The splicing (joining) together of two beams is carried out using a joist hanger, a hammer and nails. Joist hangers are made of metal and come in various sizes to fit different widths of lumber. Holes around their sides allow for nails to be driven into the wood to firmly secure two pieces of wood together. Each hanger also helps to keep wood straight if future warping happens due to the wood not being sufficiently dried out.
Measure and cut both beams to length using a circular saw. Use medium sandpaper to remove any splinters from the cut ends. Stand both beams on their sides and position the end of beam #1 against the side of beam #2 in the place where the two beams need to be joined together.
Run a carpenter's pencil along beam #1's end (both sides) that is resting against the side of beam #2. This will create two parallel lines on the side of beam #2, marking the position where beam #1's end will attach to it.
Hammer a 16d galvanised nail at a 45-degree angle through the top of beam #2 into the end of beam #1 (this is to hold the two beams in place). Push the U-shaped joist hanger up onto beam #1 from its bottom, and slide it into position against beam #2. Check that there are no gaps between both beams and the hanger.
Knock the speed prongs on each side of the hanger into beam #2 with a hammer (this will help keep the hanger in place for nailing). Hammer joist nails through the hanger's holes into beam #2, then hammer joist nails through the hanger's holes into beam #1.
Use the correct size joist hanger for the size of beams you are attaching together, as well as the correct size joist nails for the hanger. Hammer nails into every hole in the joist hanger to make the join between the two pieces of wood as strong as possible.