What are the compact CNC milling machine options for stone carving

There are aluminum to copper wire nuts available, like Ideals 30-16. Basically it is a wire nut filled with NOLOX. It is made mostly for mobile homes that have aluminum wire and updating devices that might have failed or if you want to change the color, etc... They are not cheap, about over a couple of dollars each. You can but them on the internet or at mobile home repair shops.

Never use wire nuts that are rated copper only. If you do you are looking at a failure in the connection for sure.

EDIT - For larger cable (I just saw mains in your question) you can used al/cu rated split bolts. Use plenty of NOLOX then wrap in rubber tape and then a good electricians tape, not the cheap black tape.

Do not use the copper split bolts, they are rated copper only. Make sure the connector shows al/cu ratings on it.

These are used to tie rebar wire around rebars - twisting the wire around the rebars, and then cutting the left over. Rebars are used prior to pouring the concrete to strengthen the concrete, hence the tool name.

They are also called "end-nippers", and are useful for cutting or grabbing things close to the surface, such as nails or the like. Finally, they can be used to cut tiles, however I have no experience with this function and can't comment on it.

See this nice little PDF that shows a picture of the two uses of this tool (no affiliation, just what Google came up with).