Lest the newbies on the forum think that those of us who have been doing this for a long time never run into any problems....
Not every experiment will be a success
In the past I've cut limestone, soapstone, and marble. In fact, our first paying job was carving a pair of pheasants into a limestone fireplace mantle. Indiana Limestone is about 2.5 on the Mohs hardness scale. Marble is around 3-5 on the Mohs scale. You can carve it with a Porter-Cable router and a carbide V-bit with only air cooling.
A few weeks back I saw someone giving away free "limestone" pavers. I picked up about a dozen pieces about 12-24 inches per side and about 1.75" thick.
I put one on the table today and tried a very slow, shallow (0.001") cut. As soon as I started seeing sparks under the dust foot I knew to shut it down immediately.
It seems that what my neighbor thought was limestone actually has quartz/quartzite in it -- 7 to 8 on the Mohs scale.
Lesson learned: Get the material from a stone distributor who actually knows what they have.
Well, I now know a process for inlaying solid carbide into quartz "limestone".
This is what it does to solid carbide.
When "Limestone" contains Quartz
- Rcnewcomb
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When "Limestone" contains Quartz
- Randall Newcomb
10 fingers in, 10 fingers out, another good day in the shop
10 fingers in, 10 fingers out, another good day in the shop
- dhellew2
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Re: When "Limestone" contains Quartz
Solid carbide bits do a great job of cutting thru metal hold down clamps Dale
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Re: When "Limestone" contains Quartz
Been there, done that.
Gary
Gary
- newmexico
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Re: When "Limestone" contains Quartz
Ditto on that!
- scottp55
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Re: When "Limestone" contains Quartz
Thanks for posting Randall!
Yep, pretty easy to test a piece like the Slate in pic with a penny scratch test, and to see the quartz intrusion and stay AWAY from it.
But when the quartz is mixed in homogeneously...VERY difficult!
Have some Italian Marble I've thought about, but keep putting off because white streaks need more hardness inspection(low priority:)
scott
Yep, pretty easy to test a piece like the Slate in pic with a penny scratch test, and to see the quartz intrusion and stay AWAY from it.
But when the quartz is mixed in homogeneously...VERY difficult!
Have some Italian Marble I've thought about, but keep putting off because white streaks need more hardness inspection(low priority:)
scott
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Re: When "Limestone" contains Quartz
"Solid carbide bits do a great job of cutting thru metal hold down clamps" You must use a better grade of bits than I use, mine always snap right off! LOL Russ
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- Rcnewcomb
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Re: When "Limestone" contains Quartz
So far I've avoided that. I was impressed that one of my Rockler hold down clamps actually stopped my gantry when I had the clamp overhanging the table.Solid carbide bits do a great job of cutting thru metal hold down clamps
- Randall Newcomb
10 fingers in, 10 fingers out, another good day in the shop
10 fingers in, 10 fingers out, another good day in the shop