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Post by captbob on Nov 23, 2015 11:29:46 GMT -5
Thank you for posting the follow up.
Some may not be exactly round, yet some look perfect. Do you think that if given more time the not quite round ones would round up better - just smaller?
If allowed a favorite, I pick the 2nd down from the top on the left side.
What are these (maybe you already said) and do you think different hardness stones would round differently or easier?
Whatcha gonna do with them?
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Post by cobbledstones on Nov 23, 2015 19:20:08 GMT -5
captbob, I think they would get better (and smaller) with time, and perhaps patience is king, much like tumbling. I have a 2nd batch planed with a little nicer materials, for those I will roll them as long as I dare and see what happens. The materials in this batch is a mixed bag: some local agate (the white stuff); some of the leftover Rios from mel (I highgraded his batch and took the best for a bead making project, there is a link of that somewhere) and an unknown moss agate from the bargain bin of my local rock shop (your fav). I picked them because they were all roughly the same hardness and I had chunky bits already cut. Dearest wife claimed them for decoration. She wants to put them in some of her antique glassware. This is surprising, she normally doesn't like rocks in the house. means they have more decorative appeal than other stuff I made 
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jamesp
Cave Dweller 
Member since October 2012
Posts: 36,606
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Post by jamesp on Nov 26, 2015 11:02:32 GMT -5
Amazing stuff. Thought stimulating, this process. Thinking about an 8 footer for doing bowling ball sizes...??
I have been pondering a bowl tilted and spinning fairly fast. With those new fan dangled diamond impregnated segment brazed to the bottom.
A standing and rolling wave of rocks trying to climb the tilt but in a roll abrading against the bottom of the diamond coated bowl spinning rapidly.
Basically a coarse grind tumbler that may tend to make round balls.
Thoughts ??
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Post by cobbledstones on Nov 27, 2015 0:14:14 GMT -5
Always thinking, it get me in trouble. I think that an oversized marble mill would work. could repurpose an old millstone for the process maybe. I like the idea of your device. The most time consuming step in the whole process is the initial rough out...going from cubes to near spheres. If that could be automated, the whole process could be automated.
I once saw a video of a machine that had a steel barrel with a very shallow paddle on the bottom that rotated rapidly. this nocked the corners off stone cubes so they were round enough to go into the mill.
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jamesp
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Member since October 2012
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Post by jamesp on Nov 27, 2015 5:54:45 GMT -5
These are blocks of sintered diamond. They are for brazing onto 6=8-10-12 foot diameter quarry saw blades. So made for harsh duty. They average 3/8" thick, which is the kerf of one of those large quarry blades. If you could completely cover the inside of a rotating tumbler barrel or inclined bowl with them and get the angle/slurry correct some serious hands off grinding may occur. I bought a 4" X 4" X 3" box of these on Alibaba for $50. I think it had 80 segments about 3/8" X 1" X 3/4". That is probably more diamond than 3-4 cab machines has on all it's wheels combined. Just saying, they are relatively cheap. They are attached to steel by brazing, so you would have 3/8" solid diamond sintering, a lot.  Looking at the action in this mixer, except the diamond segments welded to the barrel entirely coating it. Perhaps a smaller scale, a slurry, and increase the slip against the bowl for increased abrasion by increasing the speed. |
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Deleted
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Post by Deleted on Nov 27, 2015 8:22:28 GMT -5
Why are they tumbling lead shot?
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jamesp
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Post by jamesp on Nov 28, 2015 6:29:06 GMT -5
Why are they tumbling lead shot? Good question. Curious if they had a flat mold with a lot of pockets and spread molten lead across it. Harvested the roughly molded castings and the tumbled them to round them. That type of tumbling should be good at rounding the material. Seems like you would need grit though, or maybe the lead is so soft it gets shaped to round. Like rolling against the hard steel bowl beats it into round shapes. It is heavy. Ah, this is how they make the shot, then they must tumble it to get it round Apparently they tumble all home made shot. |
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Deleted
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Post by Deleted on Nov 28, 2015 7:05:49 GMT -5
Ahah.you sure you weren't some kind of investigator,damn your a trove
Dave
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,606
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Post by jamesp on Nov 28, 2015 21:49:58 GMT -5
Ahah.you sure you weren't some kind of investigator,damn your a trove Dave Thinking about a dripping lead shower. |
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Deleted
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Post by Deleted on Nov 29, 2015 6:07:42 GMT -5
Nice
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Post by cobbledstones on Dec 6, 2015 22:18:02 GMT -5
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Post by toiv0 on Dec 7, 2015 20:50:07 GMT -5
One of the sweetest threads I have read. Has a guy thinking. Great job!
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SirRoxalot
freely admits to licking rocks
Member since October 2003
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Post by SirRoxalot on Jan 26, 2016 12:29:11 GMT -5
I love this. Beautiful, beautiful work. Methinks an old flatlap could be turned into a sphere mill pretty darned easily. And I happen to have a nice heavy old flat lap, hrmmmmm...
Thanks for sharing!!!
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