Use a scarf joint to connect beams together securely. A scarf joint uses a long angle that is cut into both beams. The angles match each other to provide a large glue surface. This allows the beams to be joined end-to-end in a continuous run. Scarf joints are simple, and they can be cut with a hand saw. If the beams are decorative, you can pin-nail the scarf joint and putty the holes to barely see the seam.
Things You'll Need
2 beams, 6-by-6-by-96 inches
Straightedge, 24 inches
Pin nailer, with 1 1/2 inch nails
8 hand clamps
Lay both beams on a flat surface. Measure down 8 inches from the top corner of one beam and make a pencil mark. Using a straightedge, draw a line from the opposite corner angling across to the mark.
Cut along the line with a handsaw. Cut straight down through the beam. The beam should have a sharp spear-like point on it when you are finished.
Lay the pointed beam on top the other beam. Place the hand saw along the angled edge of the top beam and begin sawing the other beam at the same angle. Saw completely through the beam.
Smear glue on both angled cuts. Flip the top beam over and bring the two matching angles together. Shoot pin nails through the narrow angled ends on both beams.
Place four hand clamps on the joint at the top. Flip over the beam and place four hand clamps in a row along the bottom of the joint. Tighten securely. Wait one hour for the glue to dry and remove the clamps.
These measurements are for examples. You can change the length of the scarf joint according to the size of your beams. You can also shoot 2-inch staples through the scarf joint if you want more holding power.
If your beam is strictly for support and there are no aesthetic concerns, you can also drill through the joint and place bolts through for extra strength.
Always wear safety glasses when working with wood.