Anyone ever cut Limestone?

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SuperDave
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Anyone ever cut Limestone?

Post by SuperDave »

I have a request to cut some Limestone Fireplace Trim using .STL files. I have a Techno Isel 4896 Plus Servo Router with an HSD 3HP Spindle. However, I have not found any information where someone with a non-stone router has milled Limestone. My milling time on the sample file is already approaching 14 hours for one 8.5' c 7" strip and the settings I used are nothing but a WAG... most likely too fast for the material and my setup.
  • I have been told that Limestone is "soft" which might be a relative term...
    I have been told it can be done, using Carbide (which I use almost exclusively).
    I don't have any idea about speeds and feeds and I would have to cut it dry.
I am supposed to get a sample to test, but I would like to get a head start on the preferred settings before putting my router through any unnecessary stress for a project I might find unsuitable for my machine.

Any help or insights would be appreciated.

SD
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ssflyer
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Re: Anyone ever cut Limestone?

Post by ssflyer »

I've cut several pieces of limestone, and the material I had actually cut great. I'm not at my design computer, so don't have the speeds/feeds handy. I'll look for them later, but they probably won't be that much help as I've only V-Carved it - no 3d work.

The v-bit cut great, but I'd probably be worried about heat on a long running job like you have. On the other hand, on one job it was cutting about 3/8" deep, without issue...

Hopefully someone on the forum has some more information on this.
Ron Sloan

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SuperDave
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Re: Anyone ever cut Limestone?

Post by SuperDave »

Ron,

Well, that's encouraging. I was initially setting it for 100-150 IPM with about 48% step over on roughing with a .25" Ball Nose @ .0625 depth, and 15% on finishing with a .125" Ball Nose.

SD
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Re: Anyone ever cut Limestone?

Post by Rcnewcomb »

I've cut it before using a ShopBot PRT Alpha with a 3.25HP Porter Cable router. It carves nicely for shallow V carving and does well for 3D work.
Image Image


Your feed rates are about the same as I used. The only spot where I would run into trouble was the final cutout with an end mill. You want to do lots of very shallow passes (0.100" or less per pass at 60 IPM) My stone wholesaler could cut it to size with less risk than I could so it was easier for me to do the carving and he did the cutting.

BTW Those settings should work for marble or soapstone as well.

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Re: Anyone ever cut Limestone?

Post by Rcnewcomb »

15% on finishing with a .125" Ball Nose
I wouldn't go any higher than a 10% stepover, but you can move very fast with the 3D finish pass because you are only removing 0.0125" material per pass (10% stepover with a 0.125" bit), so the load on the bit is quite light. I would run with 300-360 IPM on the XY and 180IPM on the Z. Of course it would never really reach those speeds because of ramping.

Depending on your design you may be able to just run part of the roughing pass to keep your finish bit from diving full depth at the start of the cut.
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Re: Anyone ever cut Limestone?

Post by Khalid »

I have cut marble on my MDF made CNC router. I used normal HSS tools used for wood with drops of water as coolant. a brief video:
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Re: Anyone ever cut Limestone?

Post by Jimi »

Hi Dave just saw your post I have been given a similar job I know this was a while back but would you still remember the speeds and feeds and did you need to use water at all? cheers Jimi

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Re: Anyone ever cut Limestone?

Post by Rcnewcomb »

I give my feeds and speeds on this thread: Limestone Seahorse

Don't use water or you end up with a cement slurry all over your machine. :shock:
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Re: Anyone ever cut Limestone?

Post by Jim_in_PA »

I will add this...you need to be really good about dust control with this application. Aside from the "mess" and personal health concerns, that stone dust is abrasive and it can "do a number" on things like your spindle, etc. Take great care with this. That said...kewel project!

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Re: Anyone ever cut Limestone?

Post by phill05 »

Hi SD,

Yes it is a very nice stone to cut but you need floods of water to get the best out of it, carbide is the tool to use I grind my own 3 face cutters and the finish is very good.
Image
For some reason insert image is not working for me.

Phill
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Re: Anyone ever cut Limestone?

Post by phill05 »

There you go working now:
Head.jpg
Fireplace.jpg
Phill
A person who works with his hands, his brain and his heart is an artist"
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