The relays I used as “emergency stop” relays had some trouble with burned and sticky contacts. I replaced it with a bigger 40A relays but that also got the same problems (probably because of the inrush currents). Then I decided to make a solid-state relays with 4 TIP2955 transistors.
The circuit:
To drive this solid state relays and provide 12V for the fan in the back of the case I made a 12V power supply. On the cnc there will be led lighting, and that is also powered by this power supply.
Circuit:
The traces on the underside of the ssr are reinforced with wire so it can handle more current.
I also painted the top of the case.
Dutch 
