I had the head on mine move on me once while I was pocketing in some pretty tough steel. I replaced the bolts and nuts that clamp the column with grade 8 fasteners. Then a thorough coat of grease on the threads will reduce the torque required to lock the column tight. Not a single problem since. As far as locating the head after moving it, I have heard of someone using a laser pointer aimed at a far away wall with a straight vertical line drawn on it. Obviously the farther away the wall is and the more level your machine is, the better this will work. Personally, I just use a center in the chuck to locate the head to a hole of a known location while I tighten the bolts. (keeping the quill almost locked so it can't wander) This has worked for me when doing rough work (+ or - .004) and is fairly convenient because I usually need to lower the head right after all the drilling is done. If I need a closer tolerance than this, I either use an edge finder or go find some U.S. made iron! I like the ideas being put out here. Keep em' coming guys.  |