[m1911bldr]

I've read a lot of the threads about building routers and have seen some questions and suggestions about how to get the table/frame flat so the rails/guides are parallel and true to each other. When I built my machine, this was one of my most basic concerns, since the first set of rails (X axis in my case) determine the trueness and "twist" of the entire machine. I used plumb bobs, 2 lb monofilamnet fishing line (sewing thread proved to be too fuzzy) and a micrometer to measure the plane-trueness/twist of the frame. With the frame standing on end, I hung the plumb bobs off the top two corners and VERY CAREFULLY measured the gap between the line and the bottom two corners. Even after "jigging' the frame to weld it, it was twisted .033. I mixed up a 50/50 mix of JB Weld and Brownell's Atomized Steel and made mount pads for the rail supports. The X rails are well within .001 of each other in twist, now, over a 44" distance.