Magnetic Dice Vault

Become the envy of game night with this eye catching magnetic dice vault. The vault doubles as a display allowing you to gaze upon your tools of trade while doing battle with your foe of choice. Made from solid walnut and maple wood this vault not only looks good, but can also take a beating (probably). It features cut outs for a set of seven die (D20, D12, 2x D10, D8, D6, D4), but could easily be adapted to meet your specific needs. The walnut end caps are held in place with strong neodymium magnets that secure the vault close for storage and keep the two halves aligned when in use. It also bears a strong resemble to a scroll when held in the middle (that's got to count for something, right?).

I developed this dice vault to help keep my dice organized during DND campaigns. As a new player, I find myself digging through my dice pile in search of the correct value. This often entails me turning each die over to all sides in order to determine it's max value. I wanted to create a solution that would allow me to keep my dice in order and also function as a case when not in use. I opted to customize my vault with a character name with plans to add more ornate decorations in the future.

Supplies

Supplies

• 4x round neodymium magnets
• Cyanoacrylate (super) glue
• 1x Walnut board (end caps) - Approx. 4 x 2 x 1 inch
• 1x Maple board (top) - Approx. 9 x 1.5 x 0.75 inch
• 1x Maple board (bottom) - Approx. 9 x 1.5 x 0.5 inch
• 1x Set of dice
• Sandpaper
• Block plane or Router w/ chamfer bit
• Danish Oil

Software

• Fusion 360
• InkScape
• Carbide Create

Equipment

• CNC Router
• 1/4" End Mill (Carbide #201)
• 60 degree V-bit (Carbide 3D #302) // optional
• 3D Printer // optional
• Cordless Drill & Bit
• Random Orbit Sander

Step 1: Capture Dice Outline

The process beings by arranging the dice on table top and capturing an overhead image. Perfect alignment and orientation is not required.

Next, import your image into Inkscape.

Trace the outline of each die using the polygon tool with the appropriate number of sides (D20, D10, D8 = 6 point polygon, D6 = 4, D4 = 3, D12 = 15). It's helpful to create a new layer for these outlines to keep organized.

Using the align / distribute tools arrange the die outlines in your desired orientation. I opted for even spacing between die, with middles aligned. Once you're happy with the arrangement, create a group.

Draw a rectangular bounding box around the dice group, then use the alignment tools to center and distribute as desired.

Export the file as a SVG making sure to either remove or disable the imported image (we only want the outlines and the bounding box).

Step 2: Import SVG

Create a new project in Fusion 360, then import the SVG from the previous step (Insert -> Insert SVG).

The SVG most likely will not be scaled properly when imported, however we can apply a scale factor to correct this. I used the "inspect" tool to measure the size of the imported D6 and compared against the actual object. Calculate the scaling factor and apply an appropriate tolerance (I added ~10% to allow for different dice and manufacturing artifacts).

The result of importing the SVG is a sketch which can be used to build the 3D model.

Before we begin modelling, we will create some key parameters such as the desired length, width, height and material thickness. When building the model these parameters will be used as variables, allowing us to quickly update a model without the need to redo a bunch of work. For example, if we find that the wall thickness is too thin for customization with a V-bit (as me how I know), a properly built model can be quickly updated by simply changing a single variable. This method of "parametric modeling" is a powerful feature of Fusion 360 and is absolutely worth learning (see https://www.autodesk.com/products/fusion-360/blog/parametric-modeling-in-fusion-360-tutorial/).

Step 3: Build 3D Model

Once we've imported our SVG and defined our key parameters, we can begin constructing a 3D body from our sketch. The screenshots above capture the process as described below.

I began by extruding the entire sketch by my target wall thickness (as defined in the parameters), then repeating with just the outline (dice cutout excluded) by 1/3 the thickness of my largest die (again another parameter). This forms the bottom portion of the vault.

The process of creating the top of the vault is essentially the same, but in reverse. First extrude the outline without the dice cutouts a distance of 2/3 the thickness of the largest die, then extrude the entire sketch the desired wall thickness. During this operation, make sure a "new body" is formed so as to be distinct from the bottom.

The end caps are formed by first extruding the side profile of the assembly "outward" by the material thickness, then extruding an offset version of the profile "inward" by a desired depth. A hole for the magnet is added inside the end caps, the depth and radius of which are specified as parameters.

Apply a slight chamfer to the long edges of the top, bottom and end caps.

Step 4: 3D Print & Check Fit (Optional)

It took me a few iterations to reach the final version of the dice vault, however I'm including this step to show the prototypes I went through to help convey how the model evolved. Feel free to jump forward and benefit from my mistakes.

I used a 3D printer to first check and validate the dice would fit in the model and that my tolerances were appropriate. I ultimately ended up scaling the dice slots up about 10% to allow for variations in dice sizes, as well as to allow some slop in the manufacturing process. My first prototype was a single piece print and was effectively an extrusion of the dice outline captured from Inkscape. In this prototype, I determined that a rotated version of the D4 outline was more visually appealing.

The second prototype was a two piece model and that included magnets to lock the two sides together. The "top" portion was about twice as deep as the bottom so that the bottom could be used to display the dice and allow the dice to be picked up more easily. I found two flaws in this configuration, first it was difficult to open the box and second when the two pieces were stacked to display the dice, the magnets opposed each other which caused the top to slide around.

