Milling Stone/Masonry?

[James@fireaxe]

Any one venture into milling/engraving into Stone or Masonry? A little research suggested to use diamond grinding bits and to not plunge but to slowly ramp into the material with ample water for cooling. 

Anyone have any experience with this?

[mirthmgr]

I've done a bit of stone milling, but not a ton. A lot is going to depend on the particular stone you want to mill, as they vary in hardness a lot. I've had some success with labradorite and marble. Marble is about as soft as stone gets, and you can buy tiles of it from a big box store pretty darned cheap (I think I got a pack of 10 3"x6" tiles for around $8), so it's a pretty good one to start with.

I've used a combination of burr mills and v-bits for marble. These are the types of burr mills I'm using: www.amazon.com/gp/product/B073TXGGKX/ - there are probably better options, but those are cheap and seem to be doing the trick. Marble is fairly brittle, so I found (thanks to aforww's advice) that running a trace operation along my contour and pocket paths with a v-bit at a very small depth (.1mm or so) will create a clean line, and then any pocket and contour operations don't chip the surface.

I have not used any water to cool my cuts, but I think harder stones would require it. Here are the threads from my experiments:
millrightcnc.proboards.com/thread/738/test-stone
millrightcnc.proboards.com/thread/761/adventures-marble


Good luck! Please post the results of any experimenting you do!

[James@fireaxe]

Thanks I will try a few experiments and post them here.

[James@fireaxe]

So I tried engraving on a brick. This brick came from a Houston Fire Station 67 that torn down and was rebuilt. A buddy wanted me to engrave the station number on it.

I used a flat end diamond coated grinding bit. It worked ok for the first number, the #7. It wasn't a very expensive bit, so I think the diamond coating wore off quickly as the quality of the engraving was reduced in the 6 and the s. The brick was a lot harder than anticipated. I tested on another brick and I wasn't as hard. I went slow about 200mm per min, used ramping profile entry, with little squirts of water while it was grinding.

After some further research, 2Linc sells bits that they say can engrave in granite and armor steel. I'll try one of those bits on a piece of scrap granite I can find. Il report back when I get that done.

James

[Bruce]

Looks like it came out pretty good. Experience is the best teacher. You'll be the expert in no time at all.

[friolator]

Not to be a downer, but be really careful while you do this. The dust from quite a few variety of stones (including concrete and I think brick) is known to cause silicosis. Granite is one. You really want to be wearing a respirator. en.wikipedia.org/wiki/Silicosis

Soapstone might be an interesting one to try - we used it for our kitchen counters and it's super easy to cut using carbide tipped blades and drill bits. But again - the dust is super bad for you, so you want a good dust removal/filter system, a respirator and some water to keep it from becoming airborne.

My understanding is that there's little to no silica in marble, so it's much safer to carve.

(one of my first days in art school they sat us in an auditorium and told us all the ways we could die - exploding acetylene tanks, silicosis, cancer from encaustic paint techniques or photo chemicals, etc).

[James@fireaxe]

Great info definitely. I had my dust boot on when I was cutting it.