I am about to mount some steel pipe which spans from one wall of a room to the opposite wall. (Here's why: Mount Pull-up bar from wall to wall)
How do I accurately mark two points on facing parallel walls so that the points are directly opposite each other? By directly opposite, I mean that the line joining the points should be horizontal and should also be perpendicular to both walls.
Additionally, I have a hook suspended from my ceiling and it would be nice if I could accurately mark the points so that the line joining them passes directly below this hook in addition to being level and perpendicular to the walls.
Best Answer
Why not buy the pipe, and make the marks based on that. That is, have a level, hold the pipe up and level it, then mark where it touches the wall. A friend would help, so might hanging or otherwise supporting the pipe from either above or below as you do this.