Building The Vault Style Piggy Bank

You can download a set of plans here and build your own piggy bank
I have seen a lot of piggy banks made using these mailbox doors, but all of them either lack style, or are mass-produced in a way that they are cheaply made and lack style. I decided I wanted to make mine with a little style and a better quality.

When I see these PO Box/mailbox doors I am always reminded of the old movies showing the star about to be robbed when he goes to gets his mail or the door is rigged with a bomb.  Therefore, I decided to take inspiration from an old post office building made of brick.

Many old brick buildings have an architectural style where the bricks on the corner of the building weave together or stick out a little further than others to create a decorative effect.  To simulate this effect I decided to join the corners of the wood together using mitered keys in a contrasting wood.  I used walnut for the mitered keys and top, and I used maple for the main body of the bank.

I took care when cutting out the maple for the main body to keep the boards in order so when I assembled the box the grain would wrap around the corner, giving it the effect, that the board is folded into a box shape.

Since it is hard to cut miters accurately with an accurate length from one large piece of wood, I cut the board into four pieces.  I then set up a stop using my Incra so I could cut all the pieces the same length, with accurate miters.  Yes, the extra cut removes more material from the board causing the grain not to follow as perfectly as it could around the box, but having a perfect miter is a good trade off.

I then set up a 1/4″ dado blade to cut the groves for the bottom, and top to rest in.  With the same setup, I cut the grove in the top as well.  This took a few test cuts to be sure the top and sides joined together without having to jam them together.

I used a 1/4” drill bit to cut the hole in the top for the coin slot. Yes, I realize that this looks crazy in the video as I force the drill bit sideways to smooth out the space between the drill holes. However, I think it is safer than trying to hold on to such a small piece of wood and rout a through hole and slot in it. It is also much faster to chuck up a drill bit in the drill press over chucking up a router bit in the router table along with stops marks/blocks to prevent from over routing. Besides drill bits are cheap compared to my time.

I used a shop made jig to cut the slots for the miter keys, taking care to space them evenly down the sides, and I used my planer to thickness down the walnut to the same width as the saw blade kerf. I glued them in, sawed them off, and sanded them smooth.

Installing the mailbox door was pretty straightforward. The directions for how big to cut the opening can be found on Rockler’s website, which is where I got the doors. Since I was building three of them for a customer, I cut a block of wood the size of the door opening, and used that as a template to trace out where to cut. All I had to do was center the block on the box and trace around it, drill a few starter holes, and cut it out with my jigsaw.

To finish it all up, I sprayed on a few coats of a gloss lacquer, added the brass coin slot, packaged them up, and shipped them to their new home.

These are available to purchase on my custom furniture website