So the half-lap joinery is cut. Now it's time to put these two parts together using a weather proof glue and three inch decking screws.
When I cut the joint I made certain to stay just slightly inside the layout lines so the fit would be too tight. Then I nibbled away a tiny amount of material using my crosscut sled at the table saw until the fit was perfect.
I applied a waterproof glue to all the mating surfaces, put the two pieces together, predrilled and countersunk the holes for screws, and sunk two three inch coated deck screws into each side of the joint, for a total of four screws.
Here is the blank I glued up to form the base to secure the mailbox to the post. It's made from some reclaimed pressure treated 2 x 6 material, edge glued with the same waterproof glue I used on the joint for the crosspiece.
After clamping it in place on my assembly table, I drove three screws through the narrow piece into the wide piece. After that the clamps weren't needed and I could continue without waiting for the glue to dry.
I then cut the blank to length (staying well away from the screws), and cut it to width to fit inside the bottom of the mailbox my neighbor purchased for this project.
And here's the angled brace I used for this mailbox post. When I built my own mailbox post I used a pair of pressure treated 2 x 4 braces, one on each side of the post, and I used templates to rout my street number into each of them. My neighbor, however, wants to put some brass numbers she purchased on her mailbox post. These numbers are 3.5 inches tall, so 2 x 4 material would be too narrow. In order to leave room for these brass numbers I chose to use one piece of 2 x 6 material, mitered on each end and screwed into place, centered on the post. This leaves plenty of room for the numbers and gives the whole unit a different look than mine has. And since these two posts will be across the street from each other for several years, it seems like a good idea to have a slightly different style for each.
Next time, I'll finish this project and install it in my neighbor's front yard.