Stoney CNC do sell them - https://www.stoneycnc.com/cnc-compon...ooling-systems

I made one for my old Novamill. They aren't complicated, and the key is in the pressurised coolant source and the mixer.

Just done a quick search, and these are the plans I roughly followed - https://www.cnczone.com/forums/uncat...nt-mister.html
And this was the coolant I used - https://www.johnnealeltd.co.uk/shopenvirocutse10.html