Hello all. I am new to CNC and bought a Robocutters 8 x 4 machine about a year ago that I am only just getting round to building. I have been hearing stories on the openbuilds forum that it may have rigidity issues. My version uses doubled up 2080 profile on the x and y axes. the latest model uses H rail instead. My questions are: Is it simply the case that a 3.0m long Y axis is too long for the v slot profile system or, would upgrading to H rail do the job, or is there another solution. Glad to have discovered OpenBuilds anyway, hope someone can help.