Mailmaster mailboxes are mounted by securing them to a wooden post. The post is buried in the ground to secure it, and the mailbox slides over the top. Two wood screws anchor the mailbox to the post.
United States Postal Service (USPS) regulations require rural mailboxes to be mounted with the bottom of the mailbox 42 inches from the ground and on the right side of the road as traveled by the mail carrier.
Install Mounting Post
Choose a location for mounting the mailbox. Dig a hole six inches around with a post-hole digger or small shovel.
The hole should be as deep as the frost line in your area, but at least two feet deep. Line the bottom of the hole with gravel or small rocks to promote drainage.
Consult the mailbox installation instructions and determine the length of post which must be exposed above ground. Add this to the depth of the hole. This will be the length of the post needed.
Cut a piece of 4-by-4-inch pressure-treated wood to the length required. Place this post in the hole and fill with dirt. Use a level to assure that the post is plumb in both directions.
You may wish to tilt the post slightly out of plumb so that the front of the mailbox tilts slightly toward the ground. This will reduce the amount of rainwater that seeps into the mailbox.
For added stability, the hole can be filled in with concrete rather than dirt. Simply fill the hole with the contents of a bag of premixed cement and allow natural groundwater to harden the concrete over time.
Mounting a mailbox in concrete has one disadvantage. If your mailbox is hit by a vehicle, the 4 by 4 post will break at ground level. But you will not be able to replace it in the same spot because of the concrete.
Mount the Mailbox
After the post has been installed in the ground, secure the mailbox to the post. Slip the column of the mailbox over the post, then secure it with two wood screws.
Predrill the post for the screws with a bit slightly smaller than the supplied bolts to reduce the chance of the post cracking. Install the screws and tighten securely.
USPS regulations require the mailbox to be clearly marked with your house number.