# Need recommendation for CNC bits that will cut through Carbon Graphite



## MageDK (Jan 27, 2021)

Hello all,

I am working on a project with a hobby CNC mill (Sainsmart 3018-prover) I've done a lot of good looking pieces in wood, but that is where my experience ends. I have basically used a variety of 2 flute straight edge bits and a few round end up cut bits but that's it. 

Now I am looking for some direction to be able to start carving Carbon graphite. I want to cut some molds in the graphite that I can use for casting metal. None of the bits that I currently have would be good for this.

I have done a few tests, in wood, of the mold I am trying to make. Here is the pic










Any recommendations on the type of bits I can use for this would be appreciated.

Thanks in advance


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## JOAT (Apr 9, 2010)

I would ask on a metal forum.


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## Pro4824 (Oct 17, 2015)

No need to find a metal forum, us CNC guys cut everything. 
I'd say your carbon graphite molds would be similar to hard granite which requires diamond PCD bits.
I use these from Amazon and they have worked great. You'll probably want to use lots of water to keep the bit cool and the dust contained and don't forget your Covid mask!!

*HUHAO 1PC 6mm CNC Router End Mill Diamond PCD Tools Stone Hard Granite Cutting Engraving Bits 40 Degree PCD Cutter (3683)*


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## Pro4824 (Oct 17, 2015)

Or maybe not, these guys don't seem to be using anything special. 




So, are you melting metal too? I just finished building my foundry furnace and did my first aluminum pour a couple of weeks ago. Bronze is next!


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## BalloonEngineer (Mar 27, 2009)

All those “corncob” burrs that sainsmart sells are for cutting PCB and other composite materials like carbon fiber. even though the carbon graphite does not have the fiber reinforcement, I imagine they would still work, but don’t know how smooth a surface they would leave. Those, or the bits you have been using will probably work, you will have to determine a new set of feeds and speeds. There is a “sainsmart genmitsu CNC“ group on Facebook, there are some pdf documents in the file section there that have lots of good info for those machines, including a feeds and speeds for all the sainsmart bits.


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## old55 (Aug 11, 2013)

Welcome to the forum @MageDK


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