# My CNCs first bath.



## Pro4824 (Oct 17, 2015)

I "attempted" to mill a horse in a black granite tile. The Z was way off due to flex in the plastic tub but the horse test was just to confirm the machine could handle granite before going deeper into the rabbit hole. 🙂 
I've got a long way to go but you sure can't do that with a laser!! 😉

https://youtu.be/j00_463IIxc


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## RainMan 2.0 (May 6, 2014)

Wow , very cool !


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## difalkner (Jan 3, 2012)

What bit did you use, Joe? Sounds like your spindle is up pretty high, too. Did the water stay cool for the entire cut? Good job, btw!

David


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## old55 (Aug 11, 2013)

Nice.


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## sreilly (May 22, 2018)

I suspect that using a CNC system is a bit of a learning curve but you seem to have got it working well. Seeing and recognizing the issues as they happen goes a long way to getting the results you want/need. Looks like you're well on your way. Looks great to me Joe.


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## Pro4824 (Oct 17, 2015)

Thanks guys, until I get the kinks worked out, the granite milling is (for entertainment purposes only) 🙂

David, yep that's 24,000 rpm for the finishing pass with this bit.
Diamond 40 Degree PCD Cutter (3683) https://www.amazon.com/dp/B075BHLWBT/ref=cm_sw_r_cp_apa_i_TVKJCbWH3ZXAW

The roughing pass is 18,000 rpm with this bit.
Diamond Sintered Router Bits Straight Finger Burs for Granite Stone (C) https://www.amazon.com/dp/B07J1VYJJG/ref=cm_sw_r_cp_apa_i_VyLJCbKNBN4N4

Cutting submerged is my only option for now but from my research, everyone is using water cooling like this one so I'll be rigging it up soon. That way I can see what's going on instead of just looking at a tub of muddy water and wondering... 🙂

OriGlam Mist Coolant Lubrication Spray System https://www.amazon.com/dp/B071DXGGP4/ref=cm_sw_r_cp_apa_i_JeLJCbYHEHJJP

I saw a lot of feeds and speeds recommending 10-15 inches per minute so that's where I started but with the 6% stepover, that was gonna be about a 26 hour horse. 😞 and not worth doing. So I bumped everything way up to 12% stepover and 120 IPM
and finished the horse in 2.5 hrs. I think I can get it down to an hour without breaking anything but we'll see. 🙂


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## MEBCWD (Jan 14, 2012)

Joe looks good to me. Looks like you found reasonably priced bits to use and they did a good carve. The air-water cooling system you found looks like it would also help improve on the granite work. I think I would try to keep the stepover around 10% and mess with the other parameters to help keep a smooth 3D cut. You might also make a tray from plastic with a flat bottom to get rid of the flexing or make something to go into the tub that rests on the low portions and supports the work.

Joe thanks for posting this. Looks like you will push the limits of your new machine and then some. I look forward to seeing how far you can *PUSH* those limits.


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## OCEdesigns (Jan 31, 2019)

Looks grate to me! Thanks for posting this up. It shows that the limits to these CNC machines are only in our heads! I'm sure this gives people (including myself) ideas on other projects!
And thanks for posting up the links to the bits used. that is a big help also!


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## Scottart (Jan 8, 2015)

OK, that is a crazy water bath idea. That is mine stretching. thanks for posting.


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## marecat3 (Nov 30, 2010)

very cool but how did you hold it down?


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## Pro4824 (Oct 17, 2015)

Thanks, I have concrete board on the bottom of the water tray to hold the granite in place and clamps on the outside to keep the tray from moving X and Y. The Z is all up to gravity. 🙂


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