I just completed some upgrades on my kickstarter Robo 3D. I installed the couplers, brackets and switches today replace the original single Z axis. I replaced the J-head with an E3D V6 and dual parts fans. I also uploaded the newer R1 firmware so I could use auto leveling. I started Matter Control and used it to raise the Z axis which made a grinding noise while moving either up or down. The X and Y axis sounded fine. It'll be a couple days until I can work on it again but I did find one possible lead. I found a video online of someone who's Robo made a similar noise after upgrading to 8mm threaded rods. The poster commented that he fixed it by adjusting the trim pot to give the stepper motors a little more power. This seems plausible as the kickstarter x carriage rides on a pair of 'regular' sized nuts but I'm now using larger threaded couplers with brackets and microswitches attached, which must be increasing the drag on the threaded rods. Thoughts?