Quote Originally Posted by RobH2 View Post
I also see a new connection method for the Z Rods to the stepper motors. Is that a standard part for the i3v or a mod? I find that my rubber connections are prone to slipping. They do provide some protection in a head crash as they will release and push off, but as even the lightest lubrication eventually makes its way to the bottom, it discolors in the vinyl tubes, so I know it's there. They aren't as tight as they used to be.
I replaced the vinyl tubing with aluminum Z couplers for the reasons you mentioned. Oil was getting down into the tubes and I figured it would eventually cause a problem. Also, the tubes don't really center the threaded rod up very well, so the Z rods wobble when printing.

The coupler is designed to allow the shaft to flex as it rotates, but it also essentially suspends the weight of the X assembly on an aluminum spring, and it rings as the Z axis turns. They're really designed to be used with ball screws that have thrust bearings in the mounts. I went ahead and slid the threaded rods all the way down so they actually contact the motor shaft, and this stopped the ringing noises.

I'm not worried about a crash, because the nuts will ultimately pop out of the traps, limiting the downward force that can be applied.