Hi All, I'm working on designing the second version of a CNC machine I built over the summer. The one I made was very sloppy in how it moved. I attribute this to the belt and pinion approach I used. I just can't help but feel like the belt stretches. That stretching must cause inaccurate movement, especially as it must stretch and contract while the machine runs. Because of this, I'm thinking about switching to either a lead screw mechanism or a rack and pinion mechanism, at least for the horizontal axes. I really want to find some long lead screws. At a minimum I'm looking for 1300 mm length (ideally something more like 1800 mm). I probably want larger diameter than the 8mm one OpenBuilds offers. I've google the bejesus out of this and there are lots of manufactures, but I'm having a very hard time finding a clear combination of the following: 1) Metric 2) >= 1600 mm 3) Simple off the shelf mounting hardware. IE: The equivalent of the acme nut block and the threaded rod plates offered by OpenBuilds. Any suggestions on where to look / who to talk to? Thinking about the rack and pinion, I still need to research what sort of specifications would work best for the project at hand. Anyone known anything in this area? How would you solve the linear motion on a large CNC machine? Thanks for the feedback, everyone!