rattlehead
starting to spend too much on rocks
MI Rocks
Member since December 2010
Posts: 213
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Post by rattlehead on Jul 25, 2015 8:30:21 GMT -5
I have to drill a hole through a roughly 5 inch deep Petoskey stone. I would prefer a 1/4" hole but I could do a 1/2" also. I have not been able to find any drill bits of that size/length. The smallest core bit I found was 3/4" (plus I don't have a working core drill at the moment!). Would another type of drill bit work on a Petoskey if I kept it wet/cool? Any suggestions?
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Post by Jugglerguy on Jul 25, 2015 9:10:26 GMT -5
I have no experience with drilling that far through Petoskey, but wouldn't a masonry bit work? Petoskey can't be that much harder than concrete. Maybe you could start the hole with a lapidary bit so it's a clean cut, then continue with a masonry bit. If this is for your pendulum, I'd experiment on something else first.
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rattlehead
starting to spend too much on rocks
MI Rocks
Member since December 2010
Posts: 213
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Post by rattlehead on Jul 25, 2015 9:41:22 GMT -5
A masonry bit would work, I just can't find one in the size I need.
It is for the petoskey core. They need the hole through it now. I'm also worried about it breaking if I put the hole through it.
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panamark
fully equipped rock polisher
Member since September 2012
Posts: 1,343
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Post by panamark on Jul 25, 2015 9:45:32 GMT -5
Petoskey is quite soft. After you get a hole started, couldn't you: get a 1/4" piece of copper (solid or pipe) and partially fill the started hole with coarse grit SilCarbide. Then add a bit of water to make a nice slurry and drill away with the copper. The copper will "grip" the SiC and I think you will go pretty fast.
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quartz
Cave Dweller
breakin' rocks in the hot sun
Member since February 2010
Posts: 3,339
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Post by quartz on Jul 26, 2015 0:15:50 GMT -5
Agree w/ panamark, I've done some holes w/copper tubing in quartz, one ~5" long; slow but effective. Copper work hardens with use, helps extend the life of the tubing. Keep the tubing snubbed up as short as possible so it will have less tendency to bend. Lots of "pecking" rather than just trying to plow thru, always wet and keep some grit in it.
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rattlehead
starting to spend too much on rocks
MI Rocks
Member since December 2010
Posts: 213
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Post by rattlehead on Jul 26, 2015 7:19:58 GMT -5
Thanks! I'll give the copper a try! I appreciate the tips!
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Post by orrum on Jul 26, 2015 7:37:26 GMT -5
Wow I tried drilling rose quartz with a masonary bit and the quartz laughed at me. Now I find out a soft copper pipe and sc grit will cut thru quartz. Maybe humans really did build the pyramids! There goes the alien theory down the tubes! LOL. Awh shucks I am gonna stick with the aliens!
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Post by johnjsgems on Jul 26, 2015 15:06:57 GMT -5
I've drilled marble with masonry bits so should eat right through Petosky. We had an old guy that drilled lots of holes for members at our club workshop. He made a dam around the hole with Play Dough and used whatever size tubing needed in a drill press. Ink pen refills for smallest sizes and tubing for everything else. Very slow going through hard rock but should sail through soft stones.
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Post by jakesrocks on Jul 26, 2015 21:11:50 GMT -5
I'd think that masonry bits might chatter too much, and cause the rock to shatter. Unless of course it were a large rock, and the hole was well away from the edge of the stone.
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Deleted
Deleted Member
Member since January 1970
Posts: 0
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Post by Deleted on Jul 27, 2015 6:50:11 GMT -5
This place has core drills from 1/8" to 1.5" by 1/16" steps all the way up. To go deeper you can get a 1/4" drill extender at most hdwr stores that would make it possible to drill 6" +. When you reach the depth of the core drill you would have to break off the core and start again. You would need a core drill with a 1/4' stem or you could drill out the extender to 5/16". They also have a lot of drilling information that is very useful. Not sure about this place but I know there are places that will make up just about any size and length you need. Jim www.ukam.com/core_drills.htm
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