I have a home gym and recently began working out with friends of very varied heights --my tallest workout buddy stands 6'5" and the shortest at 5'4". Pull ups are an important upper body exercise, so I thought it would be great to build and install a pull up station with an adjustable height bar hanging from rafters.
The goal was just to suspend two 2x4's from the rafters with multiple holes drilled to fit a 1" pipe. Initially, getting the right measurements to cut my 2x4's and drill the holes seemed like it would be a headache due to the geometry of the rafter trusses and roof. Fortunately, I realized I could reference the "bottom chord" (the dark brown horizontal span) and the two light brown 2x4s running perpindicular as referencing surfaces to simplify my measurements. Using these references, I only needed a few easy measurements and some geometry to line everything up:
I'm pleased with how well all 4 positions line up, especially given that I only used a 1-3/8" spade bit which was not very over-sized. It was fun explaining to one of the kids I had helping me that 2x4's measure 1.5" x 3.5" and a 1" pipe has a 1.32" OD.