Need Help! Gerber System 48 Build Issues Video and Pictures Inside!

[JAZZCNC]

Most of your trouble is coming from the poor mechanical setup of the machine. The Motor for instance on the Gantry being fastend with just 2 bolts and washers will have massive affect on how they work. The poor fastening means Resonance will cripple them and cause issues just like what you are having.
The fact you have Cheap Analog drives means they won't be able to deal with the Resonance so you get these kinds of issues. You'll often hear this called Mid band resonance but cheaper drives can suffer badly at lower speeds.

Funnly enough I just had machine which was using Cheap analog drives and it was giving issues similair but not any where near as bad, mostly because the motors where fastend correctly and much better made machine. But still the same horrible noises and resonance affecting motors while cutting. To the untrained ear you'd swear it was a mechanical issue. When infact it was Resonance affecting the drives which couldn't deal with it and cancle it out.

Just changing the Drives for Digital drives cured the problem and doubled the speed. It was night and day which was instantly noticable by audible change from the motors. Difference is comparable to 6 cyclinder engine running on only 2 cyl.!!

In your case I suggest you make a much better job of the mechanical setup and then play with Micro stepping to move the resonance to differant range.
With a little playing about you may hit a frequency the drives will work in.

I also Notice the High steps Per setting so I'm presuming you are using Imperial Units not Metric.? . . . If not then your probably completely setup wrong.