Prints randomly turn out bumpy with weird skips on contour

[MakerDude]

It is a little hard to describe what is happening other than randomly the prints will have a layer (or multiple layers!) that will not be consistent with their previous ones, and I know this is not a slicing related issue as the model looks smooth in the slicer. I am not sure if there is any "slip/stick" in the delta arms ball joints and is causing this or if this is related to something TOTALLY different. The other issue is that it will occur randomly, so one print will go fine... next one... not as well. Hopefully the images will help explain this phenomenon!

https://goo.gl/photos/Cy1wfprwJNinhEvp7
https://goo.gl/photos/tzPoWSVfYiXysXtG9

Here are the settings:
Model sliced in Cura
RostockV2 with E3DV6 hot end with .8 nozzle
.72 layers
printed in Taulman T-glase
15MM/S print speed
240C nozzle

Thanks
Maker Dude

[Qdeathstar]

I think you want your layer height to be no more than half your nozzle width, so that is .4mm instead of .72

[MakerDude]

To keep the prints as clear as possible I am running them at the high layer height, T-glase lets you do that... although the print speed has to be lower.

[Nylocke]

You really shouldn't go above like 3/4's of your nozzle diameter with your layer height. Try with .5 to .6 max, I know that you're supposed to go high with T-glase but you might be a bit too high. Are you using the stock V6 heater block or a Volcano? I think you might have better luck with a Volcano. Is this one perimeter no infill? I think the best results are supposed to be with no infill 1 perimeter.

It looks like you have decent layer alignment so I think the issue you're having is maybe torque stalling the stepper or something similar. Cura should tell you the flow rate you're running at if you hover over the speed boxes, but I think you're going a bit too fast for a V6 heater block if thats what you're using.