I have a Grizzly 1006, which is one of the much maligned round column mill/drills that are sold under various brands. Yes, I want a knee mill, but for right now, this will have to do. Much of the whining about the round column is having to try to return to the head to center after raising or lowering it. I rarely have to move the head, but if I do, I have found a very simple way to check it. I set a dial indicator on the vise and rest the pointer on the round spindle end. I move the head side to side until I find the highest point. The head should now be exactly perpendicular to the bed. This only takes about 2-3 minutes to accomplish and seems to work well. At least it works for me.