Through these iterations I came up with the idea to use end caps to lock the two halves together, which solved both the issues I had experienced. It also gave me the opportunity to add a contrasting wood and add an interesting profile to the assembly that was different than others that I have seen online.

Step 5: Generate CAM Files

Similar to how a slicer works for 3D printing, Gcode is generated for the CNC from the 3D model through Computer Aided Manufacturing (CAM). Fusion 360 includes CAM support in the "Manufacturing" tab.

If the stock thickness were different than the model thickness a "facing" operation could be used to mill the stock to the appropriate size. I opted to plane & sand the stack to the target thickness to save time (and bit changes).

The top and bottom portions of the models each have two operations, a 2D "pocket" and a 2D "contour". The pocket cut is responsible for clearing out the portions of the model where the dice sit. The contour operation cuts the outside shape of the model from the stock.

The end caps have three operations, a "pocket" and "contour" similar to the top/bottom as well as a "bore" operation to clear a spot for the magnet to sit.

I used a 1/4" end mill (Carbide 3D #201) for all operations. For the outside contour operations the bit selection has virtually no variation from the 3D model. For the pocket operations, the diameter of the bit results in round interior corners (this will occur with any round bit, however smaller diameters will results in a product closer to the 3D model). These rounded interior corners on the end caps would prevent a square top/bottom from mating properly. This issue is addressed (later) by applying a chamfer on the long edges of the top/bottom allowing the end caps to slide on/off without modification.

Step 6: Mill Stock

It is unlikely that wood will be available in the exact dimensions required for this (or any project). For those with access to a woodshop, cutting stock to the appropriate size(s) generally involves a variety of tools such as a miter saw, jointer, planer and table saw. Milling materials is out of the scope of this project, but rest assured there are lots of good resources available describing this process (for example, https://youtu.be/cMA_aG48OM0).

If you can't get the material to the exact thickness through planning or sanding, you can also go back to the CAM step in Fusion 360 and add a "facing" operation which will remove the excess thickness from your stock until it reaches the top of your 3D model.

Step 7: Attach Stock to CNC Table

I attached my stock to the CNC table using painters tape and CA glue, (see https://youtu.be/K8i8qEnHA58). I could have used tabs to keep the piece from launching across the room, but as with most things, there are many solutions to the problem. I find when the raw stock is close to the final part dimensions, sometimes there isn't enough room to add clamps and double sided tape works just fine.

Step 8: CNC Components

Export the Gcode from Fusion 360 ("post process") and and mill the top, bottom and end caps. As previously mentioned I used a 1/4" end mill for all the operations to eliminate the need for bit changes.

I use the Carbide Motion software to send Gcode to my Shapeoko 3, this software will vary between machines.

I like to "cut air" first to verify the Gcode behaves as I am expecting. This entails zeroing the CNC off the stock and slightly elevated on the Z axis, such that when the program runs the bit doesn't make contact with the stock or the spoil board.

<Pardon the "re-enactment" images above, I was so excited how the parts turned out I forgot to take actual photos>

Step 9: Customize (optional)

I used a 60 degree V bit (Carbide 3D #302) to engrave the top lid of my dice vault with name of my DND character ("The Duke"). It was at this point I discovered that the1/8" wall thickness slightly too shallow and the deepest part of the engraving are visible from the opposite side. Fortunately, because "wall thickness" was a parameter in Fusion 360, updating the model to use a slightly thicker wall (3/16 - 1/4") is a breeze.

I used Carbide Create the generate the Gcode for the engraving, however there are many other ways to generate it as well. More elaborate engravings are also possible with V-carving, alternatively the top (bottom and sides for that matter) could be laser engraved to suit your needs.

I actually engraved the top after I applied the chamfers (see below), but recommend doing the engraving first as it is easier to zero the bit with a square edge.

Step 10: Embed Magnets in Wood

The end caps have a shallow recess to embed magnets, I used super glue to adhere the magnets in place, paying careful attention to the polarity. To make the end caps swappable, I made sure the magnets in the both left and right end cap were oriented the same.

The hole for the magnet on the top piece was not drilled on the CNC, rather I milled an extra end cap with the magnet hole going all the way through the body. In this manner, I was able to use this extra end cap as a jig to when drilling the hole in the top with my cordless drill. The actual size of the drill bit will depend on the dimensions of the magnet you select.

Once the hole is drilled in the top, I super glued the magnets in place, again paying attention to the polarity of the end caps so the magnets attract instead of repel each other.

Step 11: Route Chamfer, Sand and Finish

A chamfer is added to the long edges of the top/bottom to both add visual interest and to allow the end caps to slide on/off without modification. This operation can either be performed "manually" with a block plane and sander or utilizing a router with a chamfer bit. I found a 45 degree router bit worked pretty well, followed up with some light sanding with a random orbit sander.

Test the fit of the end caps on the top/bottom assembly. If the fit is too tight you can sand the top/bottom down until the fit is dialed in. Make small adjustments to avoid a loose fit.

A few coats of Danish Oil (or really whatever you choose) will really make the wood grain pop and help protect the wood from your grubby little fingers. Lightly sand the pieces with 220 grit sandpaper between coats, 2 or 3 layers should be sufficient.

Step 12: Dominate

With you finished dice vault in hand, go forth with confidence that your precious dice are safe in their new home. When you're ready to play, admire your dice on display and never search for that stray D8 again. Feel free to argue with your friends or DM that your shiny new dice vault is worth at least +1 to charisma and advantage on influence rolls.