Things You'll Need
Instructions
Set your tri square across the width of the board, about an inch from one end, and, with your pencil, make a straight line across the broad. Cut at the line with your circular saw to get a straight right-angle edge.
With your tape measure and pencil, make a mark exactly 2 feet from the newly cut edge of your board. With your tri square, extend the mark across the width of the board. Cut at the line with your circular saw.
Hold your tape measure along the width of the board, about 2 inches from either end, and mark it at 4 3/4 inches. This should be the exact middle of the width, since modern 2 by 10 boards are actually 9 1/2 inches wide. Measure to get exactly 2 inches from the end of the board, and intersect it with your first line, so you are left with a mark 2 inches in from the end at the middle of the width. Repeat on the other end.
With your drill and 1-inch boring bit, drill a hole at the two marks you've made, 2 inches in from each end at the middle of the width.
Sand all surfaces of the wood smooth, rounding off all the corners and smoothing out any splinters.
Thread the two lengths of rope through the two holes from the side you want to make the top surface of the swing. Tie a sturdy knot in the end of the rope that comes out the bottom. Hang the swing from a tree branch or swing set. When tying the top ends of the rope around the branch or swing set bar, set the level on the swing and adjust the rope lengths accordingly.