Hello everyone, First off, I apologize as I'm sure some of these questions have been asked before, but I'm not having much luck finding the specific answers I seek when searching. So I figured I'd post here and see if anyone had some feedback for me. To describe my goal, I'm currently in the research stage of planning to build my own diy cnc mill. My eventual plan is to have it with swapable heads so that I can use the same machine for routing, 3d printing, pen drawing, and possibly some vinyl / other cutting (not sure on the last yet but it's the least important to me). I'm looking to have my initial build have a printable area of at least 18" x 18" x ?? (haven't decided on a desired height yet, I'd say at least 8" though). So in doing research I came accross this website and it seems to have a lot of the parts that I'd like to make my build easier. The linear rails available and v wheels being a big part of the movement system I would like. However I have a question regarding the OpenRail. I really don't understand the point to using it in conjunction with a V Rail? All the video demonstrations of it show it being used like that, but it looks to me like you could simply slap that OpenRail on a piece of wood and have a working linear rail system for pretty cheap... I don't think I really plan to use wood for my linear rail I'm just illustrating how I don't see the need for both systems. Seems to me you can get by perfectly fine with either only a V Rail and solid V Wheels, or an OpenRail and Delrin V Wheels. Another question is concerning threaded rod vs timing belts. Specifically the Pros / Cons of each. One thing I read about timing belts is they are more prone to slippage with heavy loads. I do want my cnc to be able to mill aluminum so not sure if that might be an issue? However another thing I read said threaded rod was more prone to backlash and binding, which would be catastrophic as well. One appealing thing I like about using belts for movement is the easy of homing, I can simply switch off power to the steppers and move everything back into the zero position. I wouldn't be able to do that with threaded rods, would have to use the steppers to move it back. My final question for now (there will be plenty more later if communication is good on here I'm sure), in some videos I see a hose attached near the tip of the router. Some of them look like shop vac hoses, but others look like they are blowing air out (presumably to keep the work surface clear). Is one method substantially better than the other for this? Thanks for any answers!