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  1. #1
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    Drilling Obsidian?

    I need to drill two blind holes in the backs of two Snowflake Obsidian cabochons. Any ideas what drill bit to use and how to keep them flat when drilling?
    Jim

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    You say that I drink too much, to me thats profound, how do you know you can't swim untill you have drowned?

  2. #2
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    Re: Drilling Obsidian?

    A ceramic tile bit should do the trick, nice and slowly does it though.

    If you hold the material in a piece of old leather you should be able to use a vice or set of grips to hold it flat and steady.
    Carpe cerevisi

  3. #3
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    Re: Drilling Obsidian?

    No direct personal experience but I remember being told it behaved like glass...
    Well, everybody in Casablanca has problems. Yours may work out.


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    Re: Drilling Obsidian?

    I never thought of grips! I have a set of locking pipe grips that would do the job, thanks for that. Can you get 2mm ceramic bits?
    Jim

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    You say that I drink too much, to me thats profound, how do you know you can't swim untill you have drowned?

  5. #5
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    Re: Drilling Obsidian?

    It's just black glass (probably with improper annealing, stress and micro fractures).

    I'd set it in resin, clamp and drill with a diamond bit and a lot of water, and with low thrust and low speed.

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    Re: Drilling Obsidian?

    You can get 2mm diamond bits, but gentle and slow goes double for coated helical twist drill bits.

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    Re: Drilling Obsidian?

    This idea might not be worth all the trouble.
    The holes just need to be deep enough to line up accurately over pins and add a bit of strength to the epoxy.
    I might just try a dremmel bit to just put a dint in them!
    Jim

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    You say that I drink too much, to me thats profound, how do you know you can't swim untill you have drowned?

  8. #8
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    Re: Drilling Obsidian?

    Again, diamond dremel bit at low speed with water....

    Anything faster will just blunt or wear out whatever you're using.

  9. #9
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    Re: Drilling Obsidian?

    B&Q do tile/glass drill bits down to 3mm,
    with a diamond cutting disc for a dremel, you can easily grind it down to 2mm

  10. #10
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    Re: Drilling Obsidian?

    Have managed to rough up the backs, so will just rely on the strength of the epoxy. Saves a lot of faffing about!
    Jim

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    You say that I drink too much, to me thats profound, how do you know you can't swim untill you have drowned?

  11. #11
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    Re: Drilling Obsidian?

    I use diamond bits and I have one dremel set up as a drill press. I use a bead of dopping wax where I start my hole and use dopping wax on the backside to attach it to a small wood block. This also helps prevent chipping/cracking when the diamond bit exits the obsidian. The block is weighted with some lead so it won't float. I put the wood and obsidian in an acryllic bowl filled with water so that debris will float away. I also remove the obsidian from the water a few times to flush out the hole I'm creating with a small squirt bottle. (this helps clear the hole of diamond and obsidian debris so that diamond bit does not dull by drilling on diamond debris). The bits will last much longer using this method.

    I go slow and drill the obsidian while it's in the water - keeps it cool. I get the dopping wax at a lapidary supply store online.

 

 

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