Robo3D Z Isolator v2 (with nylon nut)

Description

This design works a lot better as the surface of the nylon nut's washer face slips on the X carriage much better and the nylon nut has less slop on the threaded rod and less stiction. It helps remove Z ribbing caused by bent Z screws and/or Z couplers that aren't perfectly centered. Works best in tandem with a Z constraint like http://www.thingiverse.com/thing:1124184

Instructions

This design requires M8 Nylon Washer Faced nuts with a 13mm face to face distance. Such as the following ones on ebay.
http://www.ebay.com.au/itm/10x-M8-NYLON-NUTS-Metric-Washer-Faced-Stud-AUS-STOCK-/181226389121?hash=item2a31ef3e81:g:HqcAAOSwwbdWMqiv

Print 2 of these and press one of the nuts into each. Make sure the nut fits firmly and the guide arms don't have any slop on the 8mm Z guide rod but isn't tight. I lubricated the inside of the guide arms. Take your X carriage and Z nuts off and manually screw the isolators on, nut washer face up, onto the Z screws by turning the Z screw by hand until they're about an inch odd down on the Z guide rod. Do not try use the motor to do this as the Z screw will flop around and you could damage your Z coupler.

Once you have both isolators on and at the same height put the X carriage back on and control the motors to lower the carriage. You'll need to lower your Z end stop and lengthen the screw, if you have one. Re-level the bed and do a test print.

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