"US Mail" mailbox door

Our mailbox door rusted off, and we needed to either fix the door, replace the door, or replace the mailbox. I opted for replacing the door, by designing my own door to be 3d printed.

This is the result.  This is a parametric design I made in OpenSCAD, so is easily adaptable to many different mailbox door shapes (at least the ones that feature an arched design).

I have also included the .stl render that I ultimately used for the current version of the door I have on my mailbox now. You likely will want to download and use OpenSCAD to customize the design for your specific mailbox. OpenSCAD is available for Windows, macOS, and Linux. It's not hard to use, especially if you're just tweaking the parameters in the customize panel that I have made.

My first try was using the living hinge version, printed out of PLA. Printing out of PLA was a mistake (I had not printed out of other materials at the time yet). The living hinge had some issues out in the sun, and eventually after months, into summer with 95°F days, it warped pretty badly. I changed the type of hinge and did a few other small tweaks, and the result is the STL included.

It includes two different hinge styles you can use - a living hinge (where the plastic bends at a thin point in the door, which will potentially fail eventually due to fatigue), or a piano hinge.

For the living hinge, I used the “BOSL2” OpenSCAD library from GitHub. I have included a zipped copy of this, expand in the same directory that Clone or download the library from github, and put it in a subdirectory called “BOSL2” adjacent to the .scad file. BOSL2 is licensed under the terms of the BSD 2-clause license.

For the piano hinge, I used Code and Make's hinge design, licensed under the MIT license. I have included a copy of the .scad with this design. I did not do so with BOSL2, because the library is so large.

The knob is from Make_A_Shape, here on Printables, licensed CC-BY-NC.

This design assumes you have a magnet that holds the door to your mailbox closed. To accomodate this, there is a slot within the middle of the design that you can insert a metal slug into that serves as the ferrous piece that will keep the door closed. By default it is the size of the innermost circle of metal punched out from an electrical junction box (I had these handy lying around, and they weren't useful for anything else). You can adjust the SCAD model so the hole is sized for whatever round piece of ferrous metal you may have lying around. A washer works well as well. 

This metal slug will be printed ontop of, so make sure that it is nice and clean, without body oils on it. I actually applied a bit of 3d printing glue to it to make it even easier to print ontop of. Prior trials had some failures (globby bits of plastic around the slug because it didn't adhere properly) - so do be sure that it is clean/without oils. It's not super important for it to print that first layer ontop of it perfectly, as it will have quite a few layers above it to smooth out, but big blobs will extend up to the top surface as layers try to print ontop of the blobs.

Note, when slicing, go into the “Preview” tab of Prusaslicer/Bambu Studio/OrcaSlicer slide the layer down to the bottom layers, where you see the hole for the slug to fit into. navigate to the first layer that covers that hole. Right click the layer slider, and choose “Add Pause” (It will be layer 10 if you use 0.2mm layers). This will insert some G-Code that tells the printer to pause just before it starts printing that layer. When printing, once the printer pauses, insert your metal slug.

This just uses the knob, unchanged, within my design. The rest of the design is unique/separate from the knob.