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Advice milling stone

Tichy

Aluminum
Joined
Jan 1, 2019
A bit interested in milling some stone as afterwork hobby.

What about inserts? I have face mills / end mills available from Kennametal, Seco, Iscar, Sandvik, Alesa...

Can you use solid carbide or HSS at all? Is it all diamond where it's at?

Total newbie at this directions needed.
 
What kind of stone?

I assume carbide would cut most stones to some degree but any inclusions would spell quick death for carbide tooling.

Maybe look at some cheap diamond points from China or Amazon and see if you have any sort of success. I would not expect to get much done side milling or profiling.
 
I do lapidary work which is shaping various gemstones into decorative jewelry stones. Clear precious material, up to and including diamond, is faceted using diamond loaded laps. Semi-precious stones, such as agate, are ground into smooth shaped stones, generally using diamond loaded grinding wheels. Silicon carbide grinding wheels are sometime used. I would recommend milling stone by grinding, using diamond charged grinding tools. Things like grave stone markers and sculptures have been chiseled. Gutson Bolgrum used air powered impact tools and grinders in carving the stone at Mount Rushmore.
 
What kind of stone?

I assume carbide would cut most stones to some degree but any inclusions would spell quick death for carbide tooling.

Maybe look at some cheap diamond points from China or Amazon and see if you have any sort of success. I would not expect to get much done side milling or profiling.

Around 1953, I picked up some slate and white marble scraps from a new church building. Both stones machined OK with carbon steel tools and common Alox abrasive paper. Granite and quartz are a different game altogether.

There are some modern plastics for kitchen countertops that look like granite but machine like wood.

Larry
 
Totally depends on the stone. Anything hard like granite and nothing but diamond will cut it. Softer stones like marble, limestone and slate can be cut with carbide but it will disappear fast. How fast depends on the stone in hand since there is sooo much variation. Also depends on exactly how you want to "machine" it. Keep in mind the chips will be hell on anything that rubs together. Use enough water to keep the tool clean. When I tried carbide I used a router for fiberglass, don't bother with tools to cut metal as they are as far from what you want as possible.

This is my experience with machining stone, man-made quartz and ceramic. CGS
 
Granquartz.com or Regentstoneproducts.com
Both will have plenty of diamond tools. Stay away from any type of chip forming tool unless working with soapstone, marble.
 
Have a good shop vac on hand, I've tossed some garden type stones up before as favors to people for engraving or lettering and what a mess.
 
I turn soapstone, alabaster, and catlinite (pipestone) on my wood lathe. I use plain ol' HSS for tooling.
 
The only experience I have is with flattening old Arkansas stones with a face mill using carbide inserts. Yes it was messy but it worked quite well.
 
Diamond grinding wheels running wet cut through stone like it is not even there.

QT: [Can you use solid carbide or HSS] You might mill through some very soft stone with carbide..Good to wear a mask , would be very hard on the machine.
 
Interesting question; I was going to say go ahead as long as you don't use one of my milling machines. I really don't know though!
I learned how to make a sharp HS scribe out of a drill bit by drilling a hole in a AO grinder wheel with a drill press.
Dan
 
I used to bore the mounting hole of AO id wheels with using a carbide drill and on a drill press. The drill crushes the abrasive grit hard enough to break lose the bond. Drill goes dull but still continues to work.

Using diamond tip burrs to do lettering in stone I ruined a Dremel with the from the fine stone dust getting into the bearing.

If ever trying that again I would use a plastic bottle with a small hole for the burr shank to go through and so shielding the Dremel from the dust.

Stone dust is much finer that the grit that comes from using an AO grinding wheel. Grinding machine are designed to cope with abrasive by having way area shielded/ mills and lathes are not so abrasive dust gets into critical places quickly and is difficult to remove.

A 46 grit grinding wheel would have grit stone about .017" so less likely to get int tight places..stone grinding grit would be more like fine rouge powder..

OT: because of grit size it is near impossible to grind smaller than .02 radius corner no matter how many times you dress a 46 grit wheel.
 
I have two stage cartridge filtering on my coolant, 20 micron and 1 micron. A lot gets through the 20 micron filter so yes stone dust can be quite fine. If you don't feel safe dumping a few pounds of alox powder on your machine, adding enough water to make a slurry and then using it then you need more protection. Working with stone is hell on everything.
 








 
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