I need to convert a regular MEDIUM size STEEL mailbox with only one streetside entry door to place mail in & to take mail out. I'm trying to figure out how to remove the backside of the mailbox so I can add a rear door facing the sidewalk. So far I've had no luck finding a MEDIUM size steel mailbox that has both front & rear door entries.

How would I remove the backside of a STEEL mailbox so I can add a rear door?

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  • 2
    the big question is "why bother?"
    – jsotola
    Jul 4, 2019 at 0:37
  • Hello, and welcome to Home Improvement. Unfortunately, "arts and crafts" questions are off-topic here. Jul 4, 2019 at 0:54
  • 1
    Where in the world are you ? Some countries have restrictions about mailboxes, and in other countries anything goes.
    – Criggie
    Jul 4, 2019 at 7:00
  • 1
    What is medium size to you ? postalpromailboxes.com/product/the-carlton-two-door
    – Alaska Man
    Mar 9, 2020 at 20:34

3 Answers 3


What you're going to want to do is this:

Double ended car

That back of the mail box is going to be crimped on in such a way that it can't be removed without cutting the back of the mailbox off. This would leave sharp edges, so you could round those off and then attempt to re-use the back as a makeshift door, or you could just get another mailbox and use the door from it.

There's several ways you can use the two mailboxes to make one double-ender, so that bit of creativity is up to you. I'd probably cut the back 40% off of each one and join the fronts to end up with a slightly longer "limo" mailbox.

I see what you mean about finding a "medium" double door box. They also have replacement doors that are made for bricked in mailboxes that might work for this, but they seem very expensive for what they are.

Maibox door

  • If the "medium" size of the single-door mailbox is the OP's preference then surely a 50/50 cut is preferable; converting to "limo-size" defeats part of the project's motivation.
    – Will
    Jul 4, 2019 at 8:16

You probably can't.

Mailboxes must be approved by the US Postal Service. That would seem to prohibit alterations in the box proper. Shrouding it is ok, of course.


I just made this exact retrofit and the results were excellent. First I removed the back panel which left the flange of the main portion of the box. Then I flattened the flange of the main portion of the box with a brass hammer (supporting the inside of the box with a few lengths of 2x4's. I did not think it flattened as much as I wanted it to be so then I used my Vice Grips to flatten/crimp it further. I had another mailbox of the same size so I had a donor for the new door. I drilled out the rivets which held the door to the main portion of the donor mailbox. Then I placed the donor door on the back of my new mailbox and drilled the holes in the bottom edge of the main portion of the box. I needed to hold the two layers of metal together with Vice grips when drilling the holes. Finally I used 1/4" hardware to attach the new door to the back of the mailbox. I used a screw with a wide head and a nylon lock nut. The door was initially difficult to close and open so I just needed to make a few adjustments to the shape of the flattened/crimped opening. The cost of this retrofit was much lower than the alternatives. Option 1 is QTY 2 of the MEDIUM size mailboxes which are around $20 each at The Home Depot. Option 2 is to purchase a mailbox which is specifically designed with a double door, but the only available size is a LARGE and that is around $50 on amazon.com. Option 3 is the replacement door in the image posted above, but the cost of that replacement door is around $35 on amazon.com. My retrofit was definitely the best option and it looks great

  • Welcome to Home Improvement! Thank you for your answer.
    – IronEagle
    Mar 10, 2020 at 4:09

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