Guide Rail Failure on Longmill MK1 CNC

This is the adventure I went on to figure out why my Longmill CNC was drilling too deep on my project and moving the wood base around. I heard grinding when that gantry moved and that combined with the problems it was having cutting at the correct Z depth should have clued me in that the problem was with the bearing guides.
I am thoroughly enjoying my Longmill CNC and I'm grateful I figured out what was wrong and could easily fix it.

[@nevercine]

Good learnings!