best/safest way to hang a 2" rope on a 4"by 12"wood beam?
Hitch knots are strong and simple. If you plan on using both ends for climbing or pullups, a cow hitch will work. If you want to only use one end, and be able to easily undo the knot with the other, try a highwayman hitch. And if you don't have access over the top of the beam, you can use a thick eyebolt.