drilling holes in hard stone

[duane roy]

Is it impossible to drill small holes in rock? I've been trying to use some local agate (or any rock that catchs my eye), on handles or leather hanging off case. I've tried regular drill bits fast/slow, tried carbide masonry bits fast/slow, neither one works. Usually the down pressure of the drill bits breaks the rock. There must be a secret?

 

[tom mayo]

you have to cut stones (drill in your case) with diamonds....they make all kinds of diamond drills......small to very large like in the concrete coring industry.....you need to run water on it...thats the main reason for cracking....heat....

 

[Cougar Allen]

Another way to drill stone is with a tube drill and loose grit. I don't think it's a good idea to drill stone scales, though; it'll end up weaker than if you just used epoxy without rivets or pins. Make deep gouges in the agate with a dremel, clean the heck out of both surfaces with solvent, and glue it up with JB Weld -- and don't clamp it too tight.

If you're totally paranoid about any possibility of the scales coming off blind pins would weaken the scales less. Or you could inlay the agate in metal; that would be the strongest way.

I'd worry more about the agate breaking than the epoxy failing, though. If an epoxy joint is done properly it's much stronger than agate. Cleanliness is vital to epoxy; most people don't clean the surfaces enough. I also like to heat-cure epoxy to make sure it hardens fully -- it doesn't need much heat; putting it near a light bulb will do it. You want it warm to the touch but not hot enough to burn you for a couple of hours after it appears to be fully hardened.

-Cougar Allen :{)

 

[Tom Carey]

The bits are not all that bad in price. I belive a small set of bits is about $40. from a major supplier. Yekim? I know you know the answer to that one.

Regards,


Tom Carey