I looked at you pictures. If you want a safe reliable machine you need to follow good wiring practices. Those open wires from the VFD to the spindle are antennas radiating RF over your whole neighborhood! Probably knocking out TV reception, interfering with wireless phones etc. Everyone hopes you'll give up on this machine so they can go back to what they were doing. Only half kidding here.
Your stepper motors also do the same kind of thing, they operate at pulse rates up in the Kilohertz range too. So you should be using shielded cables from the Gecko drives to each motor. You should use shielded cable from the VFD to the spindle motor too. The important thing is to create just one ground bar for ALL grounds, including the power cord ground. Do NOT jump a ground wire from one device to another and then to ground. Take ever ground from the device straight back to that one ground point. Important point here. For anything mounted to a grounded surface, that would be motors mounted to the frame of the machine, do NOT connect the shield from the cable to the motor, insulate it from touching ground at the motor. The other end of the shield should go to that one ground point. The frame should have one wire going to that ground point. For the spindle motor make sure the ground wire for the motor goes all the way back to that ground point. Do NOT connect the cable shield at the spindle. Insulate it from touching ground, tie the other end to only that one ground point. All the shielding so far is about keeping the noise from the motors, and drives from getting out.
You also want to keep noise from gettting in to signal wires. Use shielded wires here too. Connect the shield only to that one ground point. Do NOT connect any shields or grounds together to get back to the one ground point, always use a separate wire.
Where you have individual open wires always twist the RELATE wires together in a nice tight spiral up to as close to connection points as you can. This acts as shielding too. PLAN your wiring routes and neatly route signal wires away from power wired everywhere you possibly can. If they must cross, do so at right angles with as little wire near one another as possible. Never route signal and power in the same wireway if at all possible. If you can't avoid it, use only shielded wires.
"I'll neaten it up after I get it working" is WRONG!!! There is a strong possibility you will never get it working because it is sloppy and wrong. You also won't ever be able to make it neat because you already routed it wrong and the wires won't reach. You did OF COURSE make a wiring diagram BEFORE you started wiring, right? I'm guessing you aren't the kind of expert that can look at a mass of wires and see the wiring diagram in your head. So why would you try to do this without one? And just so you know I did wire my own machine without a wiring diagram! It was stupid even for me. However I have been building control panels for a little more than fifty years, so there is a pretty good chance I know how it work. You'll notice a pile of cut off wire ties as I work. That is because I tie everything down as I go. When I add more wires I cut out the first ties and replace them. My panels start out neat and stay that way right to the end as a result. I buy cheap ties to start and when I am done they are are high quality ones.
Got it?