Hey Jace,
there are good locations all over the machine to attach ground wires (e.g. stepper motor screws. Don’t loosen adjustment screws on the machine though!). Usually ring connectors are used that are crimped to the the protective earth wires and that have a mounting hole to simply attach them on bolts. I don’t think it is necessary to make new holes, just use bolts that are already present.
It is important to order ring connectors with the correct combination of mounting hole (given by the bolt to which you want to attach the connector) and the wire cross-section area. The superior safety of a crimp connection can only be accomplished when both the sheet metal crimping sleeve of the connector and the crimping pliers insert are matching the wire cross-section area. Otherwise there is the danger of a faulty connection. The color code is: Red: 0.5–1 mm², Blue: 1.5–2.5 mm², Yellow: 4–6 mm². In the image above ring connectors for two wire cross-secton area ranges blue and yellow, and for three different bolt sizes, M4–M6, are shown.
(For conversion of IEC 60228 cross-section area to American Wire Gauge see here:
- Comparison of SWG (red), AWG (blue) and IEC 60228 (black) wire gauge sizes from 0.03 to 200 mm² to scale on a 1 mm grid – in the SVG file, hover over a size to highlight it)
The crimp insert shown above has two pressing surfaces one behind the other, the first to press the bare copper wires into the sheet metal sleeve, and a second behind that, which presses the entire wire together with its insulation into its own sleeve to create strain relief and kink protection. This allows to crimp both in one step. With simpler crimping pliers, you do this with two separate steps. The crimp pliers shown in the image above is rather expensive, but designed for day-long use, it features almost parallel crimping motion, consistently high crimping quality thanks to precision dies and ratchet mechanism (unlockable) and optimum transmission of force due to lever action for fatigue-reduced operation. Of course a $20 crimping pliers will also do:
However, there are also ring connectors without colored insulation and without bend protection. For this purpose, a different die is available:
However on those connectors, the same applies as said above regarding connector sleeve, crimp insert and wire size must match.
When retrofitting a serious cable sytem like drag chains, grounding all moving parts is easy.
All earth wires should be brought together in one single point.
Unfortunately I have not yet assembled my machine, otherwise I would show. I will show but I probably will first move to another place with a sufficient workshop before I assemble it.