I wanted to use the existing Lathe Estop position for the G540 electronics also,
but it is a Single Pole Single Throw Normally Closed switch. There are no contacts to connect the G540 Estop through. This would require a Double Pole Single Throw switch, but DPST NC switches are expensive and hard-to-find. Sure, I could use a relay, but that introduces a level of complexity and possible failure. IMO, an Estop needs to be simple and failsafe.
Fortunately, the normal $10 Estop switch that Keling sells has removable NC and NO contact modules:
It would be nice to be able to just buy an extra NC module, but I couldn't find any. Probably only for sale by the thousands anyway.
By combining the two Keling switches that I already have, a DPST switch can be made:
1) Carefully pry up the retaining clips and wiggle/slide off the green NO module:
2) Now do the same to the donor switch, only removing the red NC module.
3) Slightly trim the short dovetail on the red module so it will fit together with the other red one. Here illustrated on a green module:
4) Now slide the donor red module into the slots of the newly configured switch and snap them together:
Voila! a successful module transplant and a DPST Estop switch for cheap. Sponge please nurse:
5) Unplug the lathe, unscrew the front panel and turn the existing Estop knob counterclockwise until it clicks free. Remove existing Estop switch:
6) Extend it to the left, loosen terminal screws and slide off wiring (They are slotted terminals):
7) Install wiring onto new DPST Estop switch. It doesn't matter which wire goes where, as long as both wires are on just one module. I used the side closest to start switch:
8) Unscrew knob from new switch. (counterclockwise)
9) Unscrew chrome nut.
10) Install new switch thru hole from inside.
11) Attach chrome nut.
12) Screw mushroom knob back onto switch.
That's it boys and girls. There is now a red module just waiting for the Estop wire from G540 and then to PSU ground:
Waste not want not: The perfectly good old lathe Estop switch will now serve on another project--taking the place of the donor Keling switch.
And I now have a DPST NO Estop switch good for something if I can ever think of a use for it.
CR.