering its shape. Most of the rocks we work are harder than steel, 5.5 to 6.5 on the Mohs scale, and the grit is much harder than the steel, SC is around 9.
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thomtap
starting to spend too much on rocks
Member since December 2007
Posts: 237
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Post by thomtap on Apr 3, 2009 8:41:06 GMT -5
It would wear quickly. But eh wearing would produce a good figure of revolution, not a rough shape. In lens grinding, such tools are made of iron. (Old lens grinding techniques from the 40's to make lenses for eyepieces, etc.) But, if they could be made of steel, brass, copper etc. it wouldn't be expensive to make several I don't think. They could be "reconditioned" a few times.
I think this idea might be the basis for sphere making too.
Thom
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Post by Tonyterner on Apr 3, 2009 10:11:01 GMT -5
Its a good idea. Do you have access to a metal working shop?
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Saskrock
fully equipped rock polisher
Member since October 2007
Posts: 1,852
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Post by Saskrock on Apr 3, 2009 10:46:17 GMT -5
I'm sure I saw them using something like that to cab garnets in one of the cash and treasures shows
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thomtap
starting to spend too much on rocks
Member since December 2007
Posts: 237
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Post by thomtap on Apr 3, 2009 13:18:04 GMT -5
I used to be a machinist, but I haven't been in a machine shop in years. Don't have access to a lathe now. It would be a very simple tool to make though. Right now I'm looking for things to jerry-rig into one. I haven't found anything close yet.
Thom
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misguidedone
noticing nice landscape pebbles
Member since May 2007
Posts: 94
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Post by misguidedone on Apr 3, 2009 19:45:45 GMT -5
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drjo
fully equipped rock polisher
Honduran Opal & DIY Nut
Member since May 2008
Posts: 1,581
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Post by drjo on Apr 4, 2009 0:12:43 GMT -5
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Post by Tonyterner on Apr 4, 2009 8:45:45 GMT -5
Shame they couldn't be made out of aluminum or I could do them on my wood lathe.
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thomtap
starting to spend too much on rocks
Member since December 2007
Posts: 237
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Post by thomtap on Apr 4, 2009 9:22:12 GMT -5
Tony - you could do some of wood to try polishing round cabs! And Aluminum would work for two or three stones, maybe more before re shaping... you could try it out and see how it works!
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drjo
fully equipped rock polisher
Honduran Opal & DIY Nut
Member since May 2008
Posts: 1,581
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Post by drjo on Apr 4, 2009 9:52:43 GMT -5
Aluminum may color the stone, but wood will work, just make on for each grit and charge them.
Dr Joe
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drjo
fully equipped rock polisher
Honduran Opal & DIY Nut
Member since May 2008
Posts: 1,581
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Post by drjo on Apr 4, 2009 13:05:59 GMT -5
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