zsark72
noticing nice landscape pebbles
Member since November 2021
Posts: 80
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Post by zsark72 on Mar 14, 2022 18:29:16 GMT -5
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rockbrain
Cave Dweller 
Member since January 2022
Posts: 3,172
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Post by rockbrain on Mar 16, 2022 20:26:19 GMT -5
I'm sure you could do one by hand with enough work. I think that one was done on a lathe. Check this out Same thing, just slightly larger. |
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Post by rmf on Mar 17, 2022 6:53:10 GMT -5
The good news here is that you have chosen a soft material. I had a customer that wanted a gear shift knob out of Chevron Amethyst. What I learned was:
1. To drill the center hole set the whole piece in cement/epoxy to keep the stone secure while drilling. Rocks are very week in tension but very strong in compression. Until I did this the hole would split the rock. I just made a block of epoxy around my rock to drill the 1/2" center hole.
2. Polish the stone outside after the inside is completed.
My opinion is drill the center hole. fill with water then use diamond burs to grind the area out from the center hole. don't get too close to the wall, better to be too thick than to break through/crack.
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NDK
Cave Dweller
Member since January 2009
Posts: 9,440
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Post by NDK on Mar 18, 2022 19:25:11 GMT -5
Another option would be to drill the center out with a core drill, but then you'd need to add a piece to the bottom to cover the hole, or slice the bottom off before drilling then epoxy it back on afterwards.
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herb
spending too much on rocks
Member since November 2011
Posts: 475
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Post by herb on Mar 19, 2022 9:13:36 GMT -5
I dont know how these are done commercially, but I was thinking that using a core bit would work too. Maybe several bits of different diameters so you can break out some of the material. Kind if like when you make a bunch of kerf cuts on a piece of wood in order to make a notch or a half lap joint in the middle of it. Would run the risk of cracking it though
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oldschoolrocker
fully equipped rock polisher
Member since January 2019
Posts: 1,578
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Post by oldschoolrocker on Mar 19, 2022 21:40:42 GMT -5
I used diamond coated hole saw/ core bits on calcite and was easy peasy. Like herb said, I used diff size bits and broke out pieces then used diamond burrs to smooth it out. this is bit smaller than your pic but same idea regarding jole.   These are super cheap but work for soft material. More expensive bits surely will last longer but I did a few pieces of calcite as well as some rings from aventurine with these bits and they still have some life to them. |
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oldschoolrocker
fully equipped rock polisher
Member since January 2019
Posts: 1,578
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Post by oldschoolrocker on Mar 19, 2022 21:41:39 GMT -5
Oh and I just used a corded drill but drill press would work much better as well
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Cackling Chick
starting to spend too much on rocks
I LOVE ROCKS! 😁👍🏻🪨⛏️
Member since March 2022
Posts: 101
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Post by Cackling Chick on Apr 29, 2022 20:34:02 GMT -5
OMG, I love stone pots and bowls like that. Neat!
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