Mail Boss 7123, Bronze In-Ground Mounting Post, 44 x 4 x 4 inches, for Use with Mailbox,Medium

This is a very heavy duty steel post designed for ground mounting in a concrete and works great with their MailBoss mailboxes. I bought the Mail Boss 7108 Security mailbox and it has all the right hardware to easily mount to this post. I replaced an old mailbox on a wood post with this steel square post. Dug out the hole about 14" deep and 14-16" wide, put down some gravel, then a layer of quikrete , then made sure the dimension to the street from the top of the post was correct, supported the post and filled in the hole with the balance of 4 50 lb bags of quikrete cement. Added water to the cement mix in the hole from the hose. The cement cures enough after 30 minutes to install the box. Let it cure overnight while being supported plumb. Very solid install, very happy with the post and the mailbox.

Ok. It’s a fairly simple steel post. What do you need to know about a post?!Several things.MailBoss claims their steel post is galvanized steel that has a powder coat. I can confirm the powder coat, but while the outside may be galvanized and then covered with the baked on powder coat, the inside of my post was raw steel.It’s going in the ground, why does that matter?!If you bought the in 43” ground post, you’re only looking at about 12”, give or take, in the ground. If you have sandy or loose soil, you’ll need to put a wooden 4x4 inside.No biggy .. just go to the big home improvement store, buy a pressure treated post and stick it inside, right?No!!!The inside of the steel post might be raw or might be galvanized. EITHER way, if you put a pressure treated 4x4 inside the steel post, bad things will happen.There’s copper in the pressure treatment used in the wooden post. When copper and zinc touch (zinc is the galvanization used to protect the steel) or to a lesser extent, when copper and steel touch, you will get galvanic corrosion which will first quickly eat away at the zinc and then eat away at the steel. Every spot where the pressure treated wood touches the metal, the metal will corrode. Eventually, it will corrode Badly!So, if you go with a non pressure treated wood, you won’t have galvanic corrosion, but the wood will rot from the moisture in the concrete.So .. what you need to do is first buy a quality pressure treated 4x4. I went to a lumber yard. It was a few dollars more, but it had a much better pressure treatment. It was a darker green color, meaning more copper protection for the wood, but that also means more copper for galvanic corrosion.Now, when builders have metal that comes in contact with pressure treated wood, they use a barrier to prevent the two from coming in direct contact and they use stainless steel fittings which greatly minimizes any potential galvanic corrosion.The metal post has a large enough inside diameter that you can buy some thick heavy duty plastic sheeting and wrap the wooden post in one to two layers of the heavy duty plastic. I purchased a roll of heavy duty 6 mil plastic which was the thickest I could buy at the local hardware store.I made sure I had full coverage of the wood going into the steel post. I wrapped the plastic about 1.5 times around the length of the post (I used packing tape to hold the plastic in place) and I left about 3 to 4 inches of extra plastic on the top end going into the steel post. That way, when the wooden post is inserted inside the steel post, even the top end of the wood can’t contact the steel. The wrapped wooden post slid into the steel post with no problem at all. On the bottom end, I ensured I had about 6” of plastic past the end of the steel post that was still covering the wood. I cut my wooden pressure treated 4x4 post long enough to be fully inserted and still have 16” sticking out the bottom of the steel post.(Note: make sure there are no metal burrs on the open end of the steel post, including the lower holes, that can cut the plastic when the post is being inserted.)(Note: MAKE SURE the bolts used to mount the mailbox on the top of the steel post are fully screwed in when you insert the wooden post. Otherwise you may have trouble getting the mailbox mounting bolts to go in after you’ve inserted the wood AND you may end up causing galvanic corrosion through the supplied galvanized steel bolts.)Once the wooden post was inside, I used 4 stainless steel lag bolts to ensure the wooden post doesn’t separate from the steel post. (Using lag bolts to connect the wood and steel posts is recommended by MailBoss, but they didn’t supply the lag bolts.)(Note: when you tighten the lag bolts, the powder coat WILL be damaged. I spayed the bolts and surrounding area with Rustoleum Enamel paint from a rattle can to ensure it won’t rust from moisture in the concrete.)Now that the post is properly prepared, NOW it’s simply a post (all be it a much heavier post) that you’re placing in the ground. Buy some bags of instant concrete, pour a few inches in the hole, insert the post, pour in the remaining concrete from the first bag, wet it, add the next bag, wet it, etc .. and in a few days, your post will be rock solid.Hope this helps you have decades of corrosion free service from your steel mailbox post.PS: The MailBoss information that comes with the post only shows a wooden post going part way up the inside of the steel post. My thought was if the wooden post is completely inserted, the steel post is now for all practical purposes, solid .. meaning your post is less likely to be dented if something accidentally hits the post.

I purchased the 7121 post to support the Mail Boss 7106 mail box. The Mail Boss 7121 in-ground steel post is 4”x4” with a hollow interior that will fit snugly over a standard 3.5”x3.5” wood post (although the wood post will need to be reasonably straight). The steel post weighs 14 pounds. It is completely open at the bottom end and has a square 4 and 3/8 inch wide steel top plate securely welded over the top end of the post. The steel walls of the post are roughly 1/16” thick and quite sturdy. There are four threaded holes in the top plate that are spaced in a square that is 3 and 11/32 inches (center-to-center) apart. The four holes extend through the top plate into the hollow interior of the post (not outside of it). The mounting plate included with the Mail Boss 7106 mail box has a total of 24 3/8” holes arranged symmetrically in it, and four of these holes line up very nicely with the four threaded holes on the top plate of the 7121 steel post. The post includes four lag bolts with which to secure the mounting plate to the steel post. Strangely, though, the heads of these four lag bolts require an 11 mm wrench – a ½ inch wrench will strip the lag bolts’ drive head. It’s very strange they would use 11 mm heads and not ½ inch. One of the four sides of the post has no holes in it, but the other three sides each have two 5/16” holes, one located 1 and 3/8 inch (to the center of the hole) from the bottom of the post and the second located 4 and 3/8 inch from the bottom of the post. These holes can be used to secure the steel post to a 3.5”x3.5” wood post with six No. 10 (or ¼ inch) by 2” lag screws or the like, which are not included and must be purchased separately. I would use nothing but a zinc-coated steel lag screw (19 cents each at any Home Depot) to avoid possible corrosion due to dissimilar metals where the screw head touches the galvanized steel post when it is placed in the ground.Both the 7121 post and the 7106 mail box were completely black. When the post is set into the ground, the mounting plate is bolted onto the top plate of the post. The heads of these bolts will be inaccessible to a thief once the mail box is placed onto the mounting plate and secured to it with the two bolts described above that are accessible only by unlocking the mail door with one of the included keys. After bolting the mounting plate to the post, one slides the mail box onto the mounting plate, and then attaches them with the two screws previously mentioned. No bolt or screw can be accessed by a thief unless they open the lockable door.U.S. mail regulations require that the mail entry slot of the mail box be located between 41 and 45 inches above the road surface. The mail entry slot on this mail box is approximately 12 inches above the top plate of the steel post when the mail box is mounted on the post using the included mounting plate. Since the post is 43” long, this means that you will only be able to sink about 10 to 14 inches of the steel post into the ground if the roadway is level with the ground onto which you will mount the mail box. If you are on a residential street with a curb and you will mount the mail box into ground that is a few inches above the street surface, you may be able to sink the steel post a few inches more. But even this is probably not deep enough to securely hold the heavy mail box, even if you concrete the post all the way up to the surface. It is highly likely that you will want to use a pressure-treated wood post inside the hollow steel post to enable you to sink the post significantly deeper – particularly if you do not use concrete. In cold climates, you probably want to be at least 3 to 4 feet deep in the ground. Note also that the front face of the mail box should be between 6 and 8 inches back from the side of the road surface (close enough for the postman to reach it comfortably but not so close that he hits the mirror of his van on it).I had a handy man install my 7121 steel post (with a longer wood post inside it). He charged $150, but I gave him a little more because it was difficult to break up and remove the concrete footing from the previous mailbox post. He used an 80 pound bag of Quikrete to install my post. Installation of the mailbox on the post once it was installed was easy and quick.

Beau fini. Un prix vraiment fantastique au moment de mon achat

Easy to install

Like how you can insert a 4 x 4 wooden post to help strengthen it