# Cutting lava rock on the mini cnc?

**URL:** <https://discourse.southlondonmakerspace.org/t/cutting-lava-rock-on-the-mini-cnc/36279>\
**Category:** Discussion\
**Tags:** cnc\
**Created:** [30 August 2024 00:37 UTC](https://discourse.southlondonmakerspace.org/t/cutting-lava-rock-on-the-mini-cnc/36279 "2024-08-30T00:37:36Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![carb](https://discourse.southlondonmakerspace.org/user_avatar/discourse.southlondonmakerspace.org/carb/32/14574_2.png) [@carb](https://discourse.southlondonmakerspace.org/u/carb)\
**Post date:** [30 August 2024 00:37 UTC](https://discourse.southlondonmakerspace.org/t/cutting-lava-rock-on-the-mini-cnc/36279/1 "2024-08-30T00:37:36Z")

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Generally cutting rock requires special bits and cooling and obviously we don’t have cooling on the Mini, but would it be ok for me to attempt to cnc some notches into some lava rock dry (with bits i buy)? (This would be for turning small rocks into table number holders for an event by adding a slit.)

Online someone said they had success using feeds and speeds from an old shapeoko wiki: [https://public.tableau.com/app/profile/willadams/viz/CNCFeedsandSpeeds/Sheet1](https://public.tableau.com/app/profile/willadams/viz/CNCFeedsandSpeeds/Sheet1)

At first glance the settings for a three flute carbide bit look achievable on the Mini (1000mm feed rate, 15k rpm), but idk about the torque of the motor.

(same question for the big cnc re: viability)

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**Author:** ![asander1](https://discourse.southlondonmakerspace.org/user_avatar/discourse.southlondonmakerspace.org/asander1/32/14251_2.png) [@asander1](https://discourse.southlondonmakerspace.org/u/asander1)\
**Post date:** [30 August 2024 01:01 UTC](https://discourse.southlondonmakerspace.org/t/cutting-lava-rock-on-the-mini-cnc/36279/2 "2024-08-30T01:01:57Z")

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[@CNCtechs](https://discourse.southlondonmakerspace.org/groups/cnctechs)

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**Author:** ![Christian](https://discourse.southlondonmakerspace.org/user_avatar/discourse.southlondonmakerspace.org/christian/32/11983_2.png) [@Christian](https://discourse.southlondonmakerspace.org/u/Christian)\
**Post date:** [30 August 2024 07:11 UTC](https://discourse.southlondonmakerspace.org/t/cutting-lava-rock-on-the-mini-cnc/36279/3 "2024-08-30T07:11:53Z")

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To my knowledge we’re not permitting to mill stones and hard metals\* on any of our cnc machines.

There is the cooling issue that usually requires liquid coolants, the chip type / dust and higher torque needed than our spindles provide.

While in your case torque is probably not a problem, the liquid cooling to bind dust prevails.

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**Author:** ![carb](https://discourse.southlondonmakerspace.org/user_avatar/discourse.southlondonmakerspace.org/carb/32/14574_2.png) [@carb](https://discourse.southlondonmakerspace.org/u/carb)\
**Post date:** [30 August 2024 08:58 UTC](https://discourse.southlondonmakerspace.org/t/cutting-lava-rock-on-the-mini-cnc/36279/4 "2024-08-30T08:58:39Z")

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Ah i didnt think about the cooling service s secondary purpose of binding the dust. I’ll let my wife know. Thanks!

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**Author:** ![dannz](https://discourse.southlondonmakerspace.org/user_avatar/discourse.southlondonmakerspace.org/dannz/32/16868_2.png) [@dannz](https://discourse.southlondonmakerspace.org/u/dannz)\
**Post date:** [30 August 2024 09:53 UTC](https://discourse.southlondonmakerspace.org/t/cutting-lava-rock-on-the-mini-cnc/36279/5 "2024-08-30T09:53:34Z")

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Also, as I understand it from Joe, stone dust is terrible for machines and so that should be avoided in the space. Cutting outside is an option e.g. using the dremmel. With a circular saw attachment with diamond blade you might be able to do what you want with that, though doing by hand rather than CNC